JP2016032943A - Laminate polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate polyester film that can be suitably used for various purposes where a high-quality curable resin layer with fewer defects is required, for example, for a backlight unit member of a liquid crystal display.SOLUTION: The laminate polyester film has a coating layer containing particles having an average particle diameter of 0.10 to 1.0 μm by 10 wt.% or more, on one surface of a polyester film, and a curable resin layer on the coating layer, and also has a coating layer containing a polymer and a crosslinking agent, and a curable resin layer, successively on the other surface of the polyester film.SELECTED DRAWING: None

Description

  The present invention relates to a laminated polyester film, for example, a laminated polyester having a curable resin layer such as a backlight unit of a liquid crystal display, a prism layer, a microlens layer, a hard coat layer, an anti-sticking layer, a light diffusion layer, etc. It relates to film.

  In recent years, polyester films have been used in various applications such as liquid crystal display members such as prism sheets, microlens sheets, hard coat films, antireflection films, light diffusion sheets, and electromagnetic wave shielding films. The base film used for these members is required to have excellent transparency and visibility.

  Therefore, the film used for these uses generally has high transparency. However, in order to increase transparency, a flat film design is used. For this reason, the slipperiness of the film is poor, scratches and wrinkles occur in the processing process, and it may be difficult to manufacture a high-quality processed product. Also, because of the high transparency, it is not easy to distinguish between the processed film that has formed the curable resin layer and the unprocessed film before processing, especially when it is in sheet-fed form There is a possibility of mistaken goods and raw products.

  As a transparent base film for forming various functional layers such as a prism layer, a hard coat layer and a light diffusion layer, a polyester film is generally used in consideration of transparency and mechanical properties. In order to improve adhesion to various functional layers, an easily adhesive coating layer is generally provided as the intermediate layer.

JP 2007-55222 A

  The present invention has been made in view of the above circumstances, and the solution is to use a film with high processing characteristics, such as a prism layer, a microlens layer, an anti-sticking layer, and a hard coat layer with few defects. An object of the present invention is to provide a laminated polyester film that has a curable resin layer and can be suitably used as a member such as a backlight unit of a liquid crystal display that requires high quality.

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

That is, the gist of the present invention is to have a coating layer containing 10% by weight or more of particles having an average particle size of 0.10 to 1.0 μm on one surface of a polyester film, and a curable resin on the coating layer. The present invention resides in a laminated polyester film having a layer and sequentially having a coating layer containing a polymer and a crosslinking agent and a curable resin layer on the other surface of the polyester film.

  According to the laminated polyester film of the present invention, a high-quality laminated polyester film with few defects can be provided, and its industrial value is high.

  The polyester film constituting the laminated polyester 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 it does not exceed the gist of the present invention other than a 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, the dicarboxylic acid component of the copolyester includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxybenzoic acid, etc.), etc. 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned.

  There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used, For example, an antimony compound, a titanium compound, a germanium compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned. Among these, titanium compounds and germanium compounds are preferable because they have high catalytic activity, can be polymerized in a small amount, and the amount of metal remaining in the film is small, so that the brightness of the film becomes high. Furthermore, since a germanium compound is expensive, it is more preferable to use a titanium compound.

  In the case of polyester using a titanium compound, the titanium element content is preferably 50 ppm or less, more preferably 1 to 20 ppm, and still more preferably 2 to 10 ppm. If the content of the titanium compound is too high, the polyester may be deteriorated in the process of melt-extruding the polyester, resulting in a strong yellowish film. If the content is too low, the polymerization efficiency is poor and the cost is low. In some cases, a film having a sufficient strength or a sufficient strength cannot be obtained. Moreover, when using the polyester by a titanium compound, it is preferable to use a phosphorus compound in order to reduce the activity of a titanium compound for the purpose of suppressing deterioration in the step of melt extrusion. As the phosphorus compound, orthophosphoric acid is preferable in view of the productivity and thermal stability of the polyester. The phosphorus element content is preferably in the range of 1 to 300 ppm, more preferably 3 to 200 ppm, and still more preferably 5 to 100 ppm with respect to the amount of polyester to be melt-extruded. If the content of the phosphorus compound is too large, it may cause gelation or foreign matter. If the content is too small, the activity of the titanium compound cannot be lowered sufficiently, and the yellowish It may be a film.

  The polyester film of the present invention may contain an ultraviolet absorber in order to improve the weather resistance of the film and to prevent deterioration of the liquid crystal of a liquid crystal display used for a touch panel or the like. 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.

  Examples of the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable. 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.

  In the polyester layer of the film of the present invention, particles can be blended mainly for the purpose of imparting slipperiness and preventing scratches in each step. When the particles are blended, the kind of the particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid. Examples thereof include inorganic particles such as calcium, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium 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. Of these, silica particles are preferred because they are particularly effective in a small amount.

The average particle diameter of the particles is preferably 5 μm or less, more preferably 0.01 to 3 μm. By using the average particle diameter within the above range, an appropriate surface roughness is imparted to the film, and in the case where various curable resin layers and the like are formed in a subsequent process, problems are unlikely to occur.

  Furthermore, the particle content in the polyester layer is preferably less than 5% by weight, more preferably in the range of 0.0003 to 3% by weight. When there are no particles or when there are few particles, the transparency of the film becomes high and a good film is obtained, but care must be taken because slipperiness may be insufficient before the formation of the coating layer. Moreover, when there is too much particle content, even if a curable resin layer is formed, haze will not fully fall, but the transparency of a film may be inadequate.

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 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.

  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 it is preferably 10 to 350 μm, more preferably 20 to 300 μm.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, when producing a biaxially stretched polyester film, the polyester raw material described above is first melt-extruded from a die using an extruder, and the molten sheet is cooled and solidified with a cooling roll to obtain an unstretched sheet. 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 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-stage stretching direction at usually 70 to 170 ° C. and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, a method of obtaining a biaxially oriented film by performing heat treatment at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% can be mentioned. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 270 ° C. under tension or 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, formation of the coating layer which comprises the laminated polyester film in this invention is demonstrated. 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. More preferably, it is formed by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of a polyester to heat setting after stretching and winding up. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to such a method, film formation and coating layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the coating layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily. Further, by providing the coating layer on the film before stretching, the coating layer can be stretched together with the base film, whereby the coating layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer can be improved, and the coating layer and the base film can be more firmly adhered to each other. Furthermore, it can be set as a firm coating layer, and performances such as adhesion to various curable resin layers that can be formed on the coating layer and wet heat resistance can be improved.

  In the present invention, on one surface of the polyester film, a coating layer containing 10% by weight or more of particles having an average particle size of 0.10 to 1.0 μm (hereinafter sometimes referred to as a first coating layer), It is an essential requirement to have a coating layer containing a polymer (hereinafter sometimes referred to as a second coating layer) on the other surface of the polyester film.

  In applications where transparency is highly required, the present inventors are in a direction of decreasing transparency, but dare to contain a large amount of particles in the coating layer, improving the slipperiness of the film, in the post-processing step Prevents scratched defects and wrinkles. As a result of further investigation, according to the coating layer formation according to the present invention using particles of a specific size, by providing a curable resin layer on the first coating layer, the coating layer can contain particles. It has been found that the haze produced can be reduced and a laminated polyester film having good transparency can be obtained. That is, the present inventors have found a method for producing a laminated polyester film having a curable resin layer that has the characteristics of having few scratches and wrinkles while ensuring transparency.

  In addition to the above characteristics, improvements in various characteristics can be expected. By containing 10% by weight or more of particles having an average particle diameter of 0.10 to 1.0 μm, the contact area between the coating layer and the curable resin layer is increased, so that improvement in adhesion between the two layers can be expected. In addition, when a transparent curable resin layer is formed on a transparent substrate, the final product is also transparent, so it is difficult to determine whether it has been processed, but in the present invention, the haze is high and not transparent before processing. Since the film has a low haze and is transparent after processing, there is an added value that it is easy to distinguish between processed and unprocessed. Furthermore, there is an effect of reducing interference unevenness due to external light reflection. Since unevenness due to particles is formed in the coating layer, when the curable resin layer is formed on the coating layer, the curable resin layer enters the concave portion of the coating layer, thereby forming the coating layer and the curable resin layer. Since the boundary region is in the vicinity of the middle of the refractive indexes of both layers, external light reflection is weakened and interference unevenness is reduced.

  As the particles to be contained in the coating layer, various conventionally known particles can be used. For example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, Examples include inorganic particles such as zirconium oxide and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Among them, inorganic particles are preferable in that hardness can be imparted, and silica particles are more preferable in consideration of stability in the state of the coating liquid.

  The average particle size of the particles used in the first coating layer is essential to be 0.10 to 1.0 μm, preferably 0.10 to 0.70 μm, more preferably 0.20 to 0.60 μm, Preferably it is the range of 0.25-0.50 micrometer. By using it in these ranges, the slipperiness of the film becomes good and a high-quality film can be obtained. In addition, there is an advantage that the transparency after forming the curable resin layer on the coating layer is improved, an advantage that it is easy to distinguish between processing and non-processing of the curable resin layer, and particles are dropped from the coating layer. There is also an advantage that blocking of the film can be prevented. Moreover, the range of the boundary region in the thickness direction having a refractive index near the middle between the coating layer and the curable resin layer becomes appropriate, and an effect can be expected to reduce interference unevenness due to reflection of external light.

  In the present invention, the first coating layer preferably contains a polymer. The role of the polymer includes maintaining the above-described particles in the coating layer and improving adhesion with the curable resin layer formed on the first coating layer.

  A conventionally well-known polymer can be used as a polymer. Specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. . Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoints of improving the adhesion with the curable resin layer and improving the coating appearance. In view of compatibility with the polyester film of the base material, a polyester resin is more preferable, and an acrylic resin and a urethane resin are preferable from the viewpoint that adhesion with various curable resin layers is further improved.

  The polyester resin includes, for example, those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and ester-forming derivatives thereof can be used. As the polyvalent hydroxy compound, ethylene Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more compounds may be appropriately selected from these compounds, and a polyester resin may be synthesized by a conventional polycondensation reaction.

  The acrylic resin is a polymer composed of a polymerizable monomer including acrylic and methacrylic monomers. These may be either homopolymers or copolymers, and copolymers with polymerizable monomers other than acrylic and methacrylic monomers. Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Alternatively, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer in a polyurethane solution or a polyurethane dispersion (sometimes a mixture of polymers) is also included. Similarly, a polymer (in some cases, a polymer mixture) obtained by polymerizing a polymerizable monomer in another polymer solution or dispersion is also included. Moreover, in order to improve adhesiveness more, it is also possible to contain a hydroxyl group and an amino group.

  The polymerizable monomer is not particularly limited, but particularly representative compounds include, for example, various carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Monomers, and salts thereof; such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, monobutyl hydroxy itaconate Various hydroxyl group-containing monomers; various (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate; (Meth) acrylamide, Various nitrogen-containing compounds such as acetone acrylamide, N-methylol acrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, and various vinyls such as vinyl propionate Esters; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc .; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and biridene chloride Various conjugated dienes such as butadiene.

  The urethane resin is a polymer compound having a urethane bond in the molecule. Usually, urethane resin is prepared by reaction of polyol and isocyanate. Examples of the polyol include polycarbonate polyols, polyester polyols, polyether polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

  Polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Examples of the polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane. Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, neopentyl glycol, 3-methyl-1,5-pentanediol, 3,3-dimethylol heptane and the like can be mentioned. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of polycarbonate polyols obtained from these reactions include poly (1,6-hexylene) carbonate, poly (3- And methyl-1,5-pentylene) carbonate.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. Product and polyhydric alcohol (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.).

  Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  Among the above polyols, polyester polyols and polycarbonate polyols are more preferably used in order to improve the adhesion with the curable resin layer.

  Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. -Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate, aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanzi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

  A chain extender may be used when synthesizing the urethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. And glycols such as glycols. Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidenecyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1, 3-Bisaminomethylcyclohexa And alicyclic diamines such as

  The urethane resin in the present invention may use a solvent as a medium, but preferably uses water as a medium. In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, a self-emulsification type in which an ionic group is introduced into the structure of a urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance, transparency, and adhesion of the resulting coating layer.

Examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, and a carboxyl group is preferred. As a method for introducing a carboxyl group into a urethane resin, various methods can be taken in each stage of the polymerization reaction. For example, there are a method of using a carboxyl group-containing resin as a copolymer component during prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as polyol, polyisocyanate, and chain extender. In particular, a method in which a desired amount of carboxyl groups is introduced using a carboxyl group-containing diol depending on the amount of this component charged is preferred.
For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid and the like are copolymerized with a diol used for polymerization of a urethane resin. Can do. The carboxyl group is preferably in the form of a salt neutralized with ammonia, amine, alkali metal, inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine. In such a polyurethane resin, a carboxyl group from which the neutralizing agent has been removed in the drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. Thereby, it is possible to further improve the durability, solvent resistance, water resistance, blocking resistance, and the like of the obtained coating layer, as well as excellent stability in a liquid state before coating.

  Moreover, in order to improve the intensity | strength of an application layer, it is preferable to use a crosslinking agent together. A conventionally well-known material can be used with a crosslinking agent, For example, an oxazoline compound, an epoxy compound, an isocyanate type compound, a carbodiimide type compound, a melamine compound, a silane coupling compound, a hydrazide compound, an aziridine compound etc. are mentioned. From the viewpoint of good adhesion, oxazoline compounds, epoxy compounds, isocyanate compounds, and carbodiimide compounds are preferred among the above. Moreover, in order to improve the adhesiveness with the curable resin layer, it is more preferable to use two or more kinds of crosslinking agents in combination. In particular, it has been found that the adhesion is remarkably improved when used in combination of an oxazoline compound and an epoxy compound, an oxazoline compound and an isocyanate compound, an oxazoline compound and a carbodiimide compound, or an isocyanate compound and a carbodiimide compound. In addition, in terms of increasing the strength of the coating layer, it has also been found that it is more preferable to use a melamine compound in combination, especially when the average particle size exceeds 0.2 μm and the particle content exceeds 10% by weight. Proved to be very effective.

  The oxazoline compound is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and 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, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (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, As the alkyl group, unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); 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.

  The content of the oxazoline group contained in the oxazoline compound is usually 0.5 to 10 mmol / g, preferably 1 to 9 mmol / g, more preferably 3 to 8 mmol / g, and further preferably 4 to 6 mmol in terms of the amount of the oxazoline group. / G. Use within the above range is preferable because adhesion to the curable resin layer is improved.

  The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensates of epichlorohydrin with ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and the like hydroxyl groups and amino groups, There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. 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 isocyanate compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of isocyanate 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, acetoald Examples include oxime compounds such as oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more. Among these, an active methylene compound is preferable from the viewpoint that adhesion with the curable resin layer is easily improved.

  In addition, the isocyanate compound in the present invention may be used alone, or may be used as a mixture or bond 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 structure, and is used for improving the adhesion with a curable resin layer that can be formed on a coating layer and for improving the heat-and-moisture resistance of the coating layer. . 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.

  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.

  The content of the carbodiimide group contained in the carbodiimide-based compound is a carbodiimide equivalent (weight of the carbodiimide compound to give 1 mol of carbodiimide group [g]) and is usually 100 to 1000, preferably 250 to 800, more preferably 300. It is -700, More preferably, it is the range of 350-650. Use within the above range is preferable because adhesion to the curable resin layer is improved.

  The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolized melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and these Mixtures 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.

  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.

  Next, the second coating layer of the present invention will be described. The main purpose of the second coating layer is adhesion to the curable resin layer. Therefore, when it is necessary to form a curable resin layer that is more difficult to ensure adhesion, it is preferable to form it on the second coating layer instead of the first coating layer.

  Examples of the polymer contained in the second coating layer include polymers that can be used to form the first coating layer described above. In addition, it is also possible to use a polymer containing a carbon-carbon double bond in order to further improve the adhesion with the active energy ray-curable resin layer among the curable resin layers. From the viewpoint of improving adhesion, examples of the polymer containing a carbon-carbon double bond include a urethane resin, an acrylic resin, and a polyester resin. Further, from the viewpoint of introducing a stable carbon-carbon double bond, a urethane resin is more preferable, and among them, a polyester-based urethane resin formed from a polyester polyol or a polycarbonate-based urethane resin formed from a polycarbonate polyol is particularly preferable. Is preferred. The coating layer contains a carbon-carbon double bond, and the carbon-carbon double bond of the compound used for forming the prism layer, the microlens layer, the hard coat layer, or the like is irradiated with active energy rays. It can be reacted to form a covalent bond, thereby improving adhesion.

  The coating layer formed from the polymer containing a carbon-carbon double bond is usually a curable resin layer using active energy rays among curable resin layers, and in particular, a prism layer or a microlens layer. It is optimal for improving the adhesion with a curable resin layer formed from a solvent-free active energy ray-curable composition, which is generally difficult to ensure adhesion. Particularly in recent years, there is a trend toward lower power consumption, and it is necessary to improve the brightness of the prism sheet and microlens sheet as compared with the prior art. There is a tendency. In order to increase the refractive index of these curable resin layers, a technique using a compound containing a large amount of aromatics has been taken. However, on the other hand, when the aromatic content is increased, there is a problem that the adhesiveness with the coating layer is lowered due to the small interaction. Therefore, there is a demand for a laminated polyester film having a coating layer that can sufficiently ensure adhesion even in a design with a high aromatic content, a high refractive index, that is, a high brightness.

  The urethane resin containing a carbon-carbon double bond is one having a carbon-carbon double bond in a urethane resin, and contained in a compound that forms a prism layer, a microlens layer, a hard coat layer, or the like. Any conventionally known material can be used as long as it reacts with a carbon-carbon double bond. For example, introduction into a urethane resin in the form of an acrylate group, a methacrylate group, a vinyl group, an allyl group or the like can be mentioned.

  Various substituents can be introduced into the carbon-carbon double bond, such as an alkyl group such as a methyl group or an ethyl group, a phenyl group, a halogen group, an ester group, an amide group, or a conjugated double bond. You may have such a structure. Further, the amount of the substituent is not particularly limited, and any of a 1-substituted product, a 2-substituted product, a 3-substituted product, or a 4-substituted product can be used. A 2-substituted product is preferable, and a 1-substituted product is more preferable.

  Considering the ease of introduction into the urethane resin and the reactivity with the carbon-carbon double bond contained in the compound forming the prism layer, microlens layer, hard coat layer, etc., an acrylate group or a methacrylate group is preferable, An acrylate group and a methacrylate group having no group are more preferable, and an acrylate group having no substituent is particularly preferable.

  The ratio of the carbon-carbon double bond part (C = C part, molecular weight 24) to the whole urethane resin is preferably 0.5% by weight or more, more preferably 1.0% by weight or more, and further preferably 1 .5% by weight or more. When the ratio of the carbon-carbon double bond portion to the entire resin is 0.5% by weight or more, adhesion to a prism resin, a microlens resin, a hard coat resin, or the like is effectively improved.

  Also in the second coating layer, it is preferable to use a crosslinking agent in the same manner as in the first coating layer, and the crosslinking agent used is the same as that in the first coating layer. From the viewpoint of good adhesion, oxazoline compounds, epoxy compounds, isocyanate compounds, and carbodiimide compounds are preferred among the above. In order to further improve the adhesion to the curable resin layer, it is more preferable to use two or more kinds of crosslinking agents in combination, and in particular, an oxazoline compound and an epoxy compound, an oxazoline compound and an isocyanate compound, When used in combination with a carbodiimide compound, an isocyanate compound and a carbodiimide compound, the adhesion is remarkably improved.

  Moreover, in order to improve slipperiness and blocking, it is preferable to use particles together in forming the second coating layer. As the kind of particle | grains, the thing similar to the particle | grains used for formation of a 1st application layer can be used. The average particle diameter of the particles is preferably 1.0 μm or less, more preferably 0.02 to 0.70 μm, still more preferably 0.05 to 0.50 μm, particularly preferably 0.10 to 0.30 μm, Most preferably, it is the range of 0.12-0.18 micrometer. By using in these ranges, the film has good slipperiness and is difficult to block. It is also effective in preventing the particles from falling off the coating layer. Furthermore, when particles with a relatively large particle size are used, the contact area increases in the form of the coating layer entering the curable resin layer. When the resin layer is formed, there is also a light diffusing effect, and a film more suitable for a backlight can be obtained.

  Furthermore, as long as it does not impair the gist of the present invention, any coating layer may be formed with an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, an oxidation agent as necessary. It is also possible to use an inhibitor, a foaming agent, a dye, a pigment and the like in combination.

  As a ratio in the 1st coating layer which comprises the laminated polyester film in this invention, it is essential that particle | grains are 10 weight% or more, Preferably it is 12-60 weight%, More preferably, it is 20-50 weight%, Especially. Preferably it is the range of 25-40 weight%. By using within the above range, the slipperiness of the film will be sufficient, defects in the post-processing steps can be reduced, and effective haze adjustment can be made, so that the curable resin layer can be processed or not processed It becomes easy to put on. Further, the range of the boundary region in the surface direction having a refractive index near the middle between the coating layer and the curable resin layer becomes appropriate, and an effect can be expected to reduce interference unevenness due to reflection of external light.

  As a ratio in the 1st application layer which comprises the laminated polyester film in this invention, a polymer becomes like this. Preferably it is 10 to 85 weight%, More preferably, it is 15 to 75 weight%, More preferably, it is the range of 25 to 65 weight%. . By using it in the above range, it is effective for good adhesion and prevention of falling off of particles.

  As a ratio in the 1st coating layer which comprises the laminated polyester film in this invention, the component derived from a crosslinking agent becomes like this. Preferably it is less than 80 weight%, More preferably, it is the range of 5-65 weight%, More preferably, it is 10-50 weight % Range. By using in the said range, it becomes a favorable application | coating external appearance and a firm coating layer, and can form the curable resin layer with favorable adhesiveness. In particular, when it is desired to strengthen the coating layer, it is preferable to use a melamine compound in combination, and a preferable range thereof is 3 to 30% by weight, and more preferably 5 to 20% by weight.

  As a ratio in the second coating layer constituting the laminated polyester film in the present invention, the polymer is preferably 10% by weight or more, more preferably 15 to 90% by weight, still more preferably 25 to 85% by weight, and particularly preferably 40%. It is in the range of -75% by weight. By using in the said range, adhesiveness will become favorable.

  As a ratio in the 2nd coating layer which comprises the laminated polyester film in this invention, the component derived from a crosslinking agent becomes like this. Preferably it is less than 80 weight%, More preferably, it is the range of 3-70 weight%, More preferably, it is 5-60 weight %, Particularly preferably in the range of 10 to 45% by weight. By using in the said range, it becomes a favorable application | coating external appearance and a firm coating layer, and can form the curable resin layer with favorable adhesiveness.

  As a ratio in the second coating layer constituting the laminated polyester film in the present invention, the particles are preferably less than 70% by weight, more preferably 3 to 60% by weight, still more preferably 10 to 50% by weight, and particularly preferably 15%. It is in the range of ˜40% by weight. By using in the said range, the slipperiness of a film will become sufficient and the fine diffusion by curable resin layer formation will become effective.

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

  Regarding the formation of the coating layer, the above-described series of compounds is used as a solution or solvent dispersion, and the coating solution adjusted with a solid content concentration of about 0.1 to 80% by weight as a guide is laminated on the polyester film. It is preferred to produce a polyester film. In particular, when the coating layer is provided by in-line coating, an aqueous solution or a water dispersion is more preferable, but a small amount of an organic solvent is added to the coating solution for the purpose of improving the dispersibility in water and improving the film forming property. You may contain. Moreover, only one type of organic solvent may be used, and two or more types may be used as appropriate.

  Regarding the laminated polyester film in the present invention, the thickness of the coating layer provided on the polyester film is usually in the range of 0.001 to 1 μm, preferably 0.01 to 0.5 μm, more preferably 0.03 to 0.2 μm. It is. By using the film thickness in the above range, it is effective in preventing the particles from falling off, and good coating appearance and adhesion with the curable resin layer can be ensured.

  The relationship between the average particle diameter of the particles and the film thickness of the coating layer is preferably in the range of 1.0 or more, more preferably in the range of 1.2 to 20, as the average particle diameter / film thickness of the coating layer. Preferably it is the range of 1.5-15, Most preferably, it is the range of 1.7-10. By using in the said range, it can raise as a laminated polyester film which provided the application layer, and haze fall after providing a curable resin layer can be performed effectively. In addition, it is possible to contribute to preventing the particles from falling off the coating layer.

  In the film of the present invention, as a method for forming the coating layer, for example, gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze Conventionally known coating methods such as coating, impregnation coating, kiss coating, spray coating, calendar coating, extrusion coating, etc. 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, the heat treatment is usually performed at 70 to 270 ° C. for 3 to 200 seconds. good.

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

  In order to reduce defects such as scratches and wrinkles during processing of the curable resin layer, it is preferable that the coating layer has good slipperiness. The coefficient of static friction can be cited as an index of slipperiness. It is possible to adjust by the average particle diameter and content of the particles contained in the coating layer. The range of the coefficient of static friction is preferably 0.7 or less, more preferably 0.1 to 0.6, and still more preferably 0.2 to 0.5. By using in these ranges, the slipping property of the film becomes an optimum range for processing of the curable resin layer, and it is possible to prevent the occurrence of defects such as scratches and wrinkles. Moreover, it is also possible to reduce the point-like defect which generate | occur | produces because the slipperiness when it makes it roll shape is bad.

  In order to easily distinguish between processing and non-processing of the curable resin layer, it is preferable that the haze is reduced by forming the curable resin layer on the first coating layer. The amount of haze reduction is not particularly limited, but is preferably 1.0% or more, more preferably 3.0% or more, still more preferably 5.0% or more, particularly preferably 7.0% or more, and most preferably 10%. % Or more. By setting the above range, it becomes easy to distinguish between processing and non-processing of the curable resin layer according to various places such as a conference room, a work room, an inspection room, and a view of the film.

  Although the haze of the polyester film which has a coating layer before forming the curable resin layer of this invention is not specifically limited, Preferably it is 3.0% or more. When adjusting the haze with particles, the appearance of the film depends on the type and size of the particles used and the state of the substrate, but it cannot be said unconditionally, but the curable resin layer is not processed or processed. In order to make distinction easier, it is more preferably more than 5.0%, still more preferably more than 10%, and particularly preferably more than 15%.

  In the present invention, it is an essential requirement to have a curable resin layer on the first coating layer and the second coating layer. Examples of the curable resin layer include a prism layer, a microlens layer, a hard coat layer, an anti-sticking layer, and a light diffusion layer.

  The curable resin layer formed on the first coating layer is not particularly limited. However, in the present invention, the anti-sticking layer, the hard coat layer, or the low haze is generally low. A haze (8.0% or less) light diffusion layer or the like is preferable, and the haze of the curable resin layer is preferably 8.0% or less, more preferably 3.0% or less, and even more preferably 1.0% or less. Especially preferably, it is 0.5% or less of range. As the curing type, both thermal curing and active energy ray curing are good. The thickness of the curable resin layer is not particularly limited, but is preferably 0.1 to 50 μm, more preferably 1 to 15 μm, and still more preferably 1 to 8 μm.

  On the other hand, as a curable resin layer formed on a 2nd application layer, it is preferable as a total film design to arrange | position a layer with less adhesiveness than the curable resin layer formed on a 1st application layer. Although not particularly limited, a prism layer, a microlens layer, and the like can be given. Since these curable resin layers usually do not contain a solvent or are formed from a compound of 5% by weight or less even if contained, there is a tendency that the penetration into the coating layer is weak and the adhesion is poor. In particular, since the prism layer and the microlens layer designed for increasing the brightness as in recent years have poor adhesion, the second coating layer of the present invention is effective. As the type of curing, active energy ray curing is more preferable than thermal curing.

  That is, a preferable configuration in the present invention is curable resin layer / first coating layer / polyester film / second coating layer / active energy ray curable resin layer, and particularly preferably (anti-sticking layer, hard coat). Or a curable resin layer selected from a low-haze light diffusion layer) / first coating layer / polyester film / second coating layer / (prism layer or microlens layer).

  As an example of the curable resin layer, in the case of a hard coat layer, the material used is not particularly limited, but for example, reactive silicon such as monofunctional (meth) acrylate, polyfunctional (meth) acrylate, tetraethoxysilane, etc. Examples include cured products such as compounds. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an active energy ray-curable (meth) acrylate is particularly preferable.

  The composition containing the active energy ray-curable (meth) acrylate is not particularly limited. For example, a mixture of one or more known active energy ray-curable monofunctional (meth) acrylates, bifunctional (meth) acrylates, polyfunctional (meth) acrylates, and commercially available as an active energy ray-curable hard coat resin material In addition, those other than these may be used as long as the object of the present embodiment is not impaired.

  The active energy ray-curable monofunctional (meth) acrylate is not particularly limited. For example, methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) ) Acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, alkyl (meth) acrylate such as isobornyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc. Alkyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, etc. Amino group-containing (meth) acrylates such as aromatic (meth) acrylates such as coxyalkyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, diaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, Methoxyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, ethylene oxide modified (meth) acrylate such as phenylphenol ethylene oxide modified (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Examples include (meth) acrylic acid.

  The active energy ray-curable difunctional (meth) acrylate is not particularly limited, and for example, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, alkanediol di (meth) acrylate such as tricyclodecane dimethylol di (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate Bisphenol F ethylene oxide modified di (meth) acrylate and other bisphenol modified di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, urethane di (meth) acrylate And epoxy di (meth) acrylate.

  The active energy ray-curable polyfunctional (meth) acrylate is not particularly limited, and examples thereof include dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate. , Pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ε-caprolactone modified tris (acryloxyethyl) isocyanurate Acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urea Down prepolymers, urethane acrylates such as dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, and the like.

  Other components contained in the composition containing the active energy ray-curable (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 a curable resin layer such as a hard coat layer, a general wet coat method such as a roll coat method or a die coat method is adopted when an organic material is used. 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.

  Examples of the curable resin layer include a prism layer and a microlens layer which are solvent-free curable resin layers. In recent years, various shapes have been proposed for the prism layer in order to improve the luminance efficiently. Generally, prism layers are formed by arranging prism rows having a triangular cross section in parallel. Similarly, various shapes of the microlens layer have been proposed, but in general, a large number of hemispherical convex lenses are provided on the film. Any layer can have a conventionally known shape.

  Examples of the shape of the prism layer include a triangular cross section having a thickness of 10 to 500 μm, a pitch of prism rows of 10 to 500 μm, and an apex angle of 40 ° to 100 °. Examples of the shape of the microlens layer include a hemispherical shape having a thickness of 10 to 500 μm and a diameter of 10 to 500 μm, but may have a shape such as a cone or a polygonal pyramid.

  The prism layer and the microlens layer are generally composed of an active energy ray-curable compound that is solvent-free (the solvent content is 5% by weight or less, more preferably 3% by weight or less, and even more preferably no solvent is contained). It is formed. The hard coat layer is generally formed from a solvent-based active energy ray-curable compound.

  Examples of the compound that forms the prism layer and the microlens layer include the compounds used in the formation of the hard coat layer described above. Furthermore, in order to increase the brightness, it is preferable to use a material that can increase the refractive index.

  The refractive index of the prism layer and the microlens layer for increasing the brightness is preferably 1.57 or more. In the laminated polyester film of the present invention, the higher the refractive index, the more the luminance tends to improve. In the present invention, the refractive index of the polyester film is around 1.65. Therefore, the refractive index range of the active energy ray-curable resin layer such as the prism layer or the microlens layer is usually 1.57 to 1.65, Preferably it is 1.58-1.64, More preferably, it is the range of 1.59-1.63. By setting it within the above range, the luminance can be increased.

  In order to make the refractive index within the above range, a method using a compound having a large aromatic structure, a sulfur atom, a halogen atom, or a metal compound in addition to the general compound described above can be used. Among them, a method using a compound having a large aromatic structure or a sulfur atom is particularly preferable from the viewpoint of the environment because the refractive index of the prism layer and the microlens layer can be made uniform.

  Examples of the compound having a large aromatic structure include condensed polycyclic aromatic structures such as naphthalene, anthracene, phenanthrene, naphthacene, benzo [a] anthracene, benzo [a] phenanthrene, pyrene, benzo [c] phenanthrene, and perylene. , A compound having a biphenyl structure, a compound having a fluorene structure, and the like.

  Various substituents may be introduced into the condensed polycyclic aromatic structure, biphenyl structure, and fluorene structure. Particularly, those having a benzene ring-containing substituent such as a phenyl group have a higher refractive index. Since it can be made high, it is preferable. It is also possible to introduce atoms that increase the refractive index, such as sulfur atoms and halogen atoms. Furthermore, various functional groups such as an ester group, an amide group, a hydroxyl group, an amino group, and an ether group can be introduced in order to improve the adhesion with the coating layer.

  The total of the condensed polycyclic aromatic structure, the biphenyl structure, the fluorene structure and the aromatic compound substituted in these structures in the active energy ray-curable resin layer in the film of the present invention is the type and amount of other structures, or Since it depends on the curing condition, it cannot be generally stated, but it is preferably 20 to 80% by weight, more preferably 25 to 70% by weight, still more preferably 30 to 60% by weight, based on the entire ultraviolet curable resin layer. It is a range. By using in the above range, it is possible to form a curable resin layer having high luminance.

  The ratio of the compound having a condensed polycyclic aromatic structure, biphenyl structure, and fluorene structure forming the active energy ray-curable resin layer in the film of the present invention is the total nonvolatile content of the compound composition forming the active energy ray-curable resin layer. As a ratio with respect to a component, it is 10 weight% or more normally, Preferably it is 20 to 90 weight%, More preferably, it is the range of 25 to 80 weight%. By using in the above range, it is possible to form a curable resin layer having high luminance.

  In addition, as an example of the curable resin layer, the anti-sticking layer and the light diffusion layer contain particles and a binder. The anti-sticking layer contains the same binder and particles as the light diffusion layer, and the content of the particles is not intended to be light diffusive. Therefore, a method of containing a smaller amount with a smaller particle size is generally used. It is.

  As particles to be included in the anti-sticking layer and the light diffusion layer, conventionally known particles can be used. Organic particles such as acrylic resin, acrylic urethane resin, urethane resin, polyester resin, and polyvinyl resin, silica, metal oxide And inorganic particles such as barium sulfate can be used. Of these, acrylic resins and acrylic urethane resins having good transparency are preferably used. The particle size of these particles is not particularly limited, but is 1 to 50 μm, more preferably 1 to 10 μm as an average particle size.

  The binder contained in the anti-sticking layer or the light diffusion layer is used to fix the particles. For example, polyester resin, acrylic resin, polyurethane resin, fluororesin, silicone resin, epoxy resin, the hard coat layer described above Examples thereof include active energy ray-curable resins similar to those used for the formation of. In consideration of processability, a polyol compound is preferably used, and examples thereof include acrylic polyol and polyester polyol.

  When a polyol compound is used as a binder, it is preferable to contain isocyanate as a curing agent. By containing isocyanate, a stronger crosslinked structure can be formed, and physical properties as a thermosetting resin layer are improved. Moreover, when using an active energy ray curable resin as a binder, (meth) acrylate type resin is preferable, and it can be used for the improvement of the hardness of a curable resin layer.

  If necessary, the anti-sticking layer and the light diffusion layer may contain a surfactant, a fine inorganic filler, a plasticizer, a curing agent, an antioxidant, an ultraviolet absorber, a rust inhibitor, and the like.

  The mixing ratio of the binder and the particles in the anti-sticking layer and the light diffusion layer can be appropriately set depending on the characteristics to be obtained, and is not particularly limited. For example, the binder / particles are 0.1 to 50 by weight ratio. The range is more preferably 0.5 to 20.

  Examples of the method for forming the anti-sticking layer and the light diffusion layer include a method in which a coating liquid containing a binder and particles is prepared, applied and dried. As a coating method, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, spray coating, spin coating or the like can be used. The thickness of the anti-sticking layer or the light diffusion layer is not particularly limited, but it is in the range of 1 to 100 μm, more preferably in the range of 1 to 30 μm in consideration of light diffusibility, film strength, and the like.

  The analysis of the components of the curable resin layer can be performed by analysis such as TOF-SIMS, ESCA, fluorescent X-ray, and NMR.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Method for measuring the intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. And dissolved at 30 ° C.

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

(3) Weight of carbon-carbon bond part in polymer After the polymer was dried under reduced pressure, each peak of ¹ H and ¹³ C was assigned using NMR (AVANCE III600 manufactured by Bruker Biospin) and obtained by calculation.

(4) Method for measuring film thickness of coating layer The surface of the coating layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by ultramicrotomy stained with RuO _4, a coating layer cross-section was measured by using a TEM (Hitachi High Technologies Corporation H-7650, accelerating voltage 100 V). The film thickness was measured at a location not including the particle portion.

(5) Measuring method of refractive index The curable composition used for formation of a curable resin layer was arrange | positioned flat with a film thickness of 10 micrometers on the application layer, it was made to harden | cure, and the flat curable resin layer was formed. The refractive index of the curable resin layer side was measured using a refractometer (SL-NA-B manufactured by Atago Co., Ltd.).

(6) Friction coefficient measurement method A film is pasted on a smooth glass plate having a width of 10 mm and a length of 100 mm with the first coating layer side as an upper surface, and the first of a film cut out to a width of 18 mm and a length of 120 mm. With the coating layer side as the bottom surface, press against a metal pin with a diameter of 8 mm so that the coating layer sides rub against each other, and slide the metal pin in the longitudinal direction of the glass plate at a load of 30 g and 40 mm / min to measure the frictional force. Then, the coefficient of friction (static coefficient of friction) at the point where sliding began was measured. The measurement was performed in an atmosphere of room temperature 23 ± 1 ° C. and humidity 50 ± 0.5% RH, and when the friction coefficient was high and the measured runout was large, the intermediate value of the runout was taken as the friction coefficient.

(7) Measuring method of haze It measured by JISK7136 using the haze meter HM-150 by Murakami Color Research Laboratory.

(8) Method of measuring haze reduction when forming curable resin layer on first coating layer After forming a curable resin layer only on the first coating layer of the film, haze is applied by the method according to (6). The difference from the haze before forming the curable resin layer was measured.

(9) Discrimination evaluation method before and after curable resin layer processing The difference between the 20 cm × 20 cm film before and after the curable resin layer was formed on the first coating layer was observed. As a method of observation, assuming a conference room and an examination room, the film on which a curable resin layer is not formed and cured on two places on a white desk (discrimination 1) and on a black desk (discrimination 2) The difference between the two was confirmed when the film on which the conductive resin layer was formed was placed and observed from a location 1 m away at an angle of 30 degrees. 5 points if the difference can be discriminated instantaneously, 4 points if it can be easily discriminated by observation for 3 seconds, 3 points if it can be discriminated if you look carefully, 2 points if it is difficult to discriminate, 1 point if it cannot be discriminated did. A higher score is preferred.

(10) Method for evaluating adhesion between first coating layer and curable resin layer A film having a curable resin layer formed on the first coating layer was treated for 50 hours in an environment of 80 ° C. and 90% RH. A 10 × 10 cross cut is applied to the curable resin layer of the subsequent film, and an 18 mm wide tape (Cello Tape (registered trademark) CT-18, manufactured by Nichiban Co., Ltd.) is applied thereon, and the peel angle is 180 degrees. When the peeled area is less than 5%, ◎ if the peeled area is less than 5%, ◯ if it is 5% or more and less than 10%, Δ if it is 10% or more and less than 50%, and x if it is 50% or more. .

(11) Method for evaluating adhesion between second coating layer and curable resin layer A film having a curable resin layer formed on the second coating layer was treated for 50 hours in an environment of 80 ° C. and 90% RH. The curable resin layer of the subsequent film is scratched at 5 mm intervals with a cutter knife, and an 18 mm wide tape (Cello Tape (registered trademark) CT-18 manufactured by Nichiban Co., Ltd.) is applied, and suddenly at a peeling angle of 180 degrees. I did. The peeled surface was observed. If the peeled area was less than 5%, ◎ was marked if it was 5% or more but less than 20%, Δ if it was 20% or more and less than 50%, and x if it was 50% or more.

(12) Luminance Evaluation Method Using a luminance measuring device (BM-7 manufactured by Topcon Co., Ltd.), the luminance is measured, and the case where the luminance is improved by 2% or more compared to Comparative Example 5 is improved. However, the case where it was less than 2% was rated as ◯, and the case where it was equal to or less than was rated as x.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, 30 ppm of ethyl acid phosphate with respect to the resulting polyester, and 100 ppm of magnesium acetate tetrahydrate with respect to the resulting polyester as the catalyst at 260 ° C. in a nitrogen atmosphere at 260 ° C. The reaction was allowed to proceed. Subsequently, 50 ppm of tetrabutyl titanate was added to the resulting polyester, the temperature was raised to 280 ° C. over 2 hours and 30 minutes, the pressure was reduced to 0.3 kPa in absolute pressure, and melt polycondensation was further carried out for 80 minutes. 0.63 polyester (A) was obtained.

<Method for producing polyester (B)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, and magnesium acetate tetrahydrate as a catalyst were subjected to an esterification reaction at 225 ° C. in a nitrogen atmosphere at 900 ppm with respect to the produced polyester. Subsequently, 3500 ppm of orthophosphoric acid was added to the produced polyester, and 70 ppm of germanium dioxide was added to the produced polyester. The temperature was raised to 280 ° C. over 2 hours and 30 minutes, and the pressure was reduced to an absolute pressure of 0.4 kPa. After 85 minutes of melt polycondensation, polyester (B) having an intrinsic viscosity of 0.64 was obtained.

<Method for producing polyester (C)>
In the production method of the polyester (A), the polyester (C) is produced using the same method as the production method of the polyester (A) except that 0.3 part by weight of silica particles having an average particle diameter of 2.7 μm is added before the melt polymerization. Got.

Examples of compounds constituting the coating layer are as follows.
(Example compounds)
Particles: (IA) Silica particles with an average particle size of 0.15 μm Particles: (IB) Silica particles with an average particle size of 0.20 μm Particles: (IC) Silica particles with an average particle size of 0.30 μm Particles: (ID ) Silica particles with an average particle size of 0.45 μm

・ Polyester resin: (IIA)
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: (IIB) 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 with carbon-carbon double bond: (IIC)
Hydroxyethyl acrylate unit: dicyclohexylmethane diisocyanate unit: hexamethylene diisocyanate trimer unit: caprolactone unit: ethylene glycol unit: dimethylolpropanoic acid unit = 18: 12: 22: 26: 18: 4 (mol%) A urethane resin having a carbon-carbon double bond weight of 2.0% by weight.

-Urethane resin with carbon-carbon double bond: (IID)
Hydroxyethyl acrylate unit: dicyclohexylmethane diisocyanate unit: hexamethylene diisocyanate trimer unit: caprolactone unit: ethylene glycol unit: dimethylolpropanoic acid unit = 6: 10: 20: 38: 22: 4 (mol%) A urethane resin having a carbon-carbon double bond weight of 0.7% by weight.

・ Oxazoline compounds: (IIIA)
Acrylic polymer having an oxazoline group and a polyalkylene oxide chain Epocross (Oxazoline group amount = 4.5 mmol / g, manufactured by Nippon Shokubai Co., Ltd.)

Epoxy compound: (IIIB) polyglycerol polyglycidyl ether

・ Isocyanate compounds: (IIIC)
1000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium capryate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction, and an isocyanurate type polyisocyanate composition was obtained. 100 parts of the obtained isocyanurate type polyisocyanate composition, 42.3 parts of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts of propylene glycol monomethyl ether acetate were charged and maintained at 80 ° C. for 7 hours. Thereafter, the reaction solution temperature was kept at 60 ° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 part of 28% methanol solution of sodium methoxide were added and kept for 4 hours. Block polyisocyanate obtained by adding 58.9 parts of n-butanol, maintaining the reaction solution temperature at 80 ° C. for 2 hours, and then adding 0.86 part of 2-ethylhexyl acid phosphate.

・ Carbodiimide compounds: (IIID)
Polycarbodiimide compound Carbodilite (carbodiimide equivalent = 600, manufactured by Nisshinbo Co., Ltd.)

Melamine compound: (IIIE) hexamethoxymethylol melamine

Examples of compounds constituting the curable resin layer are as follows.
(Example compounds)
・ UV curable compounds: (ia)
2-biphenoxyethyl acrylate
・ UV curable compound: (ib)
4,4 ′-(9-fluorenylidene) bis (2-phenoxyethyl acrylate)
・ UV curable compound: (ic)
Ethylene glycol modified bisphenol A acrylate (ethylene glycol chain = 8)
・ UV curable compound: (id)
Ethylene glycol modified bisphenol A acrylate (ethylene glycol chain = 10)
・ UV curable compounds: (ie)
Hexanediol diacrylate / photopolymerization initiator: (ii)
Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide

Example 1:
A mixed raw material in which polyesters (A), (B), and (C) were mixed in proportions of 91%, 3%, and 6%, respectively, was used as a raw material for the outermost layer (surface layer), and polyesters (A) and (B) were each 97 %, 3% of the mixed raw material is used as an intermediate layer raw material, each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C. Coextruded with a layer structure of layers (surface layer / intermediate layer / surface layer = 1: 14: 1 discharge amount) and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.3 times in the machine direction at a film temperature of 85 ° C. using the roll peripheral speed difference, and then the coating liquid A1 shown in Table 1 below was applied on one side of the longitudinally stretched film to the thickness of the coating layer (dried) (After) is applied so as to be 0.11 μm (first coating layer), and coating liquid B2 is applied to the opposite surface so that the thickness of the coating layer (after drying) is 0.04 μm (second). The coated layer was led to a tenter, stretched 3.9 times at 120 ° C. in the transverse direction, heat treated at 225 ° C., and relaxed 2% in the transverse direction to obtain a polyester film having a thickness of 250 μm.

  As a curable resin layer on the first coating layer of the obtained polyester film, 88 parts by mass of resin (Halus Hybrid UV-G301, manufactured by Nippon Shokubai Co., Ltd.), isocyanate (manufactured by Sumika Bayer Urethane Co., Ltd., Death Module N-3200) ) 9 parts by mass, 3 parts by mass of acrylic resin particles having an average particle size of 5 μm (MBX-15 manufactured by Sekisui Plastics Co., Ltd.), 100 parts by mass of toluene, and 100 parts by mass of methyl ethyl ketone are prepared and applied and heat cured. A film having a 3 μm thick anti-sticking layer (having a haze of the layer of 0.4%, hereinafter sometimes referred to as S1) was obtained.

  Next, as a curable resin layer on the second coating layer, a composition P1 shown in Table 3 below is applied to a mold member in which a large number of prism rows having a pitch of 50 μm and an apex angle of 65 ° are arranged in parallel to form a prism layer. Place the laminated polyester film so that the second coating layer of the film obtained above comes into contact with the composition from above, stretch the composition uniformly with a roller, and irradiate ultraviolet rays from an ultraviolet irradiation device to cure I let you. Next, the film was peeled off from the mold member to obtain a film on which a prism layer (hereinafter sometimes referred to as P1) was formed.

  When the obtained film was evaluated, it was a coating layer having a low coefficient of friction and good slipperiness, so there were no scratches or wrinkle defects, and the processing / unprocessed discrimination of the anti-sticking layer, adhesion and prism layer Adhesion and brightness were good. The properties of this film are shown in Tables 4 and 5 below.

Examples 2 to 165, 176 to 185, 196 to 205, 216 to 225:
In Example 1, the coating composition was changed to the coating composition shown in Tables 1 and 2, and the compound composition of the curable resin layer formed on the second coating layer was changed as shown in Table 3. 1 to obtain a laminated polyester film. As shown in Tables 4 to 15, the finished laminated polyester film was a coating layer having a low coefficient of friction and good slipperiness, so there were no scratches or wrinkle defects, and processing / unprocessed discrimination of the anti-sticking layer, and The adhesion and luminance of the prism layer were good.

Examples 166-175, 186-195, 206-215:
In Example 1, a film on which a coating layer was formed was obtained in the same manner as in Example 1 except that the coating composition was changed to the coating composition shown in Tables 1 and 2. As a curable resin layer on the first coating layer of the obtained film, 84 parts by mass of dipentaerythritol hexaacrylate, 8 parts by mass of 2-hydroxy-3-phenoxypropyl acrylate, acrylic resin particles having an average particle size of 5 μm (sekisui MBX-15 manufactured by Seisaku Kogyo Co., Ltd. 3 parts by weight, photopolymerization initiator (Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd.) 5 parts by weight, 100 parts by weight toluene, 100 parts by weight methyl ethyl ketone were prepared, applied and dried, and ultraviolet light. Was cured by irradiation to obtain a film on which a 3 μm thick anti-sticking layer (the haze of the layer is 0.4%, hereinafter may be referred to as S2) is formed. Next, a film on which a prism layer was formed was obtained in the same manner as in Example 1 except that the compound composition of the curable resin layer formed on the second coating layer was changed as shown in Table 3.

  When the obtained film was evaluated, it was a coating layer having a low coefficient of friction and good slipperiness, so there were no scratches or wrinkle defects, and the processing / unprocessed discrimination of the anti-sticking layer, adhesion and prism layer Adhesion and brightness were good. The characteristics of this film are shown in Tables 10-13 below.

Example 226:
A mixed raw material in which polyesters (A) and (B) are mixed at a ratio of 97% and 3%, respectively, is used as a raw material for the outermost layer (surface layer), and polyesters (A) and (B) are respectively at a ratio of 97% and 3%. 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 3.3 times in the machine direction at a film temperature of 85 ° C. using the roll peripheral speed difference, and then the coating liquid A5 shown in Table 1 below was applied to one side of the longitudinally stretched film with the film thickness (dried) (After) is applied so as to be 0.11 μm (first coating layer), and coating liquid B2 is applied to the opposite surface so that the thickness of the coating layer (after drying) is 0.10 μm (second) The coated layer was led to a tenter, stretched 3.9 times at 120 ° C. in the transverse direction, heat treated at 225 ° C., and relaxed 2% in the transverse direction to obtain a polyester film having a thickness of 250 μm. A curable resin layer was formed on both sides in the same manner as in Example 1 on the resulting polyester film coating layer.

  When the obtained film was evaluated, it was a coating layer having a low coefficient of friction and good slipperiness, so there were no scratches or wrinkle defects, and the processing / unprocessed discrimination of the anti-sticking layer, adhesion and prism layer Adhesion and brightness were good. The properties of this film are shown in Tables 14 and 15 below.

Comparative Example 1:
In Example 1, it manufactured similarly to Example 1 except having not provided the application layer, and obtained the polyester film. When the finished polyester film was evaluated, as shown in Table 17 below, the coefficient of friction was high, the slipping property of the coating layer was poor, and the processing / unprocessed discrimination and adhesion of the anti-sticking layer were also poor.

Comparative Examples 2-5:
In Example 1, the coating composition was changed to the coating composition shown in Tables 1 and 2, and the compound composition of the curable resin layer formed on the second coating layer was changed as shown in Table 3. 1 and a polyester film was obtained. When the finished polyester film was evaluated, as shown in Tables 16 and 17 below, it was found that the sticking prevention layer was poorly processed / unprocessed, the friction coefficient was high, and the slipping property of the coating layer was not sufficient. .

  The film of the present invention can be suitably used for applications requiring a high-quality curable resin layer with few defects, such as a backlight unit of a liquid crystal display.

Claims (4)

The polyester film has a coating layer containing 10% by weight or more of particles having an average particle size of 0.10 to 1.0 μm on one surface of the polyester film, and has a curable resin layer on the coating layer. A laminated polyester film comprising a coating layer containing a polymer and a crosslinking agent and a curable resin layer in this order on the other surface. The laminated polyester film according to claim 1, wherein two or more kinds of crosslinking agents are contained in the coating layer containing a polymer and a crosslinking agent. The laminated polyester film according to claim 1 or 2, wherein the polymer contained in the coating layer containing a polymer and a crosslinking agent is a polymer containing a carbon-carbon double bond. The laminated polyester film according to any one of claims 1 to 3, wherein the haze of the polyester film having the coating layer before forming the curable resin layer is 3.0% or more.