Easy-adhesion polyester film

Abstract

The purpose of the present invention is to provide an easy-adhesion polyester film capable of suppressing occurrence of nonuniformity caused by a coating layer (easy-adhesion layer) and maintaining the adhesiveness, and further capable of suppressing adverse effects on the ecosystem for the future.　The present invention pertains to an easy-adhesion polyester film which includes a polyester film as a base film and has an easy-adhesion layer on at least one surface of the base film. The easy-adhesion layer is formed by curing a composition containing a polyester resin (A), a urethane resin (B), a crosslinking agent (C), a solvent (D), and a silicone-based compound (E). The silicone-based compound (E) has a mass average molecular weight of 350-1500. The content of the silicone-based compound (E) in the composition is 0.01-2.00 mass% with respect to 100 parts by mass of the total solid content of the polyester resin (A) and the urethane resin (B) contained in the composition. The content of a fluorine-based compound in the solid content of the composition is 100 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and the urethane resin (B) contained in the composition.

Description

Easy-to-adhere polyester film

[0001] This invention relates to an easily adhesive polyester film.

[0002] In recent years, displays in devices such as LCD televisions, laptop computers, tablet devices, and mobile phone terminals have been increasing in resolution. As resolution increases, the area of ​​the black matrix region increases, which reduces the aperture ratio at each pixel, making brightness adjustment of the backlight unit crucial. Methods to improve the optical efficiency of the backlight unit include backlights in which a lens sheet, such as a lens sheet with many prism rows or a lenticular row of lens units formed on one side, is provided on the light-emitting surface side of the backlight's light guide.

[0003] These lens sheets improve frontal brightness by refracting the light emitted from the backlight and directing it towards the front of the display. Typically, lens sheets use transparent plastic resins such as polycarbonate, acrylic, or polyester as the base film due to their excellent moldability. Among these, polyester film is widely used due to its superior transparency, dimensional stability, and chemical resistance.

[0004] Such polyester films used as substrates are provided with an easy-adhesion layer to facilitate adhesion to other layers (for example, a hard coat layer for protecting the display). The easy-adhesion layer is formed by applying and drying a resin composition for forming the easy-adhesion layer to one or both sides of the substrate film (for example, Patent Documents 1 and 2).

[0005] International Publication No. 2020 / 158403, Japanese Patent Publication No. 2013-253189

[0006] Regarding coatings applied to films, fluorine-based additives are frequently used to impart wettability of the coating solution to the film, as well as liquid leveling properties during drying after coating. Fluorine-based additives have been favored as surfactants due to their extremely high surface tension-reducing effect. On the other hand, the configuration of components such as the light source of LCD televisions is changing, and there are cases where optical designs different from conventional products are required. For example, when a coated film is used as an easily adhesive film for optical systems such as polarizer protective plates in LCD televisions, it is desirable to further suppress the occurrence of unevenness caused by the coating layer (easily adhesive layer).

[0007] Furthermore, in recent years, there has been a growing demand for environmentally conscious product manufacturing in industrial products such as televisions. For example, while the amount of fluorine-based surfactants contained in an easy-to-adhere polyester film is small when considered as a single product, if the amount released into the environment increases, even trace amounts of this component can no longer be ignored. For instance, the European Environmental Control Agency (ECHA) is concerned about the environmental persistence, bioaccumulation, and health effects of perfluorinated compounds (PFAS), and is considering regulations. Under ECHA's definition, it is expected that most fluorine-based surfactants will fall under the category of regulated substances in the future. Therefore, even if regulations are not currently in place, considering the future impact on ecosystems, etc., a reduction in fluorine-based surfactants is necessary. Thus, in recent years, the environmental release of fluorine compounds has become a growing concern. In addition, with the increasing resolution of displays, unevenness in the easy-to-adhere layer can negatively affect the optical properties of the polyester film, leading to stricter requirements for the easy-to-adhere layer.

[0008] However, there are reasons why fluorinated surfactants cannot be simply replaced with other compounds. For example, when an easily adhesive polyester film is used in optical applications, it must meet the required optical properties. If the wettability of the coating solution or the liquid leveling properties during drying after coating changes, the properties of the resulting easily adhesive polyester film may change, such as the occurrence of unevenness in the optical properties. Also, if the resin design is based on a fluorinated surfactant, simply replacing the fluorinated surfactant with another surfactant may reduce the adhesion between the base film and the easily adhesive layer. For these reasons, there is a need for an easily adhesive polyester film that can suppress the occurrence of unevenness caused by the coating layer (easily adhesive layer), maintain adhesion, and further minimize adverse impacts on ecosystems in the future.

[0009] As a result of diligent research, the inventors of the present invention have discovered a polyester film having an easily adhesive layer with a low content of fluorine-based compounds, suppressed unevenness, high smoothness, and excellent adhesion to functional layers such as hard coat layers, thereby completing the present invention.

[0010] The present invention includes, for example, the following embodiments. Item 1. An easily adhesive polyester film having a polyester film as a base film and an easily adhesive layer on at least one surface of the base film, wherein the easily adhesive layer is formed by curing a composition containing a polyester resin (A), a urethane resin (B), a crosslinking agent (C), a solvent (D), and a silicone compound (E), wherein the mass average molecular weight of the silicone compound (E) is 350 or more and 1500 or less, the content of the silicone compound (E) in the composition is 0.01% by mass or more and 2.00% by mass or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition, and the content of the fluorine compound in the solid content of the composition is 100 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition. Item 2. The easy-to-adhere polyester film according to item 1, wherein the silicone compound (E) has a mass-average molecular weight of 350 or more and 1250 or less, the content of the silicone compound (E) in the composition is 0.05% by mass or more and 1.50% by mass or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition, and the content of the fluorine compound in the solid content of the composition is 75 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition. Item 3. The easy-to-adhere polyester film according to item 1 or 2, wherein the silicone compound (E) has the property that the haze of the solution obtained by dissolving the silicone compound (E) in water at a concentration of 5% by mass is 0% or more and 5% or less. Item 4. An easy-to-adhere polyester film according to any one of items 1 to 3, wherein the amount of fluorine obtained by immersing the easy-to-adhere polyester film in 500 ml of ultrapure water at 25°C for 24 hours and then analyzing it with EPA method 1621 is 5.0 μg-F / L or less. Item 5. An easy-to-adhere polyester film according to any one of items 1 to 4, wherein the silicone compound (E) has the structure shown by the following structural formula (II). [In the formula, R ２ R is a hydrogen or methyl group.３ is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is 2 to 4, n is 0 to 28, X is 0 to 1.5, and Y is 0.5 to 1.5. Item 6. The easy-to-adhere polyester film is an environmentally friendly easy-to-adhere polyester film for optical use, as described in any one of items 1 to 5.

[0011] The present invention provides a polyester film having an easily adhesive layer with a low fluorine-based compound content, suppressed unevenness, high smoothness, and excellent adhesion to functional layers such as hard coat layers. The easily adhesive polyester film of the present invention has excellent aesthetics and high visual quality due to its suppression of unevenness and high smoothness, and is particularly suitable as an optical film. Furthermore, the easily adhesive polyester film of the present invention has excellent adhesion to the base film and to functional layers or functional films that can be laminated in subsequent processes. In addition, because the easily adhesive polyester film of the present invention does not use fluorine-based surfactants, adverse effects on the environment and human health are significantly reduced, making it useful as an environmentally friendly easily adhesive polyester film for optical applications.

[0012] In this specification, the phrase "contains" is used to include the phrases "essentially consist of" and "consist of".

[0013] In the numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in a given step may be arbitrarily combined with the upper or lower limit of a numerical range in that paragraph or in another step. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with a value shown in the example or a value that can be uniquely derived from the example.

[0014] In this specification, numbers enclosed in "~" signify a numerical range that includes the numbers before and after "~" as the lower and upper limits, respectively. For example, "1 to 10 mass%" is synonymous with "1 mass% or more and 10 mass% or less." Furthermore, regarding numerical ranges, "greater than or equal to" means "the same as or greater than," and "less than or equal to" means "the same as or less than."

[0015] In this specification, "environmentally friendly type" means not containing or substantially not containing fluorine-based additives. For example, an easy-adhesive polyester film in which the content of fluorine-based compounds is 75 ppm or less with respect to a total of 100 parts by mass of the solid content of the polyester resin (A) and the urethane resin (B) contained in the solid content of the composition for forming an easy-adhesive layer is an environmentally friendly type easy-adhesive polyester film.

[0016] (Base film) The easy-adhesive polyester film in the present invention can use a polyester film as the base film. Examples of the polyester resin constituting the polyester film as the base film include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4'-dicarboxylate, polyethylene-2,6-naphthalate, or a copolymerized polyester in which these resin constituent units are the main constituent units (constituent units occupying 50 mol% or more of the total constituent units of the polymer) and these constituent units are copolymerized with other arbitrary ester constituent units can be used.

[0017] The base film may contain particles. The types of particles can be, for example, organic particles such as siloxane copolymer acrylic resin, crosslinked polystyrene, polystyrene-divinylbenzene, polymethyl methacrylate, methyl methacrylate copolymer, methyl methacrylate copolymer crosslinked body, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguanamine resin, silicone resin, acrylic resin, etc., or inorganic particles such as silica, alumina, titanium dioxide, zirconium dioxide, kaolin, talc, graphite, calcium carbonate, feldspar, molybdenum disulfide, carbon black, barium sulfate, etc. The particles can be core-shell type particles having a multilayer structure composed of substances with different internal and external properties. Due to various preferable characteristics as a lubricant, silica particles are preferably used as the particles.

[0018] The content of the particles relative to the mass of the base film can be 1% by mass or less, preferably 0.2% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0.05% by mass or less. The lower limit of the content of the particles can be 0.001% by mass or more, preferably 0.005% by mass or more. The content of the particles can be 0.001% by mass or more and 1% by mass or less, 0.001% by mass or more and 0.2% by mass or less, 0.001% by mass or more and 0.1% by mass or less, 0.001% by mass or more and 0.05% by mass or less, 0.005% by mass or more and 1% by mass or less, 0.005% by mass or more and 0.2% by mass or less, 0.005% by mass or more and 0.1% by mass or less, 0.005% by mass or more and 0.05% by mass or less, etc. When the content of the particles is within the above range, it is advantageous in terms of suppressing the occurrence of scratch defects on the rolls during stretching and / or drying in the film-forming process and being able to adjust the haze to a low level and achieve good transparency.

[0019] The average particle diameter of the particles contained in the base film can be 0.1 μm or more and 2 μm or less, preferably 0.1 μm or more and 1.5 μm or less, and more preferably 0.1 μm or more and 1.0 μm or less. When the average particle diameter of the particles is within the above range, it is advantageous in terms of suppressing the occurrence of scratch defects on the rolls during stretching and / or drying in the film-forming process and being able to adjust the haze to a low level and achieve good transparency.

[0020] The base film can be a uniaxially stretched film or a biaxially stretched film, but a biaxially stretched film is preferred due to its mechanical properties, etc. The stretching method can be simultaneous biaxial stretching, but the manufacturing process of a sequentially biaxially stretched film can be preferably used.

[0021] The easily adhering polyester film of the present invention preferably has a haze of 2% or less. A haze of 2% or less is preferable because it results in good optical properties and appearance when used in optical fields or when printed. More preferably, it is 1.5% or less, and even more preferably 1.0% or less. While a smaller haze is preferable, it may be 0.1% or more, or 0.3% or more. The haze may be 0.1% to 2%, 0.1% to 1.5%, 0.1% to 1.0%, 0.3% to 2%, 0.3% to 1.5%, 0.3% to 1.0%, etc. The haze of the film can be measured in accordance with JIS K7136:2000 using a turbidimeter (Nippon Denshoku, NDH2000).

[0022] (Easy-Adhesion Layer) An easy-adhesion polyester film may have an easy-adhesion layer on one or both surfaces of the base film. The presence of an easy-adhesion layer on the base film improves the adhesion between the base film and inks, hard coat layers, etc. The easy-adhesion layer may be a layer formed by curing a composition (which may also be referred to as "coating liquid" in this specification) containing polyester resin (A), urethane resin (B), crosslinking agent (C), solvent (D), and silicone compound (E). Since it is extremely difficult to accurately describe the composition of the easy-adhesion layer after curing, the present invention uses the expression "formed by curing a composition containing polyester resin (A), urethane resin (B), crosslinking agent (C), solvent (D), and silicone compound (E)."

[0023] (Polyester resin (A)) The polyester resin constituting the easy-adhesion layer in the present invention may be linear, branched, or copolymerized polyester resin. Preferably, polyester resin (A) is a polyester resin composed of a dicarboxylic acid component and a glycol component (diol component). The polyester resin may also be a copolymerized polyester resin.

[0024] Examples of glycol components constituting the polyester resin include ethylene glycol, 1,3-propane glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol, xylene glycol, and ethylene oxide adducts of bisphenol A. One of these may be used alone or in combination of two or more. Ethylene glycol, diethylene glycol, neopentyl glycol, and 1,6-hexanediol are preferred as glycol components, with ethylene glycol and diethylene glycol being more preferred.

[0025] Examples of dicarboxylic acid components constituting the polyester resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (e.g., 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, etc.), 4,4-diphenyldicarboxylic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, adipic acid, sebacic acid, azelaic acid, phenylindanedicarboxylic acid, dimer acid, and their dimethyl derivatives (e.g., 2,6-naphthalenedicarboxylic acid dimethyl, dimethyl terephthalate, etc.), and may be used individually or in combination of two or more. Preferred dicarboxylic acid components include aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, sebacic acid, adipic acid, and their dimethyl derivatives; more preferred are naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, and their dimethyl derivatives; and even more preferred are 2,6-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid dimethyl. By using aromatic dicarboxylic acids (particularly 2,6-naphthalenedicarboxylic acid) or their dimethyl derivatives as the dicarboxylic acid component, the refractive index of the polyester resin can be increased, thereby increasing the refractive index of the easily bonded layer. For this reason, easily bonded polyester films having an easily bonded layer in which aromatic dicarboxylic acids or their dimethyl derivatives are used as the dicarboxylic acid component are suitable for optical applications. The proportion of aromatic dicarboxylic acid components in the total dicarboxylic acid components constituting the polyester resin can be 55 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, or 100 mol%, while the proportion of other dicarboxylic acid components can be 30 mol% or less, 20 mol% or less, 10 mol% or less, or 0 mol%. In particular, when moisture and heat resistance and high refractive index are important, it is preferable to set the proportion of aromatic dicarboxylic acid components to 90 mol% or more, more preferably 95 mol% or more, and especially 100%.

[0026] Furthermore, along with these components, unsaturated polybasic acids such as maleic acid, fumaric acid, and itaconic acid, and hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-(β-hydroxyethoxy)benzoic acid can be used. The proportion of the unsaturated polybasic acid component and the hydroxycarboxylic acid component may be 10 mol% or less, preferably 5 mol% or less, of the dicarboxylic acid component.

[0027] In addition to the dicarboxylic acid components mentioned above, it is preferable to mix in a terephthalic acid component having a sulfonic acid group or an isophthalic acid component having a sulfonic acid group in an amount of 1 to 10 mol% relative to the total dicarboxylic acid components in order to impart water dispersibility to the composition for forming an easily adhesive layer. For example, 4-sulfoisophthalic acid, sulfoterephthalic acid, 5-sulfoisophthalic acid, 5-sodium sulfoisophthalic acid, dimethyl-5-sodium sulfoisophthalate, 4-sodium sulfonaphthalene-2,7-dicarboxylic acid, and 5-(4-sulfophenoxy)isophthalic acid can be preferably used.

[0028] The content of polyester resin (A) in the composition for forming an easy-adhesion layer is preferably 15% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 55% by mass or less, of the total solid components of the composition for forming an easy-adhesion layer.

[0029] (Urethane resin (B)) Urethane resin (B) contains at least a polyol component and a polyisocyanate component as constituent components, and further contains a chain extender as needed. The above urethane resin is a polymer compound in which these constituent components are copolymerized mainly by urethane bonds. Examples of urethane resins include polyether polyurethane resin, polyester polyurethane resin, polycarbonate polyurethane resin, and urethane resin containing blocked isocyanate groups, and can be used individually or in combination of two or more. A preferred urethane resin (B) is polycarbonate polyurethane resin (polyurethane resin having a polycarbonate skeleton).

[0030] The polyol component (e.g., diol component, triol component) of the urethane resin (B) can be any known polyol, such as polyether polyol, polyester polyol, or polycarbonate polyol, depending on the application. In one embodiment, the urethane resin (B) may be a polyurethane resin having a polycarbonate skeleton. The diol component of the polyurethane resin having a polycarbonate skeleton preferably contains an aliphatic polycarbonate polyol, which has excellent heat resistance and hydrolysis resistance. In the optical applications of the present invention, it is preferable to use an aliphatic polycarbonate polyol from the viewpoint of preventing yellowing. Furthermore, including a polycarbonate polyol as a component of the urethane resin is one of the preferred forms because it can give flexibility to the coating film (easy-adhesion layer). These components of the urethane resin can be identified by nuclear magnetic resonance analysis or the like.

[0031] Examples of aliphatic polycarbonate polyols include aliphatic polycarbonate diols and aliphatic polycarbonate triols, but aliphatic polycarbonate diols are preferably used. Examples of aliphatic polycarbonate diols that are components of the urethane resin of the present invention include aliphatic polycarbonate diols obtained by reacting one or more diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol with carbonates such as dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and phosgene (e.g., polyhexamethylene carbonate diol).

[0032] Polyurethane resins with a polycarbonate backbone have a 1460 cm³ derivative derived from aliphatic polycarbonate components, as measured by infrared spectroscopy.－１ Absorbance in the vicinity (A1460) and 1530 cm² derived from urethane components －１ The ratio of absorbance (A1530) in the vicinity (A1460 / A1530) is preferably 0.40 to 2.30. When the ratio (A1460 / A1530) is 0.40 or higher, it is preferable because the amount of rigid urethane component does not become excessive, stress relaxation of the coating layer does not decrease, and there is no risk of a decrease in moisture and heat resistance. Furthermore, when the ratio (A1460 / A1530) is 2.30 or lower, it is preferable because the amount of aliphatic component of flexible aliphatic polycarbonate does not become excessive, the solvent resistance of the coating layer is maintained, and there is no risk of a decrease in moisture and heat resistance.

[0033] In order to set the ratio (A1460 / A1530) in the range of 0.40 to 2.30, the number-average molecular weight of the aliphatic polycarbonate diol is preferably 1500 to 4000, and more preferably 2000 to 3000. If the number-average molecular weight of the aliphatic polycarbonate diol is small, the relative proportion of the aliphatic polycarbonate component constituting the urethane resin becomes small.

[0034] Examples of polyisocyanates that are components of the urethane resin in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatemethyl)cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, or polyisocyanates obtained by pre-adding these compounds, either individually or in combination, with trimethylolpropane or the like. The aforementioned polyisocyanates are preferable for optical applications where high transparency is required and there is no problem of yellowing. Furthermore, these polyisocyanates are preferable because the coating film does not become too rigid, stress due to shrinkage and swelling of photocurable resins can be relieved, and adhesion is maintained.

[0035] To impart water solubility or water dispersibility to urethane resin, sulfonic acid (salt) groups or carboxylic acid (salt) groups can be introduced (copolymerized) into the urethane molecular backbone. Since sulfonic acid (salt) groups are strongly acidic and their hygroscopic properties can make it difficult to maintain the moisture resistance of the coating film, it is preferable to introduce weakly acidic carboxylic acid (salt) groups. Nonionic groups such as polyoxyalkylene groups can also be introduced.

[0036] To introduce carboxylic acid (salt) groups into urethane resin, for example, a polyol compound having carboxylic acid groups, such as dimethylolpropionic acid or dimethylolbutanoic acid, is introduced as a copolymer component and neutralized with a salt-forming agent. Specific examples of salt-forming agents include ammonia, trialkylamines such as trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, and tri-n-butylamine, N-alkylmorpholines such as N-methylmorpholine and N-ethylmorpholine, and N-dialkylalkanolamines such as N-dimethylethanolamine and N-diethylethanolamine. These can be used individually or in combination of two or more.

[0037] When a polyol compound having a carboxylic acid (salt) group is used as a copolymer component to impart water solubility, the molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is preferably 3 to 60 mol%, and more preferably 5 to 40 mol%, when the total polyol component of the urethane resin is considered to be 100 mol%. A molar ratio of 3 mol% or more is preferable because it provides good water dispersibility. Furthermore, a molar ratio of 60 mol% or less is preferable because it maintains water resistance and heat and humidity resistance.

[0038] In the present invention, the glass transition temperature of the urethane resin is preferably less than 0°C, and more preferably less than -5°C. A glass transition temperature of less than 0°C is preferable because it is easier to obtain suitable flexibility from the viewpoint of stress relaxation of the coated layer.

[0039] The urethane resin containing blocked isocyanate groups may be a heat-reactive, water-soluble urethane in which the terminal isocyanate groups are sealed with hydrophilic groups (hereinafter referred to as "blocked").

[0040] Examples of isocyanate group blocking agents include bisulfites, phenols containing sulfone groups, alcohols, lactams, oximes, and activated methylene compounds. The blocked isocyanate groups can make the urethane prepolymer hydrophilic or water-soluble. During the drying or heat setting process in film manufacturing, when thermal energy is applied to the urethane resin containing the blocked isocyanate groups, the blocking agent detaches from the isocyanate groups. As a result, the urethane resin (B) can fix the mixed polyester resin (A) to its self-crosslinked network and react with the end groups of the polyester resin (A). The urethane resin containing blocked isocyanate groups during the preparation of the coating solution (composition for forming an easily adhesive layer) is hydrophilic and therefore has poor water resistance. However, once the thermal reaction is completed after coating, drying, and heat setting, the hydrophilic groups of the urethane resin (B), i.e., the blocking agent, detach, resulting in a coating film with good water resistance.

[0041] An example of a urethane resin (B) containing the blocked isocyanate group described above is Elastron®, a registered trademark product manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0042] The content of urethane resin (B) in the composition for forming an easy-adhesion layer is preferably 40% by mass or more and 85% by mass or less, and more preferably 45% by mass or more and 80% by mass or less, of the total solid components of the composition for forming an easy-adhesion layer.

[0043] The total solid content of polyester resin (A) and urethane resin (B) in the easy-adhesion layer forming composition is preferably 80% by mass or more and 98% by mass or less, and more preferably 85% by mass or more and 97.5% by mass or less, of the total solid components of the easy-adhesion layer forming composition.

[0044] (Crosslinking agent (C)) By including a crosslinking agent (C), adhesion under high temperature and high humidity conditions can be further improved. The crosslinking agent (C) is not particularly limited, but examples include urea compounds, melamine compounds, isocyanate compounds, oxazoline compounds, epoxy compounds, and carbodiimide compounds, and can be used individually or in combination of two or more. As the crosslinking agent (C), melamine compounds, isocyanate compounds, oxazoline compounds, and carbodiimide compounds are preferred due to their long-term stability of the composition for forming the easily adhesive layer and their effect on improving adhesion under high temperature and high humidity treatment. Catalysts and the like can be used as needed to promote the crosslinking reaction.

[0045] The crosslinking agent (C) content in the easy-adhesion layer forming composition is preferably 5% by mass or more and 50% by mass or less of the total solid components of the easy-adhesion layer forming composition. More preferably, it is 10% by mass or more and 40% by mass or less. If it is 10% by mass or more, the strength of the resin in the coated layer is maintained and adhesion under high temperature and high humidity conditions is good, and if it is 40% by mass or less, the flexibility of the resin in the coated layer is maintained and adhesion under room temperature and high temperature and high humidity conditions is good, which is preferable.

[0046] Examples of solvent (D) include water and mixed solvents of water and alcohol. Lower alcohols such as isopropyl alcohol are preferred. The mass ratio of water to alcohol in the mixed solvent is preferably selected within the range of 100 / 0 to 85 / 15, expressed as water / alcohol. It is preferable that the mass ratio of alcohol be 15 parts by mass or less relative to the total mass of water and alcohol, as this allows for easy production using a conventional biaxially oriented film manufacturing apparatus. When the mass ratio of water / alcohol is within the range of 98 / 2 to 90 / 10, it is desirable that the surface tension of the coating solution can be controlled by adding alcohol, making it easier to adjust the appearance of the easily adhesive layer.

[0047] The solvent (D) in the composition for forming an easily adhesive layer may be the remainder of the polyester resin (A), urethane resin (B), crosslinking agent (C), silicone compound (E), and any other components that may be optionally included. The content of solvent (D) is preferably 2% by mass or more and 35% by mass or less, and more preferably 4% by mass or more and 15% by mass or less, based on the mass of the composition.

[0048] (Silicone compound (E)) In the present invention, the easy-adhesion layer includes a silicone compound (E). The silicone compound can be selected within the scope of the present invention. Furthermore, in order to make the film surface smooth and highly transparent, the type and amount of silicone compound added can be appropriately selected within the scope of the present invention.

[0049] The inventors of this invention have conducted thorough research and have hypothesized that when a composition for forming an easily adhesive layer contains a fluorine-based surfactant, the interfacial tension of the fluorine-based surfactant has some influence on the occurrence of unevenness in the easily adhesive layer. For example, CF contained in the fluorine-based surfactant ３ - Structure and - CF ２ -CF ２ - The critical surface tensions of the structures are approximately 6 and 14 mN / m, respectively, and it is known that even a small amount can significantly reduce the surface tension of the entire coating solution. Furthermore, since the Rf group, which is the hydrophobic group of the fluorinated surfactant, also has oil-repellent properties, it is considered that it has little effect on reducing the interfacial tension between oil and water. On the other hand, the surface tension of polyester resin is said to be 45 mN / m (Kazuyuki Sugita, Journal of the Japan Society of Printing Science and Technology, 35, 4, pp. 202-210 (1998)). This suggests that the interfacial tension between the polyester resin, polyurethane resin, etc., contained in the easy-adhesion layer and the fluorine-based surfactant is large, and that the binder component and the fluorine-based surfactant do not mix easily. While this should not be interpreted in isolation from any particular theory, the inventors considered that in the process of drying the easy-adhesion layer-forming composition (coating liquid) after coating, the fluorine-based surfactant undergoes phase separation with the binder resin early in the process. As a result, when aiming for further improvement in quality, it is thought that unevenness in the coated surface due to phase separation may occur. The inventors diligently studied these findings and completed the present invention.

[0050] Although it should not be construed as being limited to a specific theory, the mass average molecular weight of the silicone-based compound (E) is 350 or more and 1500 or less, and the content of the silicone-based compound (E) in the composition of the present invention is 0.01% by mass or more and 2.00% by mass or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and the urethane resin (B) contained in the composition. The content of the fluorine-based compound in the solid content of the composition is 100 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and the urethane resin (B) contained in the composition. It is considered that phase separation between the binder resin and the silicone-based compound can be suppressed. In particular, the silicone-based compound according to the present invention can reduce the difference in surface tension (interfacial tension) with the polyester resin (A) and the urethane resin (B), which are binder components, with respect to the fluorine-based surfactant, and while expressing the effect of lowering the surface tension of the coating liquid, it is considered that unevenness on the coated surface can be suppressed. In addition, in the present invention, not only unevenness can be suppressed, but good adhesion to the substrate and good adhesion to the functional layer laminated or coated in the subsequent process can be shown. In the present invention, suppression of unevenness may be referred to as "suppression of iridescent color under a fluorescent lamp".

[0051] As the silicone-based compound (E), in order to suppress unevenness on the film surface and achieve high transparency, the type and addition amount can be appropriately selected within the scope of the present invention. As the silicone-based compound (E), silicone-based compounds manufactured by Shin-Etsu Silicone, Toray Dow Corning, and Momentive can be preferably used.

[0052] In one aspect, the silicone-based compound (E) is preferably a nonionic silicone-based compound that is not easily affected by pH changes, and particularly polyoxyalkylene-modified silicone can be used. Specifically, it is represented by the following average composition formula (I). R 1 xR 2 ySiO (4-x-y) / 2 (I) [In the formula, R 1 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, without an aliphatic unsaturated bond, and R 2 is a general formula —CfH2fO(CgH2gOh)R3 (R 3 ) is an organic group represented by ). x and y are positive numbers satisfying 0 ≤ x < 3.0 and 0 < y < 3.0, respectively, and 0 < x + y ≤ 3.0, preferably x is 0.1 to 2, y is 0.2 to 2, and x + y is 0.3 to 3. Furthermore, it is preferable that the polyoxyethylene content in the polyoxyalkylene-modified silicone is 30 to 80% by mass.

[0053] The above-mentioned silicone compound (E) may have the structure shown in the following structural formula (II). [In the formula, R ２ R is a hydrogen or methyl group. ３ [where m is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is 2 to 4, n is 0 to 28, X is 0 to 1.5, and Y is 0.5 to 1.5.]

[0054] For example, silicone-based compound (E) is １ H-NMR and ２９ It can be shown as the average structural formula obtained from Si-NMR.

[0055] When the silicone compound (E) is represented by the above structural formula (II), for example, m may be 2.5 or more and 3.5 or less, n may be 1 or more and 20 or less, X may be 0 or more and 1.2 or less, and Y may be 0.8 or more and 1.2 or less.

[0056] The above-mentioned silicone-based compound (E) may include, but is not limited to, those shown in the following structural formulas (1) to (3).

[0057]

[0058]

[0059]

[0060] The mass-average molecular weight of the silicone compound (E) may be between 350 and 1500, preferably between 350 and 1250, 400 and 1250, and more preferably between 400 and 900. When the mass-average molecular weight is within the above range, a smooth and highly transparent easy-adhesion layer can be formed on the film surface. Furthermore, the occurrence of unevenness caused by the easy-adhesion layer can be suppressed. In addition, adhesion to the substrate and functional films (functional layers) laminated in subsequent processes can be maintained. Moreover, because it has a relatively low molecular weight, it is thought that the environmental burden can also be reduced.

[0061] The silicone compound (E) is dissolved in solvent (D) (preferably water) at a concentration of 5% by mass. The haze of the solution may be 0% or more and 5% or less, preferably 0% or more and 4% or less. The haze of the solution may be 0.1% or more, or 0.2% or more. The haze of the solution may be 0.1% or more and 5%, 0.1% or more and 4%, 0.2% or more and 5%, or 0.2% or more and 4% or less. When the haze is within the above range, a highly transparent, easily adhesive film with suppressed unevenness can be obtained. The water used for measurement under these conditions has a surface tension of approximately 72 mN / m. By including a silicone compound under these conditions, when preparing a composition containing polyester resin (A), urethane resin (B), crosslinking agent (C), solvent (D), and silicone compound (E), phase separation of the components can be suppressed, resulting in a more uniform, highly transparent, and easily adhesive film.

[0062] The content of the silicone compound (E) in the coating solution (composition for forming an easily adhesive layer) may be 0.01% to 2.00% by mass, 0.05% to 2.00% by mass, 0.1% to 2.00% by mass, 0.01% to 1.90% by mass, etc., based on 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the coating solution. Preferably, it is 0.05% to 1.90% by mass, 0.1% to 1.90% by mass, etc., and more preferably 0.05% to 1.50% by mass, 0.1% to 1.30% by mass, etc. When the content of the silicone compound (E) is within the above range, a smooth and highly transparent easily adhesive layer can be formed on the film surface. Furthermore, the occurrence of unevenness caused by the easily adhesive layer can be suppressed. In addition, adhesion to the base film and the functional film (functional layer) laminated in a subsequent process can be maintained.

[0063] (Fluorine-based compound) The fluorine-based compound may be an organofluorine compound (PFAS), such as PFOS (perfluorooctanesulfonic acid) or PFOA (perfluorooctanoic acid), and may be used alone or in combination of two or more. The content of the fluorine-based compound in the solid content of the easy-adhesion layer forming composition may be 100 ppm or less per 100 parts by mass of the total solid content of polyester resin (A) and urethane resin (B), preferably 75 ppm or less, and more preferably 50 ppm or less. The content of the fluorine-based compound may be 0.1 ppm or more per 100 parts by mass of the total solid content of polyester resin (A) and urethane resin (B). The content of the fluorine-based compound may be substantially 0 ppm per 100 parts by mass of the total solid content of polyester resin (A) and urethane resin (B), in which case the fluorine-based compound may be included as a contaminant component. The content of the fluorinated compound may be 0 ppm to 100 ppm, 0 ppm to 75 ppm, 0 ppm to 50 ppm, 0.1 ppm to 100 ppm, 0.1 ppm to 75 ppm, 0.1 ppm to 50 ppm, etc., per 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B). By keeping the content of the fluorinated compound at 100 ppm or less per 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B), adverse effects that may occur due to the interaction between the silicone compound (E) and the fluorinated compound can be reduced, and it is presumed that adverse optical effects, for example, can also be suppressed. For example, by keeping the content of the fluorinated compound within the above range, the occurrence of unevenness caused by the easy-adhesion layer can be suppressed, and a highly transparent, easy-adhesion film can be obtained. In addition, adhesion to the substrate and functional films (functional layers) laminated in subsequent processes can be maintained. Furthermore, adverse effects on ecosystems can be suppressed. By having a fluorine-based compound content of 100 ppm or less, its extremely high surface tension-reducing effect imparts wettability and liquid leveling properties during drying to the coated easy-adhesion layer-forming composition, thereby suppressing the occurrence of unevenness caused by the easy-adhesion layer. The solid content of the easy-adhesion layer-forming composition is obtained by removing the solvent in the easy-adhesion layer-forming composition through drying or other means.In this invention, a fluorine content within the above range can be achieved by including a silicone-based compound. Furthermore, for example, in the manufacturing process and equipment for easily adhesive films, a fluorine content within the above range can be achieved by minimizing the use of fluorine-based compounds.

[0064] (Fluorine content) In one embodiment, the fluorine content obtained by immersing the easy-to-adhere film in 500 ml of ultrapure water at 25°C for 24 hours and then analyzing it with EPA method 1621 may be 5.0 μg-F / L or less, 3.0 μg-F / L or less, 0.1 to 5.0 μg-F / L or less, or 0.1 to 3.0 μg-F / L or less. It is presumed that by having a fluorine content within the above range, adverse effects that may occur due to the interaction between the silicone compound and the fluorine compound can be reduced, and adverse optical effects, for example, can also be suppressed. For example, by having the fluorine compound content within the above range, the occurrence of unevenness caused by the easy-to-adhere layer can be suppressed, and a highly transparent easy-to-adhere film can be obtained.

[0065] (High refractive index particles (particle A)) In easily adhesive polyester films, it is preferable that the coating layer (easily adhesive layer) contains high refractive index particles. When the coating layer contains high refractive index particles, the refractive index difference between the base film and the coating layer, and the refractive index difference between the coating layer and the hard coat layer, becomes smaller, making it suitable for optical applications. The refractive index becomes higher when the dicarboxylic acid component of the polyester resin constituting the coating layer contains aromatic dicarboxylic acids (especially 2,6-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid dimethyl). For this reason, an easily adhesive polyester film having a polyester resin containing aromatic dicarboxylic acid components and an easily adhesive layer containing high refractive index particles is particularly suitable for optical applications.

[0066] As particle A, metal oxide particles with a refractive index of 1.7 or higher are preferred. Such metal oxide particles include TiO ２ (Refractive index 2.7), ZnO (Refractive index 2.0), Sb ２ O ３ (Refractive index 1.9), SnO ２ (Refractive index 2.1), ZrO ２ (Refractive index 2.4), Nb ２ O５ (Refractive index 2.3), CeO ２ (Refractive index 2.2), Ta ２ O ５ (Refractive index 2.1), Y ２ O ３ (Refractive index 1.8), La ２ O ３ (Refractive index 1.9), In ２ O ３ (Refractive index 2.0), Cr ２ O ３ Examples include particles with a refractive index of 2.5, and composite oxide particles containing these metal atoms.

[0067] The lower limit of the refractive index of particle A is preferably 1.7, more preferably 1.75. The upper limit of the refractive index of particle A is preferably 3.0, more preferably 2.7, and even more preferably 2.5. By setting the refractive index of particle A within the above range, a good balance can be achieved between low interference, transparency, and adhesion to the substrate film.

[0068] The composite oxide particles used as particle A are TiO ２ / ZnO particles (zirconia / titania mixed particles) are preferred. Zirconia / titania mixed particles are a group of particles containing both zirconia and titania in an aggregate state in which zirconia and titania are dispersed individually in a single liquid and do not form a composite. Of course, in the coated layer, the liquid component is almost completely evaporated during the drying and curing processes. The inclusion of such particles A in the coated layer provides an excellent balance of slipperiness and transparency, ensuring high transparency and low interference. The liquid here is preferably an aqueous liquid in order to facilitate the formation of the coated layer using the so-called in-line coating method described later.

[0069] The zirconia / titania mixed particles may contain other components besides zirconia / titania, and these other components may be inorganic or organic particles, and are not particularly limited, but examples include inorganic particles that are inert to polyester, such as calcium carbonate, calcium phosphate, and barium sulfate.

[0070] The average particle size of particle A is preferably 5 nm or larger, more preferably 10 nm or larger, even more preferably 15 nm or larger, and particularly preferably 20 nm or larger. An average particle size of particle A of 5 nm or larger is preferable because it is less likely to aggregate.

[0071] The average particle size of particle A is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, and particularly preferably 60 nm or less. An average particle size of particle A of 200 nm or less is preferable for good transparency. The average particle size of particle A can be 5 to 200 nm, 5 to 150 nm, 5 to 100 nm, 5 to 60 nm, 10 to 200 nm, 10 to 150 nm, 10 to 100 nm, 10 to 60 nm, 15 to 200 nm, 15 to 150 nm, 15 to 100 nm, 15 to 60 nm, 20 to 200 nm, 20 to 150 nm, 20 to 100 nm, 20 to 60 nm, etc.

[0072] (Lubricant particles (particle B)) In easily adhesive polyester films, it is preferable that the coating layer (easily adhesive layer) contains lubricant particles (particle B).

[0073] Particle B can include (1) inorganic particles such as silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, magnesium carbonate, magnesium hydroxide, and (2) organic particles such as acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallyl phthalate, and polyester. However, silica is particularly preferred to provide the coating layer with appropriate slipperiness.

[0074] The average particle size of particle B is preferably 200 nm or more, more preferably 250 nm or more, even more preferably 300 nm or more, and particularly preferably 350 nm or more. An average particle size of particle B of 200 nm or more is preferable because it is less likely to aggregate and ensures good lubricity.

[0075] The average particle size of particle B is preferably 2000 nm or less, more preferably 1500 nm or less, even more preferably 1000 nm or less, and particularly preferably 700 nm or less. An average particle size of particle B of 2000 nm or less is preferable because transparency is maintained and particle shedding is suppressed. The average particle size of particle B can be 200 to 2000 nm, 200 to 1500 nm, 200 to 1000 nm, 200 to 700 nm, 250 to 2000 nm, 250 to 1500 nm, 250 to 1000 nm, 250 to 700 nm, 300 to 2000 nm, 300 to 1500 nm, 300 to 1000 nm, 300 to 700 nm, 350 to 2000 nm, 350 to 1500 nm, 350 to 1000 nm, 350 to 700 nm, etc.

[0076] The surfaces of particles A and B may be treated. Surface treatment methods include physical surface treatments such as plasma discharge treatment and corona discharge treatment, and chemical surface treatments using coupling agents, but the use of coupling agents is preferred. Organoalkoxymetal compounds (e.g., titanium coupling agents, silane coupling agents) are preferably used as coupling agents. Silane coupling treatment is particularly effective when particle B is silica. The surface treatment agent for particle B may be used to pre-treat the surface before preparing the coating solution, or it may be added as an additive during the preparation of the coating solution to be incorporated into the layer. Of course, it may also be used on particle A.

[0077] The content of particle A in the coating layer is preferably 2% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and particularly preferably 5% by mass or more. When the content of particle A in the coating layer is 2% by mass or more, the refractive index of the coating layer can be kept high, and low coherence can be effectively obtained, which is preferable.

[0078] The content of particles A in the coating layer is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less. A content of particles A in the coating layer of 50% by mass or less is preferable because it maintains film-forming properties. The content of particles A in the coating layer can be 2 to 50% by mass, 2 to 40% by mass, 2 to 30% by mass, 2 to 20% by mass, 3 to 50% by mass, 3 to 40% by mass, 3 to 30% by mass, 3 to 20% by mass, 4 to 50% by mass, 4 to 40% by mass, 4 to 30% by mass, 4 to 20% by mass, 5 to 50% by mass, 5 to 40% by mass, 5 to 30% by mass, 5 to 20% by mass, etc.

[0079] The content of particle B in the coating layer is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. A particle B content of 0.01% by mass or more in the coating layer is preferable because it maintains appropriate slipperiness.

[0080] The content of particle B in the coating layer is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less. When the content of particle B in the coating layer is 2% by mass or less, the haze is kept low, which is preferable in terms of transparency. The content of particle B in the coating layer may be 0.01 to 2% by mass, 0.01 to 1.5% by mass, 0.01 to 1% by mass, 0.05 to 2% by mass, 0.05 to 1.5% by mass, 0.05 to 1% by mass, 0.1 to 2% by mass, 0.1 to 1.5% by mass, 0.1 to 1% by mass, etc.

[0081] (Other Components) The composition for forming the easy-adhesion layer may contain other components in addition to the polyester resin (A), urethane resin (B), crosslinking agent (C), solvent (D), and silicone compound (E), as long as they do not hinder the effects of the present invention. Other components include binder resins other than polyurethane resins having a polycarbonate skeleton, crosslinking agents other than crosslinking agent (C), fluorescent dyes, fluorescent whitening agents, plasticizers, ultraviolet absorbers, pigment dispersants, antifoaming agents, defoaming agents, and preservatives. The composition for forming the easy-adhesion layer may contain solvents other than water, and the mass of solvent remaining in the easy-adhesion layer formed after drying and curing of the coating solution is extremely small. When calculating the composition of each component from the coating solution, the mass of the remaining solvent does not necessarily have to be included in the total solid content mass of the coating layer. In the composition description in the examples, the total solid content mass of the coating layer does not include the mass of the remaining solvent.

[0082] The thickness of the easy-adhesion layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, and particularly preferably 0.05 μm or more. A thickness of 0.001 μm or more of the easy-adhesion layer is preferable because it results in good adhesion of the functional layer laminated to the easy-adhesion layer.

[0083] The thickness of the easy-adhesion layer is preferably 2 μm or less, more preferably 1 μm or less, even more preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. A thickness of 2 μm or less for the coating layer is preferable because it does not risk causing blocking. The thickness of the easy-adhesion layer can be 0.001 to 2 μm, 0.001 to 1 μm, 0.001 to 0.8 μm, 0.001 to 0.5 μm, 0.01 to 2 μm, 0.01 to 1 μm, 0.01 to 0.8 μm, 0.01 to 0.5 μm, 0.02 to 2 μm, 0.02 to 1 μm, 0.02 to 0.8 μm, 0.02 to 0.5 μm, 0.05 to 2 μm, 0.05 to 1 μm, 0.05 to 0.8 μm, 0.05 to 0.5 μm, etc.

[0084] As for the coating method of the coating solution, both the so-called in-line coating method, in which the coating solution is applied simultaneously with the formation of the polyester substrate film, and the so-called off-line coating method, in which the coating solution is applied with a coater after the polyester substrate film has been formed, can be applied. However, the in-line coating method is more efficient and therefore preferable.

[0085] As for the coating method, any known method can be used to apply the coating solution to the polyethylene terephthalate (hereinafter abbreviated as PET) film. Examples include the reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. These methods can be used individually or in combination.

[0086] The drying temperature after coating is also preferable to be between 80°C and 250°C, although this depends on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, and the solid content concentration.

[0087] One embodiment of the present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0088] (Evaluation Method) (1) Structure and Molecular Weight of Silicone Compounds and Fluorine-Based Compounds The structure of the silicone compound was identified using a BRUKER AVANCE-NEO600 NMR spectrometer, performing 1H-NMR measurements at a resonance frequency of 600.13 MHz and 29Si-NMR measurements at a resonance frequency of 119.22 MHz. For 1H-NMR, 10 mg of the sample was dissolved in 0.6 ml of deuterated chloroform, and the solution was packed into an NMR tube for measurement. Deuterated chloroform was used as the locking solvent, with a waiting time of 1 second, a data acquisition time of 4 seconds, and 128 integration cycles. For 29Si-NMR, 100 mg of the sample was dissolved in 0.6 ml of deuterated chloroform with 1 wt% chromium(III) acetylacetonate added, and the solution was packed into an NMR tube for measurement using the inverse gate decoupler method. Deuterated chloroform was used as the locking solvent, with a waiting time of 7.5 seconds, a data acquisition time of 1.5 seconds, and 4000 integration cycles.

[0089] (2) Haze of the aqueous solution of the silicone compound An aqueous solution of the silicone compound was prepared by dissolving it in water at a concentration of 5% by mass. The haze of this aqueous solution was measured using a turbidimeter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136:2000.

[0090] (3) The resin composition of the copolymer polyester resin for the easy-adhesion layer is dissolved in deuterated chloroform and analyzed using a BRUKER AVANCE-NEO600 NMR spectrometer. １ ¹H-NMR analysis was performed, and the molar percentage ratio of each component was determined from the integral ratio.

[0091] (4) 0.03 g of the number-average molecular weight resin of copolymer polyester resin for easy adhesion layer was dissolved in 10 ml of tetrahydrofuran, and the number-average molecular weight was measured using a GPC-LALLS low-angle light scattering photometer LS-8000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene) at a column temperature of 30°C, a flow rate of 1 ml / min, and using columns (Resonac Corporation's Shodex KF-802, 804, 806).

[0092] (5) Evaluation of unevenness and smoothness of easy-to-adhere film The film was cut to A4 size, and the unevenness and smoothness of the easy-to-adhere layer coating surface was visually inspected in a dark room under fluorescent light illumination and evaluated on a 5-point scale based on the following criteria. 5: Both unevenness and smoothness were good. 4: Slight unevenness or slight irregularity in smoothness was observed in a part of the coating surface. 3: Easily visible unevenness or easily visible irregularity in smoothness was observed in a part of the coating surface. 2: Unevenness or irregularity in smoothness was observed throughout the entire coating surface. 1: Significant unevenness or significant irregularity in smoothness was observed throughout the entire coating surface.

[0093] (6) Evaluation of adhesion between the easy-to-adhere film and the hard coat layer (6-1) Formation of the hard coat layer The hard coat coating liquid A described below is applied to the easy-to-adhere layer of the easy-to-adhere polyester film using a wire bar so that the coating thickness after drying is 2 μm, and dried with hot air at a temperature of 80°C for 60 seconds at an output of 120 W / cm². ２A hard coat layer was formed by passing the device at a speed of 10 m / min at a position 20 cm under a high-pressure mercury lamp, and a hard coat film was obtained. The refractive index of the hard coat layer was 1.48.

[0094] (6-2) Hard Coating Solution A The materials for the hard coating solution listed below were mixed in the mass ratio shown below and stirred for 30 minutes or more to dissolve. Then, undissolved material was removed using a filter with a nominal filtration accuracy of 1 μm to prepare hard coating solution A. (Hard Coating Solution A) ・Methyl ethyl ketone 64.48% by mass ・Pentaerythritol triacrylate 11.45% by mass (Shin Nakamura Chemical Co., Ltd., NK Ester A-TMM-3LM-N, 3 functional groups) ・Tripropylene glycol diacrylate 5.73% by mass (Shin Nakamura Chemical Co., Ltd., NK Ester APG-200, 2 functional groups) ・Dimethylaminoethyl methacrylate 5.72% by mass (Kyoeisha Chemical Co., Ltd., Light Ester DM, 1 functional group) ・Silica microparticles 11.45% by mass (Nissan Chemical Industries, Ltd., MEK-ST-L, solid content ratio: 30% by mass, average particle size: 50 nm) ・Photopolymerization initiator 1.14% by mass (Irgacure 184, Ciba Specialty Chemicals) ・Silicone-based surfactant 0.03% by mass (DC57, Toray Dow Corning Co., Ltd.)

[0095] (6-3) Measurement of Hard Coat Layer Adhesion A grid of cuts was made in the hard coat layer of the obtained hard coat film using a utility knife. Specifically, 100 grid-like cuts penetrating the hard coat layer and reaching the base film were made on the hard coat layer surface using a cutter guide with a gap spacing of 2 mm. Next, cellophane adhesive tape (Nichiban Co., Ltd., No. 405; 24 mm wide) was attached to the grid-like cut surface, and the tape was rubbed with an eraser to ensure complete adhesion. After that, the cellophane adhesive tape was peeled vertically from the hard coat layer surface, and the number of squares that peeled off from the hard coat layer surface of the base film was visually counted. The adhesion between the hard coat layer and the base film was then calculated using the following formula. Note that partially peeled squares were also counted as peeled squares. Adhesion (%) = (1 - number of peeled squares / 100) × 100

[0096] (7) Evaluation of fluorine leaching from easy-to-adhere film An A4-sized easy-to-adhere film was immersed in 500 ml of ultrapure water at 25°C for 24 hours, and then analyzed using EPA method 1621 to calculate the amount of fluorine leached (μg-F / L).

[0097] (8) Fluorine compound content (ppm) The fluorine compound content was calculated using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0098] (Preparation of polyurethane resin aqueous dispersions U01-U04, U07-U09, and U12 for easy-adhesion layers) In a four-necked flask equipped with a stirrer, a Liebig condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 43.76 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, 153.43 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2000, and 83.00 parts by mass of methyl ethyl ketone as an amine catalyst and solvent were added and stirred at 75°C for 10 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution reached the predetermined amine equivalent. Next, after the reaction solution was cooled to 40°C, 8.81 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The polyurethane prepolymer solution was then added and dispersed in water while stirring at 2000 min⁻¹. Subsequently, under reduced pressure, the methyl ethyl ketone and some of the water were removed to obtain the polyurethane resin aqueous dispersion for easy-adhesion layers (U01) with a solid content of 37.0% by mass, as shown in Table 1. Similarly, polyurethane resin aqueous dispersions for easy-adhesion layers (U02-U04, U07-U09, U12) were obtained using the raw materials and quantities shown in Table 1.

[0099] (Preparation of polyurethane resin aqueous dispersions U05 and U06 for easy-adhesion layers) In a four-necked flask equipped with a stirrer, a Liebig condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 22.10 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 3.00 parts by mass of dimethylolbutanoic acid, 1.00 part by mass of neopentyl glycol, 74.20 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2000, and 85.00 parts by mass of methyl ethyl ketone as an amine catalyst and solvent were added and stirred at 75°C for 10 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution reached the predetermined amine equivalent. Next, 2.00 parts by mass of trimethylolpropane was added and stirred at 75°C for 2 hours under a nitrogen atmosphere, and it was confirmed again that the reaction solution reached the predetermined amine equivalent. Next, after the reaction solution was cooled to 40°C, 4.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The polyurethane prepolymer solution was then added and dispersed in water while stirring at 2000 r / min. Subsequently, under reduced pressure, the methyl ethyl ketone and a portion of the water were removed to obtain the polyurethane resin aqueous dispersion for easy-adhesion layers (U05) with a solid content of 37.0% by mass, as shown in Table 1. Similarly, polyurethane resin aqueous dispersion for easy-adhesion layers (U06) was obtained using the raw materials and quantities shown in Table 1.

[0100] (Preparation of polyurethane resin aqueous dispersions U10 and U11 for easy-adhesion layers) In a four-necked flask equipped with a stirrer, a Liebig condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 40.10 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 53.96 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 1000, and 83.50 parts by mass of methyl ethyl ketone as an amine catalyst and solvent were added and stirred at 75°C for 10 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution reached the predetermined amine equivalent. Next, 2.00 parts by mass of trimethylolpropane was added and stirred at 75°C for 2 hours under a nitrogen atmosphere, and it was confirmed again that the reaction solution reached the predetermined amine equivalent. Next, this reaction solution was cooled to 40°C to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The polyurethane prepolymer solution was then added and dispersed in water while stirring at 2000 min⁻¹. Subsequently, under reduced pressure, the methyl ethyl ketone and some of the water were removed to obtain the polyurethane resin aqueous dispersion for easy-adhesion layers (U10) with a solid content of 37.0% by mass, as shown in Table 1. Similarly, polyurethane resin aqueous dispersion for easy-adhesion layers (U11) was obtained using the raw materials and quantities shown in Table 1.

[0101]

[0102] (Preparation of copolymer polyester resins e01 to e05 for easy-adhesion layers) In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, 342.0 parts by mass of dimethyl 2,6-naphthalenedicarboxylate, 35.0 parts by mass of dimethyl terephthalate, 35.5 parts by mass of dimethyl-5-sodium sulfoisophthalate, 198.6 parts by mass of ethylene glycol, 17.3 parts by mass of diethylene glycol, 118.2 parts by mass of 1,6-hexanediol, and 0.4 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was carried out at 160°C to 220°C for 4 hours. Furthermore, 60.7 parts by mass of sebaciic acid was added, and an esterification reaction was carried out. The temperature was then raised to 255°C, the reaction system was gradually reduced in pressure, and the reaction was carried out under a reduced pressure of 30 Pa for 1 hour and 40 minutes to obtain a simple yellow transparent copolymer polyester resin for easy-adhesion layers. The monomer composition and number-average molecular weight of copolymer polyester resin for easy adhesion layer (e01) are shown in Table 2. Copolymer polyester resins e02 to e05 for easy adhesion layer were obtained in the same manner using the raw materials and quantities shown in Table 2.

[0103]

[0104] (Preparation of copolymer polyester resin aqueous dispersions E01 to E05 for easy-adhesion layer) 30 parts by mass of copolymer polyester resin for easy-adhesion layer (e01) and 15 parts by mass of ethylene glycol-n-butyl ether were placed in a reactor equipped with a stirrer, thermometer, and reflux device, and heated and stirred at 110°C to dissolve the resin. After the resin had completely dissolved and become a polyester resin solution, 55 parts by mass of water were gradually added to the polyester resin solution while stirring. After the addition, the liquid was cooled to room temperature while stirring to obtain an aqueous dispersion of copolymer polyester resin for easy-adhesion layer (E01) with a solid content of 25% by mass and a milky white appearance. E02 to E05, which are milky white copolymer polyester resin aqueous dispersions for easy-adhesion layer, were obtained in the same manner except that copolymer polyester resin e01 was changed to e02 to e05. All of the copolymer polyester resin aqueous dispersions for easy-adhesion layer E01 to E05 had a solid content of 25% by mass.

[0105] (Production of Block Polyisocyanate Crosslinking Agent) 100 parts by mass of a polyisocyanate compound having an isocyanurate structure derived from hexamethylene diisocyanate (Duranate TPA, manufactured by Asahi Kasei Chemicals), 55 parts by mass of propylene glycol monomethyl ether acetate, and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) were charged into a flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was maintained at 70°C for 4.2 hours under a nitrogen atmosphere. Subsequently, the reaction solution temperature was lowered to 50°C, and 47 parts by mass of methyl ethyl ketoxime were added dropwise. The infrared spectrum of the reaction solution was measured to confirm the disappearance of absorption of the isocyanate group, and a block polyisocyanate aqueous dispersion with a solid content of 40% by mass was obtained.

[0106] (Production of Zirconia Particle Aqueous Dispersion) Referring to Example 8 of Japanese Patent Publication No. 2008-290896, a zirconia particle aqueous dispersion was produced as follows: 2283.6 g of pure water and 403.4 g of oxalic acid dihydrate were placed in a 3-liter glass container and heated to 40°C to prepare a 10.72% by mass oxalic acid aqueous solution. While stirring this aqueous solution, zirconium oxycarbonate powder (ZrOCO) was added. ３ , manufactured by AMR International Corp., ZrO ２ It contains 39.76% by mass when converted to ZrO. 495.8 g was gradually added and mixed for 30 minutes, then heated at 90°C for 30 minutes. Next, 1747.2 g of 25.0% by mass tetramethylammonium hydroxide aqueous solution (manufactured by Tama Chemical Industry Co., Ltd.) was gradually added over 1 hour. At this point the mixture was in a slurry state, and ZrO ２ The slurry contained 4.0% by mass in conversion. This slurry was transferred to a stainless steel autoclave container and subjected to hydrothermal treatment at 145°C for 5 hours. The product after this hydrothermal treatment was completely sol-like with no undissolved gelatin. The obtained sol contained 4.0% by mass as ZrO2, had a pH of 6.8, and an average particle size of 19 nm as measured by dynamic light scattering. Furthermore, the transmittance measured by adjusting the sol to a ZrO2 concentration of 2.0% by mass with pure water was 88%. When the particles were observed with a transmission electron microscope, ZrO2 particles of approximately 7 nm were found. ２ Most of the particles were aggregated primary particles. ZrO obtained by the above hydrothermal treatment２ 4000 g of zirconia sol with a concentration of 4.0% by mass is washed and concentrated using an ultrafiltration apparatus while gradually adding pure water, and then ZrO ２ Concentration 13.1% by mass, pH 4.9, ZrO ２ 953 g of zirconia sol with a transmittance of 76% at a concentration of 13.1% by mass was obtained. ZrO was obtained by performing the above washing and concentration. ２ To 300 g of 13.1% by mass zirconia sol, 3.93 g of 20% by mass citric acid aqueous solution and 11.0 g of 25% by mass tetramethylammonium hydroxide aqueous solution were added, and then the mixture was further concentrated using an ultrafiltration apparatus to obtain ZrO ２ 129 g of a high-concentration zirconia sol with a concentration of 30.5% by mass was obtained. This obtained high-concentration zirconia sol had a pH of 9.3 and an average particle size of 19 nm as determined by dynamic light scattering. Furthermore, this zirconia sol was free of sediment and remained stable for more than one month under conditions of 50°C.

[0107] (Production of Titania Particle Aqueous Dispersion) Referring to Example 1 of Japanese Patent Publication No. 2011-132484, titania particles were produced as follows: Titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) was converted to TiO ２ A white slurry with a pH of 9.5 was prepared by mixing 12.09 kg of an aqueous titanium tetrachloride solution containing 7.75% by mass (based on the conversion standard) with 4.69 kg of aqueous ammonia (manufactured by Ube Industries, Ltd.) containing 15% by mass of ammonia. Next, this slurry was filtered and washed with pure water to obtain 9.87 kg of hydrated titanate cake with a solid content of 10% by mass. To this cake, 11.28 kg of aqueous hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) containing 35% by mass of hydrogen peroxide and 20.00 kg of pure water were added, and the mixture was heated at 80°C for 1 hour with stirring. A further 57.52 kg of pure water was added to obtain 98.67 kg of an aqueous titanium peroxide solution containing 1% by mass of titanate peroxide (based on the TiO2 conversion standard). This aqueous titanium peroxide solution was transparent yellowish-brown and had a pH of 8.5. Next, 4.70 kg of cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 98.67 kg of the titanic acid peroxide aqueous solution, and potassium stannate (manufactured by Showa Chemical Co., Ltd.) was added to this mixture. ２12.33 kg of an aqueous potassium stanate solution containing 1% by mass (based on conversion standards) was gradually added under stirring. Next, the cation exchange resin that had incorporated potassium ions and other elements was separated and placed in an autoclave (manufactured by Pressure Glass Industry Co., Ltd., 120 L) and heated at 165°C for 18 hours. Next, the obtained mixed aqueous solution was cooled to room temperature and then concentrated using an ultrafiltration membrane apparatus (manufactured by Asahi Kasei Corporation, ACV-3010) to obtain 9.90 kg of an aqueous dispersion sol containing titanium-based fine particles with a solid content of 10% by mass. When the solids contained in the sol thus obtained were measured by the method described above, they were found to be titanium-based fine particles (primary particles) consisting of a composite oxide containing titanium and tin, having a rutile-type crystalline structure. Furthermore, when the content of metal components contained in these titanium-based fine particles was measured, the content of each metal component on an oxide basis was found to be TiO ２ 87.2% by mass, SnO ２ 11.0% by mass, and K ２ The concentration of O was 1.8% by mass. The pH of the mixed aqueous solution was 10.0. Furthermore, the aqueous dispersion sol containing the titanium-based fine particles was a transparent milky white, and the average particle size of the titanium-based fine particles contained in this aqueous dispersion sol, measured by dynamic light scattering, was 35 nm. Moreover, the distribution frequency of coarse particles with a particle size of 100 nm or more was 0%. Furthermore, the refractive index of the obtained titanium-based fine particles could be considered to be 2.42.

[0108] (Production of Zirconia / Titania Mixed Particle Aqueous Dispersion) By mixing the zirconia particles and titania particles obtained above in a mass ratio of 75 / 25, zirconia / titania mixed particles (average particle size 23 nm) with a solid content of 13% by mass were prepared.

[0109] (Example 1) (Silicone compound-1) A polyether-modified silicone with a molecular weight of 670, structural formula (II) m=3.0, n=8.5, X=0, Y=1.0, and a solid content concentration of 100% was used as silicone compound-1.

[0110] (Raw materials for coating liquid for easy adhesion layer formation (composition for easy adhesion layer formation)) ・Silicone compound-1 ・Polyurethane resin aqueous dispersion ((U01), solid content concentration 37% by mass) ・Polyester resin aqueous dispersion ((E01), solid content concentration 25% by mass) ・Blocked polyisocyanate crosslinking agent (solid content concentration 40% by mass) ・Particle A aqueous dispersion (zirconia / titania mixed particle aqueous dispersion, solid content concentration 13% by mass) ・Particle B aqueous dispersion (silica sol with average particle size of 450 nm, solid content concentration 4% by mass)

[0111] (Preparation of coating solution for easy adhesion layer formation) A coating solution was prepared by mixing and stirring the raw materials shown in the composition below. The content of the silicone compound in the coating solution, calculated from this composition, was 0.408% by mass per 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the coating solution, and the content of the fluorine compound in the solid content of the coating solution was 0 ppm by mass per 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the coating solution. ・Silicone compound-1 0.030 parts by mass ・Water 37.760 parts by mass ・Isopropyl alcohol 31.780 parts by mass ・Polyurethane resin aqueous dispersion 3.960 parts by mass ・Polyester resin aqueous dispersion 8.800 parts by mass ・Blocked polyisocyanate crosslinking agent 5.500 parts by mass ・Particle A aqueous dispersion 10.990 parts by mass ・Particle B aqueous dispersion 0.910 parts by mass

[0112] (Manufacturing of easily adhering polyester film) As the raw material polymer for the base film, PET resin pellets with an intrinsic viscosity (solvent: phenol / tetrachloroethane = 60 / 40 (volume ratio)) of 0.62 dl / g and substantially free of particles were used. The raw material polymer was dried at 135°C for 6 hours under reduced pressure of 133 Pa. Thereafter, it was supplied to an extruder and melt-extruded into a sheet at approximately 280°C, and rapidly cooled and solidified on a rotating cooling metal roll maintained at a surface temperature of 20°C to obtain an unstretched PET sheet.

[0113] This unstretched PET sheet was heated to 100°C using a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction using a roll group with different peripheral speeds to obtain a uniaxially oriented PET film.

[0114] Next, the coating solution for forming the easy-adhesion layer was applied to one side of the PET film by a roll-coating method, and then dried at 80°C for 15 seconds. The amount of coating solution applied was such that the amount of the easy-adhesion layer after drying following final stretching was 0.12 g / m². ２ The film was adjusted to achieve the following. Subsequently, it was stretched to 4.0 times its original width in the width direction at 150°C using a tenter, and with the length in the width direction of the film fixed, it was heated at 230°C for 0.5 seconds, and then subjected to a 3% widthwise relaxation treatment at 230°C for 10 seconds to obtain an optically-grade easily adhesive polyester film with a thickness of 38 μm. The thickness of the easily adhesive layer was 80 nm. This easily adhesive polyester film was subjected to various evaluations. Furthermore, a hard coat layer was formed on this adhesive polyester film using the method described in section (6-1) "Formation of Hard Coat Layer" above to obtain a hard coat film. This hard coat film was subjected to evaluation of the adhesion of the hard coat layer.

[0115] (Examples 2, 3, Comparative Examples 4, 5) Easy-adhesion polyester films and hard coat films were obtained in the same manner as in Example 1, except that the concentration of silicone compound-1 in the solid content of the coating solution for forming the easy-adhesion layer was changed to the concentration shown in Table 3, and these were subjected to various evaluations.

[0116] (Examples 4-15, Comparative Examples 1-3, 6-20) Easy-adhesion polyester films and hard coat films were obtained in the same manner as in Example 1, except that the type and amount of silicone-based compound used in the coating solution for forming the easy-adhesion layer were changed to the types and amounts shown in Tables 3 and 4, and these were subjected to various evaluations. In Comparative Examples 1-3, DIC Corporation's fluorine-based surfactant F-470 was used as the fluorine-based surfactant.

[0117] (Examples 16-31) Easy-adhesion polyester films and hard coat films were obtained in the same manner as in Example 1, except that the types and amounts of polyurethane resin aqueous dispersions, polyester resin aqueous dispersions, and silicone compounds used in the coating solution for forming the easy-adhesion layer were changed to the types and amounts shown in Table 3, and these were subjected to various evaluations.

[0118] (Comparative Examples 21-36) Easy-adhesion polyester films and hard coat films were obtained in the same manner as in Example 1, except that the types and amounts of polyurethane resin aqueous dispersions, polyester resin aqueous dispersions, and silicone compounds used in the coating solution for forming the easy-adhesion layer were changed to those shown in Table 4. These were then subjected to various evaluations. As the fluorine-based surfactant, DIC Corporation's fluorine-based surfactant F-470 was used.

[0119] The results of the physical property evaluation of the films obtained in the examples and comparative examples are shown in Tables 3 and 4. The polyester films obtained in the examples and comparative examples had no problems in terms of winding and handling properties.

[0120]

[0121]

[0122] According to the present invention, it is possible to provide an easily adhesive polyester film that exhibits less haze, superior uniformity and smoothness compared to easily adhesive polyester films using fluorine-based surfactants, and has hard coat layer adhesion equivalent to that of easily adhesive polyester films using fluorine-based surfactants.

Claims

1. An easily adhesive polyester film having a polyester film as a base film and an easily adhesive layer on at least one surface of the base film, wherein the easily adhesive layer is formed by curing a composition containing a polyester resin (A), a urethane resin (B), a crosslinking agent (C), a solvent (D), and a silicone compound (E), wherein the mass average molecular weight of the silicone compound (E) is 350 or more and 1500 or less, the content of the silicone compound (E) in the composition is 0.01% by mass or more and 2.00% by mass or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition, and the content of the fluorine compound in the solid content of the composition is 100 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition.

2. The easy-to-adhere polyester film according to claim 1, wherein the mass-average molecular weight of the silicone compound (E) is 350 or more and 1250 or less, the content of the silicone compound (E) in the composition is 0.05% by mass or more and 1.50% by mass or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition, and the content of the fluorine compound in the solid content of the composition is 75 ppm or less with respect to 100 parts by mass of the total solid content of the polyester resin (A) and urethane resin (B) contained in the composition.

3. The easily adhering polyester film according to claim 1, wherein the silicone compound (E) has the property that the haze of the solution obtained by dissolving the silicone compound (E) in water at a concentration of 5% by mass is 0% or more and 5% or less.

4. The easy-to-adhere polyester film according to claim 1, wherein the amount of fluorine obtained by immersing the easy-to-adhere polyester film in 500 ml of ultrapure water at 25°C for 24 hours and then analyzing it using EPA method 1621 is 5.0 μg-F / L or less.

5. The easy-to-adhere polyester film according to claim 1, wherein the silicone compound (E) has the structure shown by the following structural formula (II). [In the formula, R ２ R is a hydrogen or methyl group. ３ [where m is hydrogen or a monovalent hydrocarbon group having 1 to 10 carbon atoms, m is 2 to 4, n is 0 to 28, X is 0 to 1.5, and Y is 0.5 to 1.5.] 6. The easy-to-adhere polyester film according to claim 1, wherein the easy-to-adhere polyester film is an environmentally friendly easy-to-adhere polyester film for optical applications.

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