WO2012153625A1

WO2012153625A1 - Coated film

Info

Publication number: WO2012153625A1
Application number: PCT/JP2012/060872
Authority: WO
Inventors: 川崎泰史; 藤田真人
Original assignee: 三菱樹脂株式会社
Priority date: 2011-05-07
Filing date: 2012-04-23
Publication date: 2012-11-15
Also published as: JP5355620B2; JP2012232534A

Abstract

Provided is a coated film that is suitable for use in situations when it is necessary for a hardcoat layer or the like to have good visibility and adhesion properties, and to be capable of absorbing ultraviolet rays, e.g. in various types of optical films such as the members of a liquid crystal display. Specifically provided is a coated film having a coating layer as the outermost layer on at least one surface of a polyester film, wherein at least one layer of the polyester film includes an ultraviolet ray absorber, and the coating layer is formed from a coating solution including a metal oxide and at least two crosslinking agents, and has an absolute reflectance with a minimum value in the wavelength range of 400-800 nm, said minimum value being an absolute reflectance of at least 4.0%.

Description

Coating film

The present invention relates to a coated film, for example, a coated film that needs to reduce interference unevenness due to reflection of external light, such as a liquid crystal display, a plasma display panel, and organic electroluminescence.

In recent years, polyester films are frequently used for various optical films, and are used for applications such as touch panels, antireflection films, prism sheets, light diffusion sheets, and electromagnetic wave shielding films, which are members of liquid crystals and plasma displays. The base film used for these members is required to have excellent transparency and visibility.

These films are often hard-coated to improve performance such as curling prevention, scratching prevention, and surface hardness. Moreover, as a base material, the polyester film excellent in transparency and mechanical characteristics is generally used. In order to improve the adhesion between the polyester film and the hard coat layer, an easily adhesive coating layer is generally provided as an intermediate layer. For this reason, interference unevenness occurs unless the refractive index of the three layers of the polyester film, the easily adhesive coating layer, and the hard coat layer is taken into consideration.

If a film with uneven interference is used for a display such as a touch panel, it becomes poorly visible and difficult to use. Therefore, it is required to take measures against interference unevenness. In general, the refractive index of the coating layer for reducing interference unevenness is considered to be around the geometric mean of the refractive index of the polyester film of the substrate and the refractive index of the hard coat layer, and is adjusted to the refractive index around this. Ideally. Since the refractive index of the polyester film is high, it is generally necessary to design the coating layer with a high refractive index.

An example of improving interference unevenness by increasing the refractive index of the coating layer is, for example, a method of combining a metal chelate compound having a high refractive index and a resin in the coating layer (Patent Document 1). In this case, the stability of the coating solution may not be sufficient depending on the combination due to the instability of the metal chelate in the aqueous solution, which may lead to an increase in the liquid exchange work when producing for a long time. . Moreover, the high refractive index material used normally is inferior to adhesiveness with surface functional layers, such as a hard-coat layer. Therefore, a coating layer that can effectively improve adhesion even when combined with a high refractive index material is required.

In recent years, various optical films are also used in applications such as e-books, car navigation systems, and game machines that are used outdoors. Particularly in the case of outdoor use, the amount of ultraviolet rays increases, so there is a concern about deterioration of members such as liquid crystal. Therefore, a function for protecting various members from ultraviolet rays is required.

JP 2005-97571 A

The present invention has been made in view of the above circumstances, and the problem to be solved is that interference unevenness due to reflection of external light is reduced, the adhesiveness with various surface functional layers such as a hard coat is excellent, and ultraviolet rays are absorbed. It is in providing the coating film which can be performed.

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

That is, the gist of the present invention is a coating film having a coating layer on at least one outermost layer of the polyester film, wherein at least one layer of the polyester film contains an ultraviolet absorber, and the coating layer is a metal oxide. Product (A), and two or more kinds of crosslinking agents (B) each selected from the group of oxazoline compounds, epoxy compounds, melamine compounds, isocyanate compounds, carbodiimide compounds, metal chelate compounds, and silane coupling compounds A coating film characterized in that it is formed from a coating solution and has one minimum value in the wavelength range of 400 to 800 nm, and the absolute reflectance at the minimum value is 4.0% or more. Exist.

According to the coated film of the present invention, when various surface functional layers such as a hard coat are laminated, interference unevenness due to reflection of external light is small, adhesion with various surface functional layers is excellent, and ultraviolet rays can be absorbed. Can be provided, and its industrial value is high.

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

The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyester includes polyethylene terephthalate and the like. On the other hand, examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (for example, p-oxybenzoic acid). One or two or more types can be mentioned, and examples of the glycol component include one or more types such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol and the like.

The polymerization catalyst for polyester is not particularly limited, and conventionally known compounds can be used. Examples thereof include antimony compounds, titanium compounds, germanium compounds, manganese compounds, aluminum compounds, magnesium compounds, calcium compounds and the like.

In the polyester film of the present invention, it is necessary to contain an ultraviolet absorber in order to improve the weather resistance of the film and prevent deterioration of the liquid crystal of the liquid crystal display. The ultraviolet absorber is not particularly limited as long as it is a compound that absorbs ultraviolet rays and can withstand the heat applied in the production process of the polyester film.

As the ultraviolet absorber, there are an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable from the viewpoint of transparency. Although it does not specifically limit as an organic type ultraviolet absorber, For example, a cyclic imino ester type, a benzotriazole type, a benzophenone type etc. are mentioned. From the viewpoint of durability, a cyclic imino ester type and a benzotriazole type are more preferable. It is also possible to use two or more ultraviolet absorbers in combination.

The cyclic imino ester-based ultraviolet absorber is not limited to the following, and examples thereof include 2-methyl-3,1-benzoxazin-4-one and 2-butyl-3,1-benzoxazine-4. -One, 2-phenyl-3,1-benzoxazin-4-one, 2- (1- or 2-naphthyl) -3,1-benzoxazin-4-one, 2- (4-biphenyl) -3, 1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, 2-p-benzoyl Phenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one 2-cyclohexyl-3,1-benzoxazin-4-one, 2-p- (or m-) phthalimidophenyl-3,1-benzoxazin-4-one, N-phenyl-4- (3,1-benzo Oxazin-4-one-2-yl) phthalimide, N-benzoyl-4- (3,1-benzoxazin-4-one-2-yl) aniline, N-benzoyl-N-methyl-4- (3,1 -Benzoxazin-4-one-2-yl) aniline, 2- (p- (N-methylcarbonyl) phenyl) -3,1-benzoxazin-4-one, 2,2'-bis (3,1- Benzoxazin-4-one), 2,2′-ethylenebis (3,1-benzoxazin-4-one), 2,2′-tetramethylenebis (3,1-benzoxazin-4-one), 2 , 2'-Deca Tylene bis (3,1-benzoxazin-4-one, 2,2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2'-m-phenylenebis (3,1-benzo Oxazin-4-one), 2,2 '-(4,4'-diphenylene) bis (3,1-benzoxazin-4-one), 2,2'-(2,6- or 1,5-naphthylene ) Bis (3,1-benzoxazin-4-one), 2,2 ′-(2-methyl-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2 -Nitro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 '-(2-chloro-p-phenylene) bis (3,1-benzoxazin-4-one), 2 , 2 '-(1,4-cyclohexylene) bis (3,1-benzoo Xazin-4-one), 1,3,5-tri (3,1-benzoxazin-4-one-2-yl) benzene, 1,3,5-tri (3,1-benzoxazin-4-one) -2-yl) naphthalene, 2,4,6-tri (3,1-benzoxazin-4-one-2-yl) naphthalene, 2,8-dimethyl-4H, 6H-benzo (1,2-d; 5,4-d ′) bis (1,3) -oxazine-4,6-dione, 2,7-dimethyl-4H, 9H-benzo (1,2-d; 4,5-d ′) bis (1 , 3) -Oxazine-4,9-dione, 2,8-diphenyl-4H, 8H-benzo (1,2-d; 5,4-d ′) bis (1,3) -oxazine-4,6- Dione, 2,7-diphenyl-4H, 9H-benzo (1,2-d; 4,5-d ′) bis (1,3) -oxazine 4,6-dione, 6,6'-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6'-bis (2-ethyl-4H, 3,1-benzoxazine -4-one), 6,6'-bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6'-methylenebis (2-methyl-4H, 3,1-benzoxazine) -4-one), 6,6′-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-ethylenebis (2-methyl-4H, 3,1-benzo) Oxazin-4-one), 6,6′-ethylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-butylenebis (2-methyl-4H, 3,1- Benzoxazin-4-one), 6,6′-butylenebis (2 Phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2- Phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-sulfonylbis ( 2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-carbonyl Bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 7,7′-methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′- Methylenebis (2-phenyl-4H , 3,1-benzoxazin-4-one), 7,7′-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-ethylenebis (2-methyl-) 4H, 3,1-benzoxazin-4-one), 7,7′-oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-sulfonylbis (2-methyl) -4H, 3,1-benzoxazin-4-one), 7,7'-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7'-bis (2- Methyl-4H, 3,1-benzoxazin-4-one), 6,7′-bis (2-phenyl-4H, 3,1-benzoxazin-4-one, 6,7′-methylenebis (2-methyl) -4H, 3,1-benzoxazin-4-one), 6,7 ' Methylene bis (2-phenyl-4H, 3,1-benzoxazin-4-one), and the like.

The benzotriazole-based ultraviolet absorber is not limited to the following, and examples thereof include 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2H-benzotriazole, 2- [2 '-Hydroxy-5'-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxypropyl) phenyl] -2H-benzotriazole, 2- [2'- Hydroxy-5 '-(methacryloyloxyhexyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-tert-butyl-5'-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2 -[2'-hydroxy-5'-tert-butyl-3 '-(methac Royloxyethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2′-hydroxy-5 ′ -(Methacryloyloxyethyl) phenyl] -5-methoxy-2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-cyano-2H-benzotriazole, 2- [2 '-Hydroxy-5'-(methacryloyloxyethyl) phenyl] -5-tert-butyl-2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-nitro-2H -Benzotriazole and the like.

Among the above compounds, when considering the color tone, a benzoxazinone-based compound which is difficult to be yellowed is preferably used. As an example thereof, a compound represented by the following general formula (1) is more preferably used. It is done.

In the above formula, R represents a divalent aromatic hydrocarbon group, and X ¹ and X ² are each independently selected from hydrogen or the following functional group group, but are not necessarily limited thereto.

Functional group: alkyl group, aryl group, heteroaryl group, halogen, alkoxyl group, aryloxy group, hydroxyl group, carboxyl group, ester group, nitro group Among the compounds represented by the above structural formula, in the present invention, 2,2 ′-(1,4-phenylene) bis [4H-3,1-benzoxazin-4-one] is particularly preferred.

The amount of the ultraviolet absorber to be contained in the coated film of the present invention depends on the thickness of the polyester film and cannot be generally stated, but is usually 0.1 to 10% by weight, preferably 0.2 to 3% by weight. %, More preferably 0.3 to 2% by weight. When the ultraviolet absorber is less than 0.1% by weight, the ultraviolet ray cannot be sufficiently absorbed, and the liquid crystal is easily deteriorated by the ultraviolet ray transmitted through the polyester film, so that the amount of the ultraviolet absorber exceeding 10% by weight is contained. In such a case, the ultraviolet absorber may bleed out on the surface, which may cause deterioration in surface functionality such as adhesion deterioration.

In the case of a multilayer film, it is preferably at least a three-layer structure, and the ultraviolet absorber is preferably blended in the intermediate layer. By blending an ultraviolet absorber in the intermediate layer, the compound can be prevented from bleeding out to the film surface, and as a result, properties such as film adhesion can be maintained. A three-layer structure is preferable from the viewpoint that stable production can be achieved even in a multilayer structure.

In order to prevent deterioration of the liquid crystal and the like due to ultraviolet rays by the coated film of the present invention, the light transmittance at a wavelength of 380 nm is 10% or less, preferably 5% or less, more preferably 2% or less, as a measure of the amount of ultraviolet rays. If it is 1% or less, it is a very preferable state. The light transmittance at a wavelength of 380 nm can be adjusted by changing the type and amount of the above-described ultraviolet absorber.

In the polyester layer of the film of the present invention, it is preferable to blend particles for the main purpose of imparting slipperiness and preventing scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples include inorganic particles such as magnesium, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

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

The average particle diameter of the particles is usually 0.01 to 5 μm, preferably 0.01 to 3 μm. If the average particle size is less than 0.01 μm, the slipperiness may not be sufficiently imparted, or the particles may be aggregated to make the dispersibility insufficient, thereby reducing the transparency of the film. On the other hand, when the thickness exceeds 5 μm, the surface roughness of the film becomes too rough, and a problem may occur when various surface functional layers are applied in a subsequent process.

Further, the particle content in the polyester layer is usually 0.0001 to 5% by weight, preferably 0.0003 to 3% by weight. When the particle content is less than 0.0001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

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

Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

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

The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed as a film, but is usually 10 to 300 μm, preferably 25 to 250 μm.

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

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

Next, the formation of the coating layer constituting the coating film in the present invention will be described. Regarding the coating layer, it may be provided by in-line coating which treats the film surface during the process of forming a polyester film, or offline coating which is applied outside the system on a once produced film may be adopted. Since the coating can be performed simultaneously with the film formation, the production can be handled at a low cost, and therefore in-line coating is preferably used.

Although the in-line coating is not limited to the following, for example, in the sequential biaxial stretching, a coating treatment can be performed particularly before the lateral stretching after the longitudinal stretching is finished. When the coating layer is provided on the polyester film by in-line coating, it is possible to apply at the same time as the film formation, and the coating layer can be processed at a high temperature in the heat treatment process of the polyester film after stretching. Performances such as adhesion to various surface functional layers that can be formed on the layer and heat-and-moisture resistance can be improved. Moreover, when coating before extending | stretching, the thickness of an application layer can also be changed with a draw ratio, and compared with offline coating, thin film coating can be performed more easily. That is, a film suitable as a polyester film can be produced by in-line coating, particularly coating before stretching.

In the present invention, at least one surface of a polyester film containing an ultraviolet absorber has a coating layer formed from a coating solution containing a metal oxide (A) and two or more types of crosslinking agents (B), It is an essential requirement to have a coating layer having one minimum value in the wavelength range of 400 to 800 nm and having an absolute reflectance of 4.0% or more at the minimum value. is there.

The metal oxide in the present invention is mainly used for adjusting the refractive index of the coating layer. In particular, since the refractive index of the resin used in the coating layer is low, it is preferable to use a metal oxide having a high refractive index, and it is preferable to use a refractive index of 1.7 or more. Specific examples of the metal oxide include, for example, zirconium oxide, titanium oxide, tin oxide, yttrium oxide, antimony oxide, indium oxide, zinc oxide, antimontin oxide, indium tin oxide, and the like. You may use 2 or more types. Among these, zirconium oxide and titanium oxide are more preferably used. In particular, zirconium oxide is more preferably used from the viewpoint of weather resistance.

The metal oxide is preferably used in the form of particles because there is a concern that the adhesion may be lowered depending on the use form, and the average particle size is preferably 100 nm or less, more preferably from the viewpoint of transparency. It is 50 nm or less, more preferably 25 nm or less.

In the present invention, the coating liquid for forming the coating layer contains two or more types of crosslinking agents, but these have adhesion with a surface functional layer such as a hard coat layer provided on the coating layer. Can be improved. We have found that even one type of cross-linking agent can improve adhesion, but by using two or more types of cross-linking agents together, it is possible to further improve the adhesion, particularly improving the adhesion after the wet heat test. I found that I can do it.

Examples of the crosslinking agent in the present invention include oxazoline compounds, epoxy compounds, melamine compounds, isocyanate compounds, carbodiimide compounds, metal chelate compounds, and silane coupling compounds. Among these crosslinking agents, from the viewpoint of good adhesion, it is particularly preferable to use an oxazoline compound or an epoxy compound, and it is more preferable to use an oxazoline compound and an epoxy compound in combination.

An oxazoline compound is a compound having an oxazoline group in the molecule. In particular, a polymer containing an oxazoline group is preferable, and it can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition-polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like, and one or a mixture of two or more thereof can be used. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not particularly limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, (Meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, Examples of the alkyl group include unsaturated amides such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc .; vinyl acetate Vinyl esters such as 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, vinylidene chloride and vinyl fluoride And α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or more of these monomers can be used.

An epoxy compound is a compound having an epoxy group in the molecule. Examples include condensates of epichlorohydrin with hydroxyl groups and amino groups such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A, and polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. is there. 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. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m-xylyl. Examples include range amine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and a mixture thereof can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

The isocyanate compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of isocyanates include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, lactam compounds such as ε-caprolactam and δ-valerolactam , Amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, formaldehyde, acetal Examples include oxime compounds such as dooxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more.

In addition, the isocyanate compound in the present invention may be used alone or as a mixture or combination with various polymers. In the sense of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

A carbodiimide-based compound is a compound having a carbodiimide or carbodiimide derivative structure, and improves adhesion with a surface functional layer such as a hard coat layer that can be formed on the coating layer, and improves the heat and moisture resistance of the coating layer. It is used for. The carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule, but a polycarbodiimide compound having two or more in the molecule is more preferable for better adhesion and the like.

The carbodiimide compound can be synthesized by a conventionally known technique, and generally a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited, and any of aromatic and aliphatic compounds can be used. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexa Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

Furthermore, in order not to lose the effect of the present invention, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, adding a surfactant, polyalkylene oxide, quaternary ammonium salt of dialkylamino alcohol, You may add and use hydrophilic monomers, such as a hydroxyalkyl sulfonate.

These cross-linking agents are used in a design that improves the performance of the coating layer by reacting in the drying process or film forming process. It can be inferred that unreacted products of these crosslinking agents, compounds after the reaction, or mixtures thereof exist in the finished coating layer.

In the coated film of the present invention, various improvements are made to improve the coated surface, reduce interference unevenness when various surface functional layers such as a hard coat layer are laminated on the coated surface, and improve transparency and adhesion. It is preferable to use a polymer of

Specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches. Etc. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of improving adhesion with a surface functional layer such as a hard coat layer and improving the appearance of coating. In addition, a polyester resin is particularly preferable from the viewpoint that a large number of aromatic compounds such as a benzene ring can be contained in the molecule, thereby increasing the refractive index.

Furthermore, in order to make it easier to adjust the refractive index of the coating layer, naphthalene, anthracene, phenanthrene, naphthacene, benzo [a] anthracene, benzo [a] phenanthrene, pyrene, benzo [c It is preferable to use a compound having a condensed polycyclic aromatic structure such as phenanthrene or perylene.

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

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

In the coated film manufacturing process, the condensed polycyclic aromatic contained in the coating layer is preferably a compound having a naphthalene skeleton in that it is difficult to be colored. In addition, a resin in which a naphthalene skeleton is incorporated as a polyester component is suitably used in terms of good adhesion to various surface functional layers formed on the coating layer and transparency. Representative examples of the naphthalene skeleton include 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.

In addition to the hydroxyl group and the carboxylic acid group, the condensed polycyclic aromatic has a refractive index of a refractive index by introducing a substituent containing a sulfur element, an aromatic substituent such as a phenyl group, a halogen element group, and the like. Improvements can be expected, and substituents such as alkyl groups, ester groups, and amide groups may be introduced from the viewpoints of coatability and adhesion.

Further, in the present invention, the coating layer may contain particles other than the above-described metal oxide for the purpose of improving the adhesion and slipperiness of the coating layer. The average particle diameter is preferably 1.0 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.2 μm or less from the viewpoint of the transparency of the film. Specific examples of the particles include silica, alumina, kaolin, calcium carbonate, and organic particles.

Furthermore, as long as it does not impair the gist of the present invention, the coating layer has an antifoaming agent, a coating property improving agent, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, an antioxidant, foaming as necessary. Agents, dyes, pigments and the like may be contained.

The content of the metal oxide (A) in the coating solution is usually 3 to 70% by weight, preferably 5 to 50% by weight, more preferably 5 to 40% by weight, and particularly preferably 8% as a ratio to the total nonvolatile components. ~ 30% by weight. When the amount of the metal oxide is less than 3% by weight, the refractive index of the coating layer cannot be made sufficiently high, so that interference unevenness may not be reduced. When it exceeds 70% by weight, the coating layer is transparent. Sexuality may worsen.

The content of the two or more kinds of crosslinking agents (B) in the coating solution is usually 2 to 80% by weight, more preferably 4 to 60% by weight, and further preferably 10 to 40% by weight as a ratio to the total nonvolatile components. is there. If it is out of these ranges, if there is a possibility that the adhesion with the surface functional layer such as the hard coat layer may be lowered, or if the coated surface condition deteriorates, the surface functional layer such as the hard coat layer is formed. Visibility may not be good due to uneven interference.

When an oxazoline compound is used as a crosslinking agent, the content of the oxazoline compound in the nonvolatile component of the coating solution is usually 1 to 50% by weight, more preferably 1 to 30% by weight, and further preferably 3 to 20% by weight. . If the amount is less than 1% by weight, there is a concern that the adhesion to the surface functional layer such as a hard coat layer may be lowered. If the amount exceeds 50% by weight, the refractive index of the coating layer is lowered, thereby causing a hard coat layer or the like. Visibility may not be good due to interference unevenness after the surface functional layer is formed.

When an epoxy compound is used as the crosslinking agent, the content of the epoxy compound in the non-volatile component of the coating solution is usually 1 to 50% by weight, more preferably 3 to 30% by weight, and still more preferably 5 to 20% by weight. is there. When it is out of these ranges, there is a possibility that the adhesion with the surface functional layer such as the hard coat layer may be lowered, or the coated surface state may be deteriorated.

In the condensed polycyclic aromatic compound that can be used in the coating layer constituting the coated film in the present invention, the proportion of the condensed polycyclic aromatic compound in the compound is usually 5 to 80% by weight, preferably 10 to 60%. % By weight. The content of the condensed polycyclic aromatic compound in the nonvolatile component of the coating solution is usually 80% by weight or less, preferably 5 to 70% by weight, and more preferably 10 to 50% by weight. By using within these ranges, the refractive index of the coating layer can be easily adjusted, and interference unevenness after forming a surface functional layer such as a hard coat layer can be easily reduced. The ratio of the condensed polycyclic aromatic can be determined by, for example, dissolving and extracting the coating layer with an appropriate solvent or warm water, separating by chromatography, analyzing the structure by NMR or IR, and further pyrolyzing GC-MS (gas It can be determined by analysis by chromatography mass spectrometry) or optical analysis.

In the polyester film of the present invention, a coating layer can also be provided on the surface opposite to the surface on which the coating layer is provided. For example, when forming a functional layer such as a microlens layer, a prism layer, an anti-sticking layer, a light diffusion layer, a hard coat layer, an adhesive layer, or a print layer on the opposite side of forming a surface functional layer such as a hard coat layer, Adhesion with the functional layer can be improved. A conventionally well-known thing can be used as a component of the coating layer formed in the surface on the opposite side. Examples thereof include binder polymers such as polyester resins, acrylic resins and urethane resins, cross-linking agents such as oxazoline compounds, epoxy compounds, melamine compounds and isocyanate compounds, and these materials may be used alone or in combination. May be used in combination. Further, it may be a coating layer (a coating layer having the same surface on both sides of the polyester film) containing a metal oxide, a compound derived from an oxazoline compound, and a compound derived from an epoxy compound as described above.

The analysis of the components in the coating layer can be performed, for example, by analysis of TOF-SIMS, ESCA, fluorescent X-rays and the like.

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

Regarding the coated film in the present invention, the thickness of the coated layer provided on the polyester film is usually 0.04 to 0.20 μm, preferably 0.07 to 0.15 μm. When the film thickness is out of the above range, visibility may deteriorate due to interference unevenness after the surface functional layer is laminated.

In the present invention, as a method of providing the coating layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used.

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

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

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

The coating layer in the present invention has a refractive index adjusted to suppress the occurrence of interference unevenness, and the refractive index (1.55-1.65) is the polyester film (refractive index) of the substrate. : 1.60 to 1.70) and S (refractive index of 1.45 to 1.65) in the vicinity of the geometric mean of the hard coat layer and the like. The refractive index of the coating layer and the reflectance of the coating layer are closely related. For the absolute reflectance of the present invention, a graph showing the wavelength on the horizontal axis and the reflectance on the vertical axis is drawn, and the minimum value of the reflectance needs to be one in the wavelength range of 400 to 800 nm, and the minimum value is 4 0.0% or more. In the absolute reflectance range of the present invention, if the minimum value appears at the same wavelength, the reflectance of the minimum value is a high value when the refractive index is high, and a low value when the refractive index is low.

In the present invention, the absolute reflectance has one minimum value in the wavelength range of 400 to 800 nm, more preferably one minimum value in the wavelength range of 500 to 700 nm. The minimum value is usually 4.0 to 6.5%, preferably 4.5 to 6.2%. If the minimum value in the wavelength range of 400 to 800 nm is not one, and if the absolute reflectance of the minimum value is outside the above value, interference unevenness occurs after the surface functional layer such as the hard coat layer is formed. The visibility of the film may be reduced.

In the present invention, a film having high transparency is more preferred for use in applications requiring transparency such as for displays. For example, haze is mentioned as one index of transparency, and the value is usually 1.5% or less, preferably 1.2% or less, and more preferably 1.0% or less. When the haze is high, the visibility of the film may be lowered.

The polyester film of the present invention is generally provided with a surface functional layer such as a hard coat layer on the coating layer. Although it does not specifically limit as a material used for a hard-coat layer, For example, hardened | cured materials, such as reactive silicon compounds, such as monofunctional (meth) acrylate, polyfunctional (meth) acrylate, and tetraethoxysilane, are mentioned. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an ultraviolet curable polyfunctional (meth) acrylate is particularly preferable.

The composition containing an ultraviolet curable polyfunctional (meth) acrylate is not particularly limited. For example, a mixture of one or more known ultraviolet curable polyfunctional (meth) acrylates, those commercially available as ultraviolet curable hard coat materials, or other than those that do not impair the purpose of this embodiment, What added the other component further can be used.

The UV-curable polyfunctional (meth) acrylate is not particularly limited. For example, dipentaerythritol hexa (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, (Meth) acryl derivatives of polyfunctional alcohols such as trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,6-bis (3-acryloyloxy-2-hydroxypropyloxy) hexane And polyethylene glycol di (meth) acrylate and polyurethane (meth) acrylate.

Other components contained in the composition containing an ultraviolet curable polyfunctional (meth) acrylate are not particularly limited. Examples thereof include inorganic or organic fine particles, polymerization initiators, polymerization inhibitors, antioxidants, antistatic agents, dispersants, surfactants, light stabilizers, and leveling agents. In addition, when the film is dried after film formation in the wet coating method, an arbitrary amount of solvent can be added.

As a method for forming the hard coat layer, when an organic material is used, a general wet coat method such as a roll coat method or a die coat method is employed. The formed hard coat layer can be subjected to a curing reaction by heating, irradiation with active energy rays such as ultraviolet rays and electron beams as necessary. The refractive index of the surface functional layer formed on the coating layer is generally 1.45 to 1.65 as described above.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. The measurement method and evaluation method used in the present invention are as follows.

(1) Measuring method of intrinsic viscosity of polyester:
1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added and dissolved, and measurement was performed at 30 ° C.

(2) Measuring method of average particle diameter:
The coating layer was observed using TEM (“H-7650” acceleration voltage 100 V manufactured by Hitachi High-Technologies Corporation), and the average value of the particle size of 10 particles was defined as the average particle size.

(3) Coating layer thickness measurement method:
The surface of the coating layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method was stained with RuO ₄ , and the cross section of the coating layer was measured using TEM (H-7650 manufactured by Hitachi High-Technologies Corporation, acceleration voltage 100 V).

(4) Evaluation method of absolute reflectance from coating layer surface in polyester film:
A black tape (vinyl tape VT-50 manufactured by Nichiban Co., Ltd.) is pasted on the measurement film back of the polyester film in advance, and a spectrophotometer (UV-spectrophotometer “V-570” manufactured by JASCO Corporation) and an automatic absolute reflectance measuring device. "ARM-500N"), the wavelength range on the coating layer surface under the conditions of synchronous mode, incident angle 5 °, N polarization, response fast, data acquisition interval 1.0 nm, bandwidth 10 nm, scanning speed 1000 m / min The absolute reflectance at 300 to 800 nm was measured, and the wavelength (bottom wavelength) and reflectance at the minimum value were evaluated.

(5) Haze measurement method:
Measurement was performed according to JIS K 7136 using a haze meter HM-150 manufactured by Murakami Color Research Laboratory.

(6) Interference unevenness evaluation method:
On the coating layer side of the polyester film, 72 parts by weight of dipentaerythritol hexaacrylate, 18 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, 10 parts by weight of antimony pentoxide, a photopolymerization initiator (trade name: “Irgacure 184” Ciba A mixed coating solution of 1 part by weight (made by Specialty Chemicals) and 200 parts by weight of methyl ethyl ketone was applied so as to have a dry film thickness of 5 μm and cured by irradiation with ultraviolet rays to form a hard coat layer. The obtained film is visually observed under a three-wavelength light area type fluorescent lamp, and interference unevenness is observed. A when interference unevenness cannot be confirmed is A, when thin sparse interference unevenness is confirmed, B is thin but linear. The case where the interference unevenness was confirmed was C, and the case where the clear interference unevenness was confirmed was D.

(7) Evaluation method of adhesion:
In order to evaluate the tighter adhesion, the materials obtained by removing antimony pentoxide from the hard coat liquid used in the evaluation of the above (5) were examined. That is, 80 parts by weight of dipentaerythritol hexaacrylate, 20 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, 5 parts by weight of a photopolymerization initiator (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals), and 200 parts by weight of methyl ethyl ketone The coating liquid was applied so as to have a dry film thickness of 5 μm and cured by irradiating with ultraviolet rays to form a hard coat layer. The obtained film was subjected to 10 × 10 cross-cut after 100 hours in an environment of 80 ° C. and 90% RH, and then a 18 mm wide tape (cello tape (registered trademark) CT manufactured by Nichiban Co., Ltd.) -18) is attached, and the peeled surface is observed after abrupt peeling at a 180 degree peel angle. When the peeled area is less than 3%, A is 3% or more and less than 10%, and B is 10%. If it is less than 50%, it is C, and if it is 50% or more, it is D.

(8) Measurement of transmittance at a wavelength of 380 nm:
Using a spectrophotometer (UV-3100PC type, manufactured by Shimadzu Corporation), the light transmittance was measured continuously at a low scanning speed, a sampling pitch of 2 nm, and a wavelength range of 300 to 700 nm, and the light transmittance at a wavelength of 380 nm was measured. Detected.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After adding 0.04 part by weight of ethyl acid phosphate to this reaction mixture, 0.04 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (A) was 0.63.

<Method for producing polyester (B)>
In the method for producing polyester (A), after adding 0.04 part by weight of ethyl acid phosphate, 0.2 part by weight of silica particles dispersed in ethylene glycol having an average particle size of 1.6 μm and 0.04 part of antimony trioxide are obtained. A polyester (B) was obtained using the same method as the production method of the polyester (A) except that the polycondensation reaction was stopped at a time corresponding to the intrinsic viscosity of 0.65 by adding parts by weight. The obtained polyester (B) had an intrinsic viscosity of 0.65.

<Method for producing polyester (C)>
The polyester (A) was subjected to a vented twin screw extruder and 2,2 ′-(1,4-phenylene) bis [4H-3,1-benzoxazin-4-one] (manufactured by CYTEC Co., Ltd.) as an ultraviolet absorber. “CYASORB UV-3638” molecular weight 369) was supplied to a concentration of 10% by weight, melt-kneaded to form chips, and an ultraviolet absorbent master batch polyester (C) was prepared. The intrinsic viscosity of the obtained polyester (C) was 0.59.

Examples of compounds constituting the coating layer are as follows.
(Compound example)
Metal oxide: (IA) Zirconium oxide particles having an average particle diameter of 15 nm Metal oxide: (IB) Titanium oxide particles having an average particle diameter of 15 nm

・ Oxazoline compounds: (IIA)
Acrylic polymer “Epocross WS-500” having an oxazoline group and a polyalkylene oxide chain (manufactured by Nippon Shokubai Co., Ltd., containing about 38% by weight of 1-methoxy-2-propanol solvent)
・ Oxazoline compounds: (IIB)
Acrylic polymer “Epocross WS-700” having an oxazoline group and a polyalkylene oxide chain (manufactured by Nippon Shokubai Co., Ltd., VOC free type)

Epoxy compound: (IIIA) “Denacol EX-521” (manufactured by Nagase ChemteX Corporation), which is polyglycerol polyglycidyl ether.
Epoxy compound: (IIIB) “Denacol EX-1410” which is an epoxy resin (manufactured by Nagase ChemteX Corporation).

・ Condensed polycyclic aromatic polyester resin: (IVA)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 80/20 (mol%)
・ Polyester resin: (IVB)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4-butanediol / diethylene glycol = 56/40/4 // 70/20/10 (mol%)
Acrylic resin: (IVC) Aqueous dispersion of acrylic resin polymerized with the following composition: ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) Emulsion polymer (emulsifier: anionic surfactant)
・ Urethane resin (IVD)
“Hydran AP-40”, a carboxylic acid water-dispersed polyester polyurethane resin (manufactured by DIC Corporation)

・ Hexamethoxymethylmelamine (V)

・ Particles: (VIA) Silica particles with an average particle size of 0.07 μm ・ Particles: (VIB) Silica particles with an average particle size of 0.15 μm

Example 1:
A mixed raw material in which polyesters (A) and (B) are mixed at a ratio of 90% and 10%, respectively, is used as a raw material for the outermost layer (surface layer), and polyesters (A) and (C) are respectively at a ratio of 90% and 10%. Each of the mixed raw materials is fed to two extruders as a raw material for the intermediate layer, melted at 285 ° C., and then two types and three layers (surface layer / intermediate layer / A non-stretched sheet was obtained by coextrusion and cooling and solidification in a layer configuration of (surface layer = 1: 18: 1 discharge amount). Next, the film was stretched 3.4 times in the longitudinal direction at a film temperature of 85 ° C. using the difference in peripheral speed of the roll, and then the coating liquid 1 shown in Table 1 below was applied to both sides of the longitudinally stretched film, and led to a tenter. Polyester with a thickness of 100 μm having a coating layer with a coating layer thickness of 0.10 μm after stretching by 4.0% at 120 ° C. in the transverse direction and heat treatment at 225 ° C. A film was obtained.

When the absolute reflectance of the obtained polyester film was measured, the minimum value was 600 nm, and the reflectance was 4.2%. The film after laminating the hard coat layer had no clear interference unevenness, good adhesion, low haze, and good transparency. Moreover, the transmittance | permeability in 380 nm was 0.4%, and it has confirmed that it was absorbing the ultraviolet-ray. The properties of this film are shown in Table 2 below.

Examples 2 to 21:
In Example 1, it manufactured similarly to Example 1 except having changed the coating agent composition into the coating agent composition shown in Table 1, and obtained the polyester film. As shown in Table 2, the finished polyester film had high reflectivity, good interference unevenness level, and good adhesion.

Example 22:
A mixed raw material obtained by mixing polyester (A) and (B) at a ratio of 90% and 10%, respectively, is used as a raw material for the outermost layer (surface layer), and polyesters (A) and (C) are at a ratio of 94% and 6%, respectively. Using the mixed raw material mixed as the raw material for the intermediate layer, co-extrusion with a layer configuration of two types and three layers (surface layer / intermediate layer / surface layer = 1: 25: 1 discharge amount) and coating composition shown in Table 1 A polyester film was obtained in the same manner as in Example 1 except that the composition was changed to a thickness of 188 μm. The completed polyester film is as shown in Table 2. Further, the transmittance at 380 nm was 0.2%, and it was confirmed that ultraviolet rays were absorbed.

Comparative Examples 1 to 5:
In Example 1, it manufactured similarly to Example 1 except having changed the coating agent composition into the coating agent composition shown in Table 1, and obtained the polyester film. When the finished coating film was evaluated, as shown in Table 2, when clear interference unevenness could be observed, the adhesion was inferior.

Comparative Example 6:
A mixed raw material obtained by mixing polyester (A) and (B) at a ratio of 90% and 10%, respectively, is used as a raw material for the outermost layer (surface layer), and polyester (A) is used as a raw material for the intermediate layer. A polyester film was obtained in the same manner as in Example 1 except that the composition was changed to the coating composition shown in 1. When the finished coated film was evaluated, as shown in Table 2, the transmittance at 380 nm was 87.7%, and it was confirmed that ultraviolet rays were not absorbed.

The film of the present invention, for example, in various optical films that are members of liquid crystal or plasma displays, molding films, etc., for applications that place importance on adhesion and visibility with surface functional layers such as hard coat layers. It can be suitably used.

Claims

A coated film having a coated layer on at least one outermost layer of the polyester film, wherein at least one layer of the polyester film contains an ultraviolet absorber, and the coated layer comprises a metal oxide (A) and an oxazoline compound. , An epoxy compound, a melamine compound, an isocyanate compound, a carbodiimide compound, a metal chelate compound, a coating solution containing two or more kinds of crosslinking agents (B) each selected from the group of silane coupling compounds, and A coated film having one minimum value in the range of 400 to 800 nm in absolute reflectance, and having an absolute reflectance of 4.0% or more at the minimum value.
The ratio of the metal oxide (A) in the coating solution is 3 to 70% by weight, and the content of two or more kinds of crosslinking agents (B) in the coating solution is 2 to 80% by weight as a ratio to the total nonvolatile components. The coated film according to claim 1.
The coated film according to claim 1 or 2, wherein the two or more types of crosslinking agents (B) contain at least an oxazoline compound or an epoxy compound.
The coated film according to claim 1 or 2, wherein the two or more kinds of crosslinking agents (B) contain at least an oxazoline compound and an epoxy compound.
The coated film according to any one of claims 1 to 4, wherein the ultraviolet absorber is a benzoxazinone type.
The coated film according to any one of claims 1 to 5, wherein the metal oxide is zirconium oxide or titanium oxide.
The coated film according to any one of claims 1 to 6, wherein the coating solution further contains a condensed polycyclic aromatic compound.
The coated film according to claim 7, wherein the content of the condensed polycyclic aromatic compound in the coating solution is 80% by weight or less as a ratio to the total nonvolatile components.