JP6528809B2 - Laminated polyester film - Google Patents

Description

  The present invention relates to a laminated polyester film, and, for example, processed and unprocessed functional layers in applications such as backlight units for liquid crystal displays, functional layers such as sticking prevention layers, hard coat layers and light diffusion layers, etc. The present invention relates to a laminated polyester film suitable to facilitate the distinction of

In recent years, polyester films are used in various applications of liquid crystal display members, such as anti-sticking films, hard coat films, light diffusion sheets, prism sheets, microlens sheets, antireflection films, electromagnetic wave shielding films, etc. .
Base films used for these members are required to have excellent transparency and visibility.

  Therefore, films having high transparency are generally used for these applications. However, since the transparency is high, it is not possible to easily distinguish between the processed film on which various functional layers are formed and the unprocessed film before processing, especially when it is made in sheet-fed form. There was a possibility that the product and the raw product could be mistaken.

  A polyester film is generally used in view of transparency and mechanical properties as a transparent base film for forming an anti-sticking layer, a hard coat layer or a light diffusion layer, and the polyester film of the base and the anti-sticking layer or In order to improve the adhesion to the diffusion layer, it is generally the case that an easily adhesive coated layer is provided as the intermediate layer.

JP 2007-55222 A

  This invention is made in view of the said situation, Comprising: The problem to be solved is processing of a functional layer, for example, in the use which forms functional layers, such as an anti-sticking layer, a hard-coat layer, and a light-diffusion layer with low haze. -To provide an excellent laminated polyester film to facilitate the distinction of raw.

  MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in view of the said situation, the present inventors discover that the above-mentioned subject can be easily solved if the lamination polyester film which consists of a specific structure is used, and came to complete this invention.

That is, the gist of the present invention is a polyester film having a coating layer containing particles on at least one side thereof for providing and using a functional layer on the coating layer, and the functional layer is formed on the coating layer. , reduced haze 1.0% or more, average particle diameter of the particles is in the range of 0.01 to 1.0 [mu] m, the thickness of the coating layer, wherein the range der Rukoto of 0.03~1μm It exists in the laminated polyester film to be.

  According to the laminated polyester film of the present invention, haze is greatly reduced by forming various functional layers such as a sticking prevention layer, a hard coat layer, a light diffusion layer having a low haze, etc., and the distinction between processed and unprocessed functional layers It is possible to provide a substrate film that can be easily applied, 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 in addition to the two-layer and three-layer structure, four or more layers unless the gist of the present invention is exceeded. It may be multi-layered, and is not particularly limited.

  The polyester used in the present invention may be homopolyester or copolyester. When it consists of homo polyesters, what is obtained by polycondensing aromatic dicarboxylic acid and aliphatic glycol is 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. A polyethylene terephthalate etc. are illustrated as a typical polyester. On the other hand, as the dicarboxylic acid component of the copolyester, isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-hydroxybenzoic acid etc.), etc. 1 type, or 2 or more types are mentioned, 1 or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4- cyclohexane dimethanol, neopentyl glycol etc. are mentioned as a glycol component.

  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 film has high brightness. Furthermore, it is more preferable to use a titanium compound because the germanium compound is expensive.

  In the case of a polyester using a titanium compound, the titanium element content is preferably 50 ppm or less, more preferably 1 to 20 ppm, still more preferably 2 to 10 ppm. When the content of the titanium compound is too large, deterioration of the polyester may be promoted in the step of melt extruding the polyester, and a film having a strong yellow color may be obtained. When the content is too small, the polymerization efficiency is poor and the cost is low. In some cases, a film having up or sufficient strength can not be obtained. Moreover, when using 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 the deterioration suppression in the process of melt-extrusion. As the phosphorus compound, orthophosphoric acid is preferable in consideration of the productivity and the thermal stability of the polyester. The phosphorus content is preferably in the range of 1 to 300 ppm, more preferably 3 to 200 ppm, still more preferably 5 to 100 ppm, based on the amount of polyester to be melt-extruded. If the content of the phosphorus compound is too high, it may cause gelation or foreign matter, and if the content is too low, the activity of the titanium compound can not be sufficiently lowered, and the yellowish It may be a film.

  The polyester film of the present invention may also contain an ultraviolet absorber for the purpose of improving the weather resistance of the film and preventing the deterioration of the liquid crystal of the liquid crystal display used in touch panels and the like. The ultraviolet absorber is not particularly limited as long as it is a compound that absorbs ultraviolet light and can withstand the heat added in the production process of the polyester film.

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

  In the polyester layer of the film of the present invention, it is also possible to incorporate particles mainly for the purpose of imparting slipperiness and preventing the occurrence of flaws in each step. In the case of blending particles, the type of particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and as specific examples, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid 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 can be mentioned. Furthermore, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used in the polyester production process. Among these, silica particles are preferred in that they are particularly effective in small amounts.

  The average particle diameter of the particles is usually 5 μm or less, preferably in the range of 0.01 to 3 μm. When the average particle size exceeds 5 μm, the surface roughness of the film becomes too rough, and problems may occur when forming various functional layers and the like in the subsequent steps.

  Furthermore, the particle content in the polyester layer is usually less than 5% by weight, preferably in the range of 0.0003 to 3% by weight. If there are no or few particles, the transparency of the film will be high and it will be a good film, but it may become slippery, so putting the particles in the coated layer makes it slippery. In some cases, improvements such as improvement are required. When the content is more than 5% by weight, the haze may not be sufficiently lowered even if the functional layer is formed, and the transparency of the film may be insufficient.

The shape of the particles to be used is not particularly limited, and any of spherical, massive, rod-like, flat 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 needed.

  It does not specifically limit as method to add particle | grains in a polyester layer, A conventionally well-known method can be employ | adopted. For example, although it can be added at any stage of producing the polyester constituting each layer, it is preferably added after completion of the esterification or transesterification reaction.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, heat 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 the film can be formed as a film, but is usually 10 to 350 μm, 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, first, the polyester raw material described above is melt extruded from a die using an extruder, and the molten sheet is cooled and solidified by a cooling roll to obtain an unstretched sheet. In this case, in order to improve the planarity of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and the electrostatic application adhesion method or the liquid application adhesion method is preferably employed. Next, the unstretched sheet obtained is stretched in one direction by a roll or 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 at a stretching ratio of usually 2.5 to 7 times, preferably 3.0 to 6 times, usually at 70 to 170 ° C., in a direction perpendicular to the first stage stretching direction. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In said extending | stretching, the method of performing extending | stretching of one direction in two or more steps is also employable. In that case, it is preferable to carry out so that the draw ratio of two directions finally becomes the said range, respectively.

  Further, in the present invention, a simultaneous biaxial stretching method can also be adopted for producing a polyester film constituting a laminated polyester film. The simultaneous biaxial stretching method is a method of simultaneously stretching and orienting the above-mentioned unstretched sheet in the machine direction and the width direction in a state where the temperature is usually controlled at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in area ratio. Then, heat treatment is subsequently performed at a temperature of 170 to 270 ° C. under tension or relaxation within 30% to obtain a stretched and oriented film. With respect to the simultaneous biaxial stretching apparatus adopting the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

  Next, formation of the coating layer which comprises the laminated polyester film in this invention is demonstrated. With regard to the coated layer, an in-line coating may be provided to treat the film surface during the film forming process of the polyester film, or an off-line coating may be employed which is applied outside the film on the film once produced. More preferably, it is formed by in-line coating.

  In-line coating is a method of coating in the process of polyester film production, and more specifically, a method of coating at any stage from melt extrusion of polyester to stretching, heat setting and winding up. Usually, the unstretched sheet obtained by melting and quenching, the stretched uniaxially stretched film, the biaxially stretched film before heat setting, and the film after heat setting and before winding are coated. Although not limited to the following, for example, in the sequential biaxial stretching, a method of stretching in the transverse direction after coating on a uniaxially stretched film stretched particularly in the longitudinal direction (longitudinal direction) is excellent. According to this method, since film formation and application layer formation can be performed simultaneously, there is a merit on the manufacturing cost, and in order to perform stretching after coating, the thickness of the application layer can be changed by the stretching ratio. Thin film coating can be performed more easily than offline coating. 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 the biaxially stretched polyester film, the film can be restrained in the longitudinal and transverse directions by holding the film end with a clip or the like while stretching, and in the heat setting step, no wrinkles or the like occur and the plane is flat. High temperature can be applied while maintaining the sex. Therefore, since the heat treatment applied after application can be performed at a high temperature which can not be achieved by other methods, the film forming property of the applied layer can be improved, and the applied layer and the substrate film can be more firmly adhered. Furthermore, it is possible to form a strong coating layer, and to improve performance such as adhesion to various functional layers that may be formed on the coating layer, and moisture and heat resistance.

  In the present invention, when the coating layer is provided and the functional layer is formed on the coating layer, it is an essential requirement that the haze be reduced by 1.0% or more.

  The film of the present invention is designed to make it easy to distinguish between processed and unprocessed functional layers by lowering the haze after forming the functional layers such as the anti-sticking layer, the hard coat layer and the light diffusion layer with low haze. .

  When the functional layer is formed on the coating layer, in order to reduce the haze by 1.0% or more, it is preferable to set the haze of the laminated polyester film having the coating layer before forming the functional layer high. It is possible to adjust from both the haze of the polyester film of a base material and the haze of a coating layer. In order to increase the haze, for example, there is a method in which particles are contained in a substrate or a coating layer to diffuse light. Although it depends on the refractive index of the particles, it can not generally be said, but generally, the larger the particle size and the larger the amount, the higher the haze tends to be. Therefore, the haze can be adjusted by changing the particle size and the amount according to the purpose.

  When the functional layer is formed on the coating layer, in order to reduce the haze, it is effective to reduce the surface unevenness formed by the polyester film of the substrate or the coating layer by forming the functional layer. . The formation of the surface asperities is possible both from the design of the polyester film of the substrate and the design of the coated layer, as in the case of the adjustment of the film haze. When adjusting by the design of the polyester film of a base material, it is made a multilayer structure, for example, the method of making particles contain in the outermost polyester film layer by the side of an application layer (the side which forms a functional layer) rather than the middle layer of polyester film. Is preferred because it is easy to form surface irregularities. Moreover, the method of forming surface asperity mainly formed the surface unevenness by the adjustment by the design of the coating layer which is in direct contact with the functional layer, ie, the outermost layer of the laminated polyester film of the present invention, by the adjustment by the design of the substrate. It is more preferable because the haze reduction at the time of becoming becomes efficient.

  As a method of forming surface asperity which a haze reduces by a functional layer, the method of containing particle | grains, and the method of making unevenness in the coating layer itself are mentioned, for example. As a method of forming irregularities on the coating layer itself, a method of forming a coating layer by mixing polymers having poor stability so as to form a coating layer, or coating a polymer having poor stretching following property, film stretching process And a method of forming a coating layer. In consideration of the stability of the haze value by the production, the solution stability of the coating solution, and the like, a method in which particles are contained in the coating layer is preferable. In particular, according to the method in which particles are contained in the coating layer, blocking and slipperiness can be improved, which is preferable. In addition, the surface area of the coating layer is increased, which also contributes to the improvement of the adhesion to the functional layer.

  As particles to be contained in the coating layer, conventionally known various 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 they can impart hardness, and silica particles are more preferable in consideration of the stability in the state of the coating liquid. In addition, metal oxides are also preferable in that light scattering is large and the haze is easily increased because the difference in refractive index with the polymer used to hold the particles in the coating layer is large.

  The average particle diameter of the particles used for the coating layer depends on the film thickness of the coating layer and can not be generally mentioned, but generally 0.01 to 1.0 μm, preferably 0.05 to 0.8 μm, More preferably, it is in the range of 0.1 to 0.7 μm, particularly preferably 0.2 to 0.5 μm.

  In the present invention, the coating layer contains an acrylic resin. As a role of acrylic resin, holding the particle | grains mentioned above in a coating layer and improving adhesiveness with the various functional layers which may be formed on a coating layer are mentioned. Furthermore, acrylic resins are generally low refractive index materials. Because of the low refractive index, it also has the advantage that it is also possible to design the total light transmittance of the laminated polyester film to be high. By increasing the total light transmittance, it becomes easy to detect defects such as foreign matter in the film, and in applications where the quality is severe, films with few defects can be sorted out by inspection to provide a higher quality film. It becomes possible.

  The acrylic resin is a polymer composed of a polymerizable monomer having a carbon-carbon double bond, as represented by acrylic and methacrylic monomers. These may be homopolymers or copolymers. Also included are copolymers of these polymers with other polymers such as polyesters, polyurethanes and the like. For example, a block copolymer and a graft copolymer. Alternatively, a polyester solution or a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester dispersion is also included. Also included are polyurethane solutions, polymers obtained by polymerizing polymerizable monomers having carbon-carbon double bonds in polyurethane dispersion (in some cases, mixtures of polymers). Similarly, other polymer solutions, or polymers obtained by polymerizing polymerizable monomers having carbon-carbon double bonds in a dispersion (in some cases, a polymer mixture) are 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 having a carbon-carbon double bond is not particularly limited, but as typical compounds, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic Various carboxyl group-containing monomers such as acids, and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, Various hydroxyl group containing monomers such as monobutyl hydroxyitaconate; Various kinds such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate ( Meta) acrylic esters; Various nitrogen-containing compounds such as acrylamide, diacetone acrylamide, N-methylol acrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, vinyl propionate Various vinyl esters such as: various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane and the like; phosphorus-containing vinyl-based monomers; various kinds such as vinyl chloride and vinylidene chloride Halogenated vinyls of the following: various conjugated dienes such as butadiene. It is also possible to use an acrylic resin having a fluorine atom introduced to increase the total light transmittance.

  In forming the coating layer in the film of the present invention, it is also possible to use various polymers other than the acrylic resin in combination for the coating appearance, the adjustment of the haze, the retention of particles and the like.

  As the polymer, conventionally known polymers can be used, and specific examples thereof include polyester resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl chloride copolymer, etc.), polyalkylene glycol, polyalkylene Imimine, methylcellulose, hydroxycellulose, starches etc. are mentioned. Among these, polyester resins and urethane resins are preferable if used in combination, from the viewpoint of improving the adhesion with various functional layers and improving the coating appearance.

  With polyester resin, what consists of a polyvalent carboxylic acid and a polyvalent hydroxy compound as follows as a main structural component is mentioned, for example. That is, as polyvalent carboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acids, succinic acids, trimellitic acids, trimesic acids, pyromellitic acids, trimellitic anhydrides, phthalic anhydrides, p-hydroxybenzoic acids, trimellitic acid monopotassium salts and their ester-forming derivatives can be used. And ethylene as polyvalent hydroxy compounds Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanedio- , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol And polytetramethylene glycol, polytetramethylene oxide glycol, dimethylol propionic acid, glycerin, trimethylol propane, sodium dimethyl ethyl sulfonate, potassium dimethyl propionate and the like can be used. Among these compounds, one or more may be appropriately selected, and a polyester resin may be synthesized by a polycondensation reaction in a conventional manner.

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

  As polyester polyols, polyvalent carboxylic 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 And polyhydric alcohols (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 Those obtained from the reaction of a diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamines, lactone diols, etc.), those having a derivative unit of a lactone compound such as polycaprolactone, etc. may be mentioned.

  Polycarbonate polyols are obtained from polyhydric alcohols and carbonate compounds by a dealcoholization reaction. As polyhydric alcohols, 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-dimethylolheptane and the like can be mentioned. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate and the like. Polycarbonate polyols obtained from these reactions include, for example, poly (1,6-hexylene) carbonate, poly (3- (3) Methyl-1,5-pentylene) carbonate and the like can be mentioned.

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

  Among the above-mentioned polyols, polyester polyols and polycarbonate polyols are more preferably used in order to improve adhesion to various functional layers.

  As polyisocyanate compounds used to obtain urethane resins, aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, α, α, α ′, α ′ Aliphatic diisocyanates having an aromatic ring such as tetramethyl xylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, aliphatic diisocyanates such as trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methane diy Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination of two or more.

  When synthesizing a urethane resin, a chain extender may be used, and as the chain extender, there is no particular limitation as long as it has two or more active groups that react with isocyanate groups, generally, hydroxyl groups Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of chain extenders 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 Glycols such as glycol can be mentioned. Moreover, as a chain extender having two amino groups, for example, aromatic diamines such as tolylenediamine, xylylenediamine, diphenylmethanediamine, etc., 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 decanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropyritin cyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, 1 , 3-Bisaminomethylcyclohexane Alicyclic diamines, and the like of.

  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 emulsifying type using an emulsifying agent, a self-emulsifying type or a water-soluble type using a hydrophilic group in the urethane resin, and the like. In particular, a self-emulsification type in which ion groups are introduced into the structure of the urethane resin to form an ionomer is preferable because it is excellent in the storage stability of the liquid and the water resistance, transparency and adhesion of the obtained coated layer.

Moreover, as an ionic group to introduce | transduce, although various things, such as a carboxyl group, a sulfonic acid, phosphoric acid, a phosphonic acid, a quaternary ammonium salt, are mentioned, a carboxyl group is preferable. As a method of introducing a carboxyl group into the urethane resin, various methods can be taken in each step of the polymerization reaction. For example, there is a method of using a resin having a carboxyl group as a copolymerization component, or a method of using a component having a carboxyl group as one component such as a polyol, a polyisocyanate, or a chain extender at the time of prepolymer synthesis. In particular, it is preferable to use a carboxyl group-containing diol and introduce a desired amount of carboxyl group depending on the amount of this component charged.
For example, copolymerizing dimethylol propionic acid, dimethylol butanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid, etc. with a diol used for polymerization of urethane resin Can. The carboxyl group is preferably in the form of a salt neutralized with ammonia, an amine, an alkali metal, an 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 is 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, the solvent resistance, the water resistance, the blocking resistance and the like of the coating layer obtained while being excellent in the stability in the liquid state before coating.

  In addition, in forming the coating layer, use a crosslinking agent in combination in order to strengthen the coating film of the coating layer and improve sufficient adhesion with the anti-sticking layer, the hard coat layer, the light diffusion layer, etc. Is preferred.

  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 etc. are mentioned. In addition, in order to further improve the adhesion to the functional layer, it is possible to use two or more cross-linking agents in combination. Among the above, oxazoline compounds, epoxy compounds, isocyanate compounds and carbodiimide compounds are more preferable from the viewpoint of good adhesion, and in particular, oxazoline compounds and epoxy compounds, oxazoline compounds and isocyanate compounds, oxazoline compounds and carbodiimide compounds It has been found that adhesion is significantly improved when used in combination. In addition, from the viewpoint of increasing the strength of the coated layer, melamine compounds are more preferable.

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

  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, still more preferably 4 to 6 mmol in terms of oxazoline group content. It is in the range of / g. Use in the above range is preferable because adhesion to various functional layers is improved.

  The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensation products of epichlorohydrin and a hydroxyl group or amino group such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A, etc. There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidyl amine compounds and the like. Examples of polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane Examples of polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, Examples of tetramethylene glycol diglycidyl ether and monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and as a glycidyl amine compound, N, N, N ′, N′-tetraglycidyl-m-xylyl. And diamines, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

  An isocyanate type compound is a compound which has an isocyanate derivative structure represented by isocyanate or block isocyanate. As an isocyanate, for example, aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethyl xylylene diisocyanate Aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, aliphatic isocyanate such as hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyldiisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones and carbodiimide-modified products of these isocyanates can also be mentioned. These may be used alone or in combination of two or more. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet light.

  When used in the form of blocked isocyanate, examples of the blocking agent include bisulfite, phenol, phenolic compounds such as cresol and ethylphenol, propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, alcohol such as methanol and ethanol Compounds, active malne compounds such as dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, and lactam compounds such as ε-caprolactam and δ-valerolactam , Amine compounds such as diphenylaniline, aniline and ethyleneimine, acetanilide, acid amide compound of acetic acid amide, formaldehyde, acetoaldo Oxime compounds such as oxime, acetone oxime, methyl ethyl ketone oxime and cyclohexanone oxime may be mentioned, 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 to the functional layer is easily improved.

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

  A carbodiimide type compound is a compound which has a carbodiimide structure, and is used for the improvement of adhesiveness with various surface functional layers which may be formed on a coating layer, and the improvement of the moist heat resistance of a coating layer. is there. The carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule, but a polycarbodiimide compound having two or more in the molecule is more preferable for better adhesion and the like.

  The carbodiimide type 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, hexadiisocyanate can be used. Methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, dicyclohexylmethane diisocyanate and the like can be mentioned.

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

  The content of the carbodiimide group contained in the carbodiimide compound is usually 100 to 1000, preferably 250 to 800, more preferably 300 in terms of carbodiimide equivalent (weight [g] of the carbodiimide compound to give 1 mol of carbodiimide group). It is preferably in the range of -700, more preferably 350-650. Use in the above range is preferable because adhesion to various functional layers is improved.

  The melamine compound is a compound having a melamine skeleton in the compound and, for example, an alkylolated melamine derivative, a compound obtained by reacting an alcohol with an alkylolated melamine derivative to partially or completely etherify, and a compound thereof Mixtures can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol etc. are used suitably. Moreover, as a melamine compound, any of a monomer or the multimer more than a dimer may be sufficient, or you may use these mixtures. Furthermore, a product obtained by co-condensing urea or the like with part of melamine can also be used, and a catalyst can also be used to increase the reactivity of the melamine compound.

  In addition, these crosslinking agents are used by the design which is made to react in a drying process and a film forming process, and to improve the performance of a coating layer. It can be inferred that unreacted components of these crosslinkers, compounds after reaction, or a mixture thereof are present in the finished coating layer.

  Furthermore, in the range which does not impair the main point of the present invention, an antifoamer, a coatability improvement agent, a thickener, an organic system lubricant, an antistatic agent, an ultraviolet absorber, an antioxidant as needed for formation of a coating layer It is also possible to use a foaming agent, a dye, a pigment and the like in combination.

  As a ratio in the coating layer which comprises the laminated polyester film in this invention, an acrylic resin is 20 to 90 weight% normally, Preferably it is 30 to 85 weight%, More preferably, it is the range of 40 to 75 weight%. By using in the said range, it is effective in favorable adhesiveness and fall-off prevention of particle | grains.

  The proportion of the particles in the coated layer of the laminated polyester film of the present invention is usually 3 to 70% by weight, preferably 10 to 60% by weight, more preferably 15 to 50% by weight, still more preferably 20 to 40%. It is in the range of%. By using in the said range, adjustment of an effective haze is attained.

  The proportion of the component derived from the crosslinking agent is usually 80% by weight or less, preferably in the range of 5 to 60% by weight, and more preferably in the range of 10 to 45% by weight as a proportion in the coated layer constituting the laminated polyester film in the present invention. is there. By using in the said range, it becomes a favorable application | coating external appearance and a firm application layer.

  In the polyester film of the present invention, it is also possible to provide a coating layer on the surface opposite to the surface provided with the coating layer described above. For example, in the case where a functional layer such as a prism layer or a microlens layer is formed on the opposite side of the anti-sticking layer, the hard coat layer, and the light diffusion layer, adhesion with the functional layer can be improved. . As the components of the coating layer formed on the opposite surface, conventionally known ones can be used. For example, polymers such as polyester resin, acrylic resin and urethane resin, oxazoline compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, crosslinking agents such as carbodiimide compounds, melamine compounds and the like may be mentioned, and these materials may be used alone. A plurality of types may be used in combination.

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

  With respect to the formation of the coating layer, a series of compounds described above are used as a solution or a dispersion of a solvent, and a coating solution having a solid content concentration adjusted to about 0.1 to 80% by weight is coated on a 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 aqueous dispersion is more preferable, but a small amount of organic solvent is added to the coating solution for the purpose of improving dispersibility in water, film forming property, etc. You may contain. The organic solvent may be used alone or in combination of two or more.

  With regard to the laminated polyester film in the present invention, the thickness of the coating layer provided on the polyester film is in the range of 0.03 to 1 μm, preferably 0.03 to 0.5 μm, more preferably 0.03 to 0.2 μm. is there. When the film thickness is out of the above range, the coating appearance may be deteriorated or the adhesion to the functional layer may be deteriorated. Further, in applications requiring high total light transmittance, it is preferable to consider more precise film thickness adjustment, and the range is preferably 0.04 to 0.2 μm, more preferably 0. The thickness is preferably in the range of 0.16 to 0.17 μm, more preferably in the range of 0.08 to 0.14 μm.

  Further, in the case of a method of forming surface irregularities in the coating layer using particles, the relationship between the average particle diameter of the particles and the thickness of the coating layer is preferably 1.0 as the average particle diameter / thickness of the coating layer. The above range is more preferable, the range of 1.2 to 20 is more preferable, the range of 1.5 to 15 is more preferable, and the range of 1.7 to 10 is particularly preferable. By using in the said range, high haze can be carried out as a lamination | stacking polyester film which provided the application layer, and the haze reduction after providing a functional layer can be performed effectively. Further, it also contributes to preventing the particles from falling off the coated layer.

  In the film of the present invention, as the method for forming the coating layer, for example, gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze Conventional known coating methods such as coating, impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating 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, in the case of providing the coating layer by off-line coating, usually 3 to 40 at 80 to 200 ° C. The heat treatment is preferably performed for 2 seconds, preferably at 100 to 180 ° C. for 3 to 40 seconds.

  On the other hand, when providing a coating layer by in-line coating, it is good to heat-process generally for 3 to 200 second as a standard at 70-270 degreeC.

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

It is essential that the reduction of haze by forming a functional layer on the coated layer of the polyester film of the present invention is 1.0% or more, preferably 3.0% or more, more preferably 5.0% The range is more preferably 8.0% or more, particularly preferably 10% or more.
By setting the above range, it becomes easy to distinguish between processed and unprocessed functional layers from various viewpoints such as a conference room, a work room, an inspection room, and a film.

  Although the haze of the polyester film of the present invention is not particularly limited, it is preferably 2.0% or more. When adjusting the haze with particles, the appearance of the film depends on the type and size of the particles used, but it can not be said indiscriminately, but in order to make it easier to distinguish between processed and unprocessed functional layers. Is preferably more than 5.0%, more preferably more than 8.0%, still more preferably more than 10%, particularly preferably more than 12%. As a result of examination, it was found that within the scope of the present invention, even with the same haze value, the smaller the average particle size of the particles, the more white the apparent haze value, and the distinction between processed and unprocessed functional layer Found that it is easier to put on.

  The total light transmittance of the laminated polyester film is also affected by the state of the polyester film surface (the presence or absence of a coated layer and the type of coated layer) on the opposite side to the coated layer containing the acrylic resin of the present invention. Although it can not be argued, it is preferably 90.0% or more, more preferably 90.5% or more, and still more preferably 91.0% or more, particularly in applications where the total light transmittance is desired to be high.

  In order to more accurately grasp the optical characteristics of only the coating layer containing the acrylic resin of the present invention, it is good to consider the absolute reflectance of only the coating layer. The reflectance and the transmittance are mutually related characteristics, and in a polyester film with low light absorption, it is generally noted that a high transmittance indicates a low reflectance.

  In particular, in applications where it is desired to increase the total light transmittance, in order to increase the total light transmittance, the coated layer must have a minimum absolute reflectance of less than 3.5% in the wavelength range of 400 to 800 nm. It is preferably in the range of preferably 3.0% or less, more preferably 2.5% or less, and particularly preferably 2.0% or less.

  It is general to form a functional layer on the coated layer of the laminated polyester film of the present invention. The functional layer is, for example, a layer provided to impart various functions such as an anti-sticking layer, a hard coat layer, a light diffusion layer, a prism layer, a microlens layer, an ink layer, an adhesive layer, and an adhesive layer. It is. Among these functional layers, in the present invention, it is particularly suitable for the anti-sticking layer, the hard coat layer, and the light diffusion layer having a low haze. The functional layer is not particularly limited as long as the haze is lowered when formed on the coating layer, but usually the haze is preferably not very high, and the haze of the functional layer alone is preferably 8.0% or less, It is more preferably in the range of 3.0% or less, still more preferably 1.0% or less, and particularly preferably 0.5% or less. The thickness of the functional layer is not particularly limited as long as the haze is lowered when formed on the coating layer, but is preferably 0.1 to 50 μm, more preferably 1 to 15 μm, and still more preferably 1 to 5 μm. It is in the range of 10 μm.

  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 the purpose of light diffusion, so the method of containing smaller amount with smaller particle size is general It is.

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

  The binder to be contained in the anti-sticking layer and the light diffusion layer is used to fix the particles, and, for example, polyester resin, acrylic resin, polyurethane resin, fluorine resin, silicone resin, epoxy resin, ultraviolet curable resin, etc. Can be mentioned. In view of processability, a polyol compound is suitably used, and examples thereof include acrylic polyol and polyester polyol.

  When a polyol compound is used as a binder, it is preferable to include an isocyanate as a curing agent. By containing an isocyanate, a stronger crosslinked structure can be formed, and the physical properties of the functional layer are improved. Moreover, when using an ultraviolet curable resin as a binder, acrylate resin is preferable and it can be used for the improvement of the hardness of a functional layer.

  The sticking prevention layer and the light diffusion layer may contain, if necessary, 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. The range is more preferably in the range of 0.5 to 20.

  Examples of the method for forming the anti-sticking layer and the light diffusion layer include a method of preparing a coating solution containing a binder and particles, and applying and drying it. As a coating method, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating, spray coating and spin coating can be used. The thickness of the sticking prevention layer or the light diffusion layer is not particularly limited, but is preferably 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.

  In the case of the hard coat layer as an example of the functional layer, the material to be used is not particularly limited, but, for example, reactive silicon compounds such as monofunctional (meth) acrylates, polyfunctional (meth) acrylates, tetraethoxysilane, etc. The cured product of Among these, from the viewpoint of coexistence of productivity and hardness, it is particularly preferable to be a polymerization cured product of a composition containing an active energy ray curable (meth) acrylate.

  The composition containing the active energy ray-curable (meth) acrylate is not particularly limited. For example, a mixture of one or more kinds of known active energy ray curable monofunctional (meth) acrylates, difunctional (meth) acrylates and polyfunctional (meth) acrylates, commercially available as a resin material for active energy ray curable hard coats In addition to the above, or those other than these, those to which other components are further added can 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 ) Alkyl (meth) acrylates such as acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc. Hydroxy Alkyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate and the like Aromatic (meth) acrylates such as xylalkyl (meth) acrylates, benzyl (meth) acrylates, phenoxyethyl (meth) acrylates, amino group-containing (meth) acrylates such as diaminoethyl (meth) acrylates, diethylaminoethyl (meth) acrylates, Ethylene oxide modified (meth) acrylates such as methoxyethylene glycol (meth) acrylate, phenoxy polyethylene gryl (meth) acrylate, phenylphenol ethylene oxide modified (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (Meth) acrylic acid etc. may be mentioned.

  The active energy ray-curable bifunctional (meth) acrylate is not particularly limited. For example, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6- Alkanediol di (meth) acrylates such as hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate Bisphenol-modified di (meth) acrylate such as bisphenol F ethylene oxide-modified di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, urethane di (meth) acrylate G, epoxy di (meth) acrylate and the like.

  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. Isocyanuric acid modified tri (meth), such as pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ε-caprolactone modified tris (acroxyethyl) isocyanurate Acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate isocyanate Down prepolymers, urethane acrylates such as dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, and the like.

  The other components contained in the composition containing the active energy ray-curable (meth) acrylate are not particularly limited. For example, inorganic or organic fine particles, a polymerization initiator, a polymerization inhibitor, an antioxidant, an antistatic agent, a dispersant, a surfactant, a light stabilizer, a leveling agent and the like can be mentioned. Moreover, when making it dry after film-forming in a wet-coating method, the solvent of arbitrary amounts can be added.

  As a method of forming the hard coat layer, when an organic material is used, a general wet coat method such as a roll coat method or a die coat method is adopted. The hard coat layer thus formed can be subjected to curing reaction by heating or irradiation with active energy rays such as ultraviolet rays or electron beams as required.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Method of measuring the intrinsic viscosity of polyester Weigh precisely 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed, and add 100 ml of mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) Dissolved and measured at 30.degree.

(2) Measuring Method of Average Particle Size The coated layer was observed using TEM (H-7650 manufactured by Hitachi High-Technologies Corporation, accelerating voltage 100 V), and the average value of the particle size of 10 particles was taken as the average particle size. .

(3) Method of Measuring Film Thickness of Coating Layer The surface of the coating layer was stained with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method was stained with RuO ₄ and the coated layer cross section was measured using TEM (H-7650, manufactured by Hitachi High-Technologies Corporation, acceleration voltage 100 V). In addition, the film thickness was measured in the location which does not contain the part of particle | grains.

(4) Measuring method of haze It measured according to JIS K 7136 using haze meter HM-150 made by Murakami Color Research Laboratory.

(5) Method of measuring the amount of decrease in haze when forming a functional layer As a functional layer, resin (Hallus hybrid UV-G301 manufactured by Nippon Shokuhin Co., Ltd.) 100 parts by mass, isocyanate (made by Sumika Bayer Urethane, Desmodur N-3200) 10 parts by mass, 3 parts by mass of acrylic resin particles having an average particle diameter 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 A film having an anti-sticking layer (the haze of the layer is 0.4%) was obtained. The haze was measured by the method according to (4), and the difference from the haze of the laminated polyester film before forming the functional layer was calculated.

(6) Measurement Method of Total Light Transmittance Measured according to JIS K 7361 using a haze meter HM-150 manufactured by Murakami Color Research Laboratory.

(7) Evaluation method of absolute reflectance from the coated layer surface in polyester film In order to measure the absolute reflectance on one side of polyester film, black tape is previously measured on the back surface of polyester film for the purpose of suppressing reflection from the back surface. (Vinyl tape VT-50 manufactured by Nichiban Co., Ltd.), synchronous mode, incidence using a spectrophotometer (UV-visible spectrophotometer V-570 manufactured by JASCO and automatic absolute reflectance measuring device ARM-500N) Measure the absolute reflectance of the coated layer surface in the wavelength range of 400 to 800 nm at an angle of 5 °, N polarized light, response fast, data storage interval of 1.0 nm, bandwidth of 10 nm, and scanning speed of 1000 m / min. Was evaluated.

(8) Discrimination evaluation method before and behind functional layer processing The difference of 20 cm x 20 cm films before and after forming a functional layer of said (5) was observed. As a method of observation, assuming a conference room, a work room, and an examination room, a film and a functional layer are formed in which a functional layer is not formed in three places on white desk, on a mat for green cutter, and on black desk. The film was placed, and the difference between the two when observed from a position 1 m away from right above and 30 degrees diagonally was confirmed. If the difference can be determined instantly by 5 points, if it can be easily determined by observation for 3 seconds 4 points, if you look closely and 3 points if it can be determined, 2 cases if it is difficult to determine, 1 point if it can not be determined did. The higher the score, the better. It is ideal that there are three or more points when observed from directly above or obliquely under any of the three conditions.

(9) Evaluation method of adhesion of coating layer The film on which the functional layer of the above (5) is formed is cross-cut by 10 × 10, and an 18 mm wide tape (Sellotape made by Nichiban Co., Ltd.) (Registered trademark) CT-18) was attached and peeled off rapidly at a peeling angle of 180 degrees. The peeled surface was observed, and if the peeled area was less than 10%, it was rated as ○, if 10% or more and less than 30%, it was rated as Δ, and if it exceeded 30%, it was rated as x.

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

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

<Method of producing polyester (C)>
A polyester (C) is obtained using the same method as the polyester (A) production method except that 0.3 parts by weight of silica particles having an average particle diameter of 2 μm is added before the melt polymerization in the production method of the polyester (A). The

Examples of compounds constituting the coating layer are as follows.
(Example of compound)
Acrylic resin: (IA) aqueous dispersion of acrylic resin polymerized according to the following composition: ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) Emulsion polymers (emulsifier: anionic surfactant)

Acrylic resin: (IB) Water dispersion of acrylic resin polymerized according to the following composition: ethyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / N-methylol acrylamide / acrylic acid = 65/28/3/2/2 (% by weight ) Emulsion polymers (emulsifier: anionic surfactant)

・ Polyester resin: (IC)
Aqueous 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%)

-Urethane resin: (ID)
Isophorone diisocyanate unit: terephthalic acid unit: isophthalic acid unit: ethylene glycol unit: diethylene glycol unit: dimethylol propanoic acid unit = 12: 19: 18: 21: 25: 5 (mol%) Water of polyester-based urethane resin Dispersion.

Particles: (IIA) Silica particles having an average particle size of 0.15 μm: (IIB) Silica particles having an average particle size of 0.20 μm: (IIC) Silica particles having an average particle size of 0.30 μm: (IID ) Silica particles with an average particle size of 0.45 μm

・ Oxazoline compound: (IIIA)
Acrylic polymer having oxazoline group and polyalkylene oxide chain EPOCROS (Oxazoline group weight = 4.5 mmol / g, Nippon Shokubai Co., Ltd.)

Epoxy compounds: (IIIB) polyglycerol polyglycidyl ether

・ Isocyanate compound: (IIIC)
1000 parts of hexamethylene diisocyanate were stirred at 60 ° C., and 0.1 part of tetramethylammonium capriate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction to obtain an isocyanurate type polyisocyanate composition. 100 parts of the obtained isocyanurate type polyisocyanate composition, 42.3 parts of methoxy polyethylene 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 temperature of the reaction solution was maintained at 60 ° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 parts of a 28% methanol solution of sodium methoxide were added, and held for 4 hours. Blocked polyisocyanate obtained by adding 58.9 parts of n-butanol and holding the reaction solution temperature at 80 ° C. for 2 hours and then adding 0.86 parts of 2-ethylhexyl acid phosphate.

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

Melamine compounds: (IIIE) hexamethoxymethylolmelamine

Example 1:
A mixed material in which polyesters (A), (B) and (C) are mixed at a ratio of 91%, 3% and 6%, respectively, is used as a material of the outermost layer (surface layer), and polyesters (A) and (B) are each 97 The mixed raw materials mixed at 1% and 3% ratio are used as the raw materials for the middle layer, and each is supplied to two extruders, melted at 285 ° C., and then cooled on a cooling roll set at 40 ° C. Coextrusion cooling and solidification were carried out with a layer configuration of layers (surface layer / intermediate layer / surface layer = 1: 18: 1 discharge amount) to obtain an unstretched sheet.
Then, after stretching the film in the longitudinal direction 3.4 times at a film temperature of 85 ° C. using the roll peripheral speed difference, the coating solution 1 shown in Table 1 below is coated on one side of this longitudinally stretched film and guided to a tenter, After stretching by 4.0 times at 120 ° C. in the lateral direction and heat treatment at 225 ° C., it is relaxed by 2% in the lateral direction, and the thickness of the coating layer (after drying) is 0.08 μm. A polyester film of 125 μm was obtained.

  When the obtained polyester film was evaluated, the haze was 4.2%, the haze reduction amount was 3.3%, and the discrimination between the film in which the functional layer was not formed and the film in which the functional layer was formed was good. Met. Also, the adhesion to the functional layer was good. The properties of this film are shown in Tables 2 and 3 below.

Examples 2 to 25:
A polyester film was obtained in the same manner as in Example 1 except that the coating composition was changed to the coating composition shown in Table 1 in Example 1. As shown in Tables 2 and 3, the polyester film thus formed had good discrimination between the film in which the functional layer was not formed and the film in which the functional layer was formed. Also, the adhesion to the functional layer was good.

Comparative Example 1:
A polyester film was obtained in the same manner as in Example 1 except that the coating layer was not provided in Example 1. When the finished polyester film was evaluated, as shown in Tables 2 and 3 below, it is a result that the discrimination between the film in which the functional layer is not formed and the film in which the functional layer is formed is inferior and the adhesion is poor. The

Comparative Examples 2 and 3:
A polyester film was obtained in the same manner as in Example 1 except that the coating composition was changed to the coating composition shown in Table 1 in Example 1. When the finished polyester film was evaluated, as shown in the following Tables 2 and 3, the discriminability of the film in which the functional layer was not formed and the film in which the functional layer was formed was not sufficient.

  The film of the present invention is intended to make it easy to distinguish between processed and unprocessed functional layers, for example, in applications such as backlight units for liquid crystal displays, functional layers such as sticking prevention layers, hard coat layers and light diffusion layers, etc. It can be suitably used for applications.

Claims (13)

A polyester film having a coating layer containing particles on at least one side thereof for providing a functional layer on the coating layer and having a haze of 1.0% or more when the functional layer is formed on the coating layer decreased, the average particle diameter of said particles is in the range of 0.01 to 1.0 [mu] m, laminated polyester film thickness of the coating layer has a range der Rukoto of 0.03 to 1 [mu] m. The laminated polyester film according to claim 1, wherein the haze of the functional layer is 8.0% or less. The laminated polyester film according to claim 1 , wherein the particles are inorganic particles . The laminated polyester film according to any one of claims 1 to 3, wherein the relationship between the average particle diameter of the particles and the film thickness of the coating layer is 1.0 or more as an average particle diameter / film thickness of the coating layer . The laminated polyester film according to any one of claims 1 to 4, wherein the coated layer contains a crosslinking agent . The laminated polyester film according to any one of claims 1 to 5, wherein the coated layer has a minimum absolute reflectance of less than 3.5% in a wavelength range of 400 to 800 nm . The laminated polyester film according to any one of claims 1 to 6, wherein the haze is 2.0% or more . The total light transmittance is 90.0% or more, The laminated polyester film in any one of Claims 1-7 . The functional layer is a layer selected from an antisticking layer, a hard coat layer, a light diffusion layer, a prism layer, a microlens layer, an ink layer, an adhesive layer, and an adhesive layer. Laminated polyester film. The laminated polyester film according to claim 9, wherein the functional layer comprises an active energy ray curable composition . The member for liquid crystal displays which formed the functional layer on the laminated polyester film in any one of Claims 1-10. A coated layer containing particles is formed on at least one side of the polyester film, the average particle diameter of the particles is in the range of 0.01 to 1.0 μm, and the film thickness of the coated layer is in the range of 0.03 to 1 μm, A determination method for determining whether or not a functional layer has been processed or not by lowering the haze by 1.0% or more when the functional layer is formed on the coated layer. A method for producing a polyester film having a coating layer containing particles on at least one side and providing a functional layer on the coating layer, wherein the step of forming the coating layer by in-line coating on at least one side of the polyester film is disclosed. When the functional layer is formed on the coating layer, the haze decreases by 1.0% or more, the average particle diameter of the particles is in the range of 0.01 to 1.0 μm, and the film thickness of the coating layer Is in the range of 0.03 to 1 .mu.m.