Printed materials

Abstract

[Problem] To provide printed matter which has favorable adhesiveness to various ink compositions while avoiding electrostatic damage in a printing step, and which maintains favorable adhesiveness without causing degradation of the adhesiveness between an ink layer and an easily adhesive layer even when printed, and then stored in a high-temperature and high-humidity environment. [Solution] This printed matter has an easily adhesive coating layer provided on a polyester film substrate, and is formed by laminating, on the easily adhesive coating layer, at least one ink layer selected from among UV-curable ink, solvent-type ink, oxidative polymerization-type ink, thermal transfer ink ribbon, and LBP toner, wherein the nitrogen ion concentration A (at%) and the nitrogen element ratio B (at%), as obtained on the basis of the surface element distribution measurement of the surface of the easily adhesive coating layer by X-ray photoelectron spectroscopy, satisfy a specific relationship, and the contact angle θ H2O of the surface of the easily adhesive coating layer to water is within a specific range.

Description

[Technical Field]

[0001] The present invention relates to printed materials with excellent adhesion to various ink layers. More specifically, it relates to printed materials having an easily adhesive coating layer on a biaxially oriented polyester film substrate that is optimal for all types of ink layers, such as ultraviolet (UV) curing inks, solvent-based inks, oxidative polymerization inks, thermal transfer ink ribbons, and LBP toners. In particular, regarding adhesion to active energy ray curing ink layers such as ultraviolet (UV) curing inks, the present invention relates to printed materials having an easily adhesive coating layer that does not deteriorate in adhesion to the ink layer even when stored in a high-temperature, high-humidity environment after printing.

[0002] Polyester film is used as a base film in many fields, such as magnetic recording materials, packaging materials, electrical insulation materials, photosensitive materials, drafting materials, and photographic materials, due to its excellent properties including mechanical properties, electrical properties, and dimensional stability. It is especially indispensable for various commercial printing applications and labels where printing is applied to the film. However, because polyester film has poor adhesion to printing inks, it is common to provide an anchor coating layer using an easily adhesive resin. Examples of resins that make up the coating layer include polyester resins, polyurethane resins, and acrylic resins, either individually or in mixtures of two or more, or mixtures of the resin with a specific crosslinking agent (melamine, isocyanate, etc.). However, generally, both the surface of the polyester film base material and the surface of the easily adhesive coating layer provided to improve adhesion are prone to static electricity, which can pose problems related to the passability of the film-forming process and electrostatic discharge problems in the processing process (see, for example, Patent Document 1).

[0003] As a method to improve problems caused by static electricity, it is known that the coating layer is given antistatic properties by incorporating conductive polymers such as polyaniline and polypyrrole, particulate carbon black, metal powders such as nickel and copper, metal oxides such as tin oxide and zinc oxide, fibrous metal coating fibers such as brass, stainless steel and aluminum, scaly graphite, aluminum flakes and copper flakes into the coating layer.

[0004] Alternatively, it is known that a polymer-based antistatic agent having at least one sulfonic acid base or phosphate base in its molecule is incorporated into the coating and applied to the substrate film (see, for example, Patent Document 2).

[0005] In recent years, printed materials as labels have become widespread in a wide range of fields. The global food market is expanding, and food labels are becoming common not only in developed countries but also in developing countries. Furthermore, the demand for caution labels used on industrial electronic components is increasing along with the growing demand for industrial products. These printed materials are often used in high-temperature and high-humidity environments. However, when printed materials are stored in such environments, the adhesion between the ink layer and the easily adhesive coating layer of the substrate decreases, causing the printed area to peel off, and thus the label may lose its original function. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2001-348450 [Patent Document 2] Japanese Patent Publication No. 2011-156848 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a printed material having an easily adhesive coating layer on a polyester film substrate, further comprising an ink layer on the easily adhesive coating layer, which avoids electrostatic interference during the printing process, has good adhesion to various ink compositions, and maintains good adhesion between the ink layer and the easily adhesive layer without deterioration of adhesion even when stored in a high-temperature, high-humidity environment after printing. [Means for solving the problem]

[0008] The inventors of the present invention have investigated the causes of the above problems in order to solve them, and have completed the present invention. That is, the present invention consists of the following configuration. 1. A printed material having an easy-adhesion coating layer on a polyester film substrate, wherein at least one ink layer selected from UV-curable ink, solvent-based ink, oxidative polymerization ink, thermal transfer ink ribbon, and LBP toner is laminated on the easy-adhesion coating layer, wherein the nitrogen ion concentration A (at%) and nitrogen element ratio B (at%) based on surface element distribution measurement of the surface of the easy-adhesion coating layer by X-ray photoelectron spectroscopy satisfy the following formulas (i) and (ii), and the contact angle θ H2O with water on the surface of the easy-adhesion coating layer satisfies the following formula (iii). (i) A(at%) > 0.4 (ii) 2.0 ≤ B / A ≤ 5.0 (iii) 50°≦θ H2O≦70° 2. The printed article according to the first description, wherein the easily adhering coating layer is formed by curing a composition comprising a cationic antistatic agent, a polyurethane resin, and a polyester resin. 3. The printed material according to the first or second above, wherein the polyester film substrate is a white polyester film substrate containing inorganic particles and / or a thermoplastic resin incompatible with the polyester resin. [Effects of the Invention]

[0009] The present invention makes it possible to avoid electrostatic discharge problems in the printing process and to obtain various printed materials with good adhesion between the easily adhering coating layer and the ink layer. Furthermore, even when stored in a high-temperature, high-humidity environment after printing, the adhesion between the substrate and the ink layer does not deteriorate, and good adhesion is maintained. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram illustrates how to determine the nitrogen element ratio A (at%) derived from the antistatic agent and the nitrogen element ratio B (at%) derived from the polyurethane resin, based on surface element distribution measurement of the easily adhering coated layer surface by X-ray photoelectron spectroscopy in the present invention. [Modes for carrying out the invention]

[0011] (Polyester film substrate) In the present invention, the polyester resin constituting the polyester film substrate is polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polytrimethylene terephthalate, etc., as well as a copolymerized polyester resin in which a part of the diol component or dicarboxylic acid component of the above-mentioned polyester resin is replaced with the following copolymer components. For example, the copolymer components can include diol components such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, and polyalkylene glycol, and dicarboxylic acid components such as adipic acid, sebatic acid, phthalic acid, isophthalic acid, 5-sodium isophthalic acid, and 2,6-naphthalenedicarboxylic acid.

[0012] The polyester resin preferably used for the polyester film base material in the present invention is mainly selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. Among these polyester resins, polyethylene terephthalate is most preferable in terms of the balance between physical properties and cost. Further, the polyester film base material composed of these polyester resins is preferably a biaxially stretched polyester film, which can improve chemical resistance, heat resistance, mechanical strength, stiffness, etc.

[0013] The catalyst for polycondensation used in the production of the polyester resin is not particularly limited, but antimony trioxide is suitable because it is inexpensive and has excellent catalytic activity. It is also preferable to use a germanium compound or a titanium compound. Further preferable polycondensation catalysts include a catalyst containing aluminum and / or its compound and a phenolic compound, a catalyst containing aluminum and / or its compound and a phosphorus compound, and a catalyst containing an aluminum salt of a phosphorus compound.

[0014] The base polyester film used in the present invention may have a single-layer structure or a multilayer structure, but it is preferable that some or all of its layers are opaque. The optical density indicating the opacity of the polyester film is 0.3 or more, preferably 0.3 to 4.0, and particularly preferably 0.5 to 3.0. When the optical density is 0.3 or more, the printing effect becomes clear when printing is applied to the surface of the obtained polyester-coated film, which is preferable. Further, when the optical density is 4.0 or less, a more excellent printing effect can be expected, which is preferable.

[0015] The method for obtaining the optical density within the above range is not particularly limited, but it can be preferably achieved by incorporating inorganic particles into the polyester resin or a thermoplastic resin incompatible with the polyester resin. Although their contents are not particularly limited, in the case of inorganic particles, 5 to 35% by mass, particularly preferably 8 to 25% by mass, is preferable with respect to the produced polyester. On the other hand, in the case of incorporating an incompatible thermoplastic resin, 5 to 35% by mass, particularly preferably 8 to 28% by mass, is preferable with respect to the polyester. Further, when using both inorganic particles and a thermoplastic resin incompatible with the polyester resin in combination, it is preferable from the viewpoints of film strength, stiffness, and film-forming stability that the total amount thereof be 40% by mass or less with respect to the polyester-based film.

[0016] The layer structure of the base polyester film in the present invention may be a single-layer structure or a laminated structure, but a laminated structure of X layer / Y layer / X layer is a preferred embodiment, in which the X layer contains inorganic particles and the Y layer contains fine voids. By disposing a layer containing inorganic particles in the X layer, which is the surface layer, it is possible to improve the slipperiness, i.e., handling property and concealability, of the film, and by containing fine voids only in the Y layer, which is the inner layer, it is possible to ensure the strength of the film surface while exhibiting the cushioning property of the film. Here, the method for forming the laminated structure is not particularly limited, but it is preferable from the viewpoints of stability during production and processing cost to perform it by coextrusion.

[0017] The content of the inorganic particles contained in the X layer is preferably 2.5 to 70.0% by mass, particularly preferably 4.0 to 60.0% by mass, and more preferably 6.0 to 50.0% by mass with respect to the polyester. The content of the incompatible thermoplastic resin contained in the Y layer is preferably 5 to 35% by mass, particularly preferably 8 to 28% by mass with respect to the polyester.

[0018] From the viewpoints of film strength, stiffness, and film-forming stability, the thickness ratio of each layer in the X layer / Y layer / X layer laminated structure is preferably in the range of 0.5 / 9 / 0.5 to 2 / 6 / 2, and more preferably in the range of 1 / 8 / 1 to 1.5 / 7 / 1.5.

[0019] The inorganic particles used are not particularly limited, but inorganic particles with an average particle size of 0.1 to 4.0 μm are preferred, and inorganic particles with an average particle size of 0.3 to 1.5 μm are particularly preferred. Specifically, white pigments such as titanium dioxide, barium sulfate, calcium carbonate, and zinc sulfide are preferred, and these may be mixed. Furthermore, inorganic particles commonly contained in films, such as silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, and calcium sulfate may also be used in combination.

[0020] Furthermore, the thermoplastic resin that is incompatible with the polyester resin is not particularly limited, but examples include polystyrene resin, polyethylene resin, polypropylene resin, polymethylpentene resin and other polyolefin resins, cyclic polyolefin resins, acrylic resins, phenoxy resins, polyphenylene oxide resins, and polycarbonate resins when mixed with polyethylene terephthalate resin. These thermoplastic resins may be mixed or modified. Naturally, they can also be used in combination with the inorganic particles mentioned above. It goes without saying that various whitening agents may also be added as needed.

[0021] Furthermore, the polyester film used in this invention has an apparent density of 0.3 to 1.3 g / cm³. 3It is preferable that the film is a polyester-based film containing fine cavities. Furthermore, a polyester-based film containing fine cavities having a cavity number density of 0.20 cavities / μm or more, preferably 0.25 cavities / μm or more, and more preferably 0.30 cavities / μm or more, in terms of achieving both cushioning properties and surface peel strength, is also preferable. As a result, the resulting polyester-based coated film has excellent print clarity and processing characteristics during printing. Here, the cavity number density (cavities / μm) is defined by the formula: number of cavities in the film thickness direction (cavities) / film thickness (μm). The upper limit of the cavity number density is preferably 0.80 cavities / μm, and more preferably 0.55 cavities / μm, in terms of cavity formation efficiency. Methods for adjusting the density to the above range include adjusting the amount, type, and viscosity of the incompatible thermoplastic resin, as well as changing the screw shape of the extruder or installing a static mixer in the molten resin flow path, but are not limited to these methods.

[0022] These polyester films containing microcavities are particularly useful because the microcavities within the film cause light scattering at the interface with the polyester matrix, resulting in significantly improved opacity and reducing the amount of inorganic particles that need to be added. Furthermore, by incorporating microcavities, the base film itself can be made lighter, making it easier to handle and resulting in significant economic benefits such as reduced raw material costs and transportation costs.

[0023] As a method for obtaining such a polyester film containing fine cavities, known methods already disclosed can be used, such as a method in which a thermoplastic resin incompatible with the polyester resin, as described above, is kneaded with a thermoplastic polyester resin that serves as a matrix, and a sheet in which the incompatible resin is dispersed in fine particles within the polyester resin is stretched in at least one axial direction to generate cavities around the incompatible resin fine particles.

[0024] Furthermore, the thickness of the obtained polyester film substrate is preferably 5 to 300 μm. More preferably, the thickness of the polyester film substrate is 20 to 300 μm, and even more preferably 40 to 250 μm.

[0025] The preferred whiteness when used in printing materials can be expressed by the color b value. A higher color b value indicates a stronger yellow tint, while a lower value indicates a stronger blue tint. The color b value corresponds well to visual inspection, and it is preferable that the color b value is 4.0 or less, and more preferably 3.0 or less. When the b value is 4.0 or less, the whiteness is good, and when used for labels, etc., it is preferable because it results in excellent clarity during printing and increases the product value. The lower limit of the color b value is preferably -5.0. When the b value is -5.0 or higher, the blue tint of the film does not become too strong, and it is preferable because it satisfies the resolution requirements in a good balance when used as a printing substrate.

[0026] (Explanation of characteristic values ​​in the present invention) The easily adhering coating layer in the present invention preferably contains a cationic antistatic agent having a nitrogen element, a polyester resin, and a polyurethane resin. By having the cationic antistatic agent component and the polyurethane resin component present on the surface of the easily adhering coating layer in suitable amounts and proportions, and by controlling the contact angle with water within a suitable range, electrostatic problems in the printing process are avoided, and good adhesion to various ink compositions is achieved. In particular, regarding adhesion to active energy ray curing ink layers such as ultraviolet (UV) curing inks, good adhesion is maintained without a decrease in adhesion to the ink layer even when stored in a high-temperature, high-humidity environment after printing.

[0027] Here, the amounts of the cationic antistatic agent component and the polyurethane resin component on the surface of the easy-to-adhere coating layer are evaluated by the peak areas of the ionized nitrogen element peak and the unionized nitrogen element peak in the N1s spectrum obtained by X-ray photoelectron spectroscopy (hereinafter referred to as ESCA). In ESCA, the element species and chemical state corresponding to the peak are identified from the peak position of the obtained measured spectrum. Furthermore, curve fitting can be performed on the elemental peaks to calculate the peak area. The easy-to-adhere coating layer in the present invention contains a cationic antistatic agent having the element nitrogen and a polyurethane resin. In the case of such an easy-to-adhere coating layer, the peaks of the ESCA N1s spectrum are exemplified as shown in Figure 1. The thin solid line in the figure represents the measured data of the N1s spectrum. Of the two peaks, (1) the peak around 402 eV of the curve represented by the dotted line in the figure is the ionized nitrogen element peak, and in the present invention, it can be determined to be derived from the cationic antistatic agent. Furthermore, in Figure (2), the peak around 400 eV in the curve represented by the dashed line is an unionized nitrogen element peak, which in this invention can be determined to originate from the polyurethane resin. Curve fitting is performed on the peaks of the spectra of all detected elements, including the N1s spectrum, and when the total peak area is set to 100 (at%), the area ratio in (1) is expressed as the nitrogen element ratio A (at%) derived from the cationic antistatic agent and is used as an indicator of the amount of the antistatic agent component present on the surface of the easily adhering coating layer. Similarly, the area ratio in (2) is expressed as the nitrogen element ratio B (at%) derived from the polyurethane resin and is used as an indicator of the amount of the polyurethane resin component present on the surface of the easily adhering coating layer.

[0028] Furthermore, regarding the easily adhering coating layer in the present invention, when the characteristic values ​​based on surface elemental distribution measurement by ESCA are in the following relationship (i)(ii), and the contact angle θH2O with water on the surface of the easily adhering coating layer is given by the following formula (iii), electrostatic interference in the printing process is avoided, and good adhesion to various ink compositions is maintained. In particular, regarding adhesion to active energy ray curing ink layers such as ultraviolet (UV) curing inks, good adhesion is maintained without a decrease in adhesion to the ink layer even when stored in a high-temperature, high-humidity environment after printing. (i) A(at%) > 0.4 (ii) 2.0 ≤ B / A ≤ 5.0 (iii) 50°≦θ H2O≦70°

[0029] According to the present invention, even when stored in a high-temperature, high-humidity environment after printing, it is possible to provide printed materials that maintain good adhesion without a decrease in adhesion between the ink layer and the easily adhesive coating layer. The storage test conditions in the high-temperature, high-humidity environment in the present invention were set to a temperature of 80°C and a humidity of 90%RH for 3 days, assuming use in labels for industrial electronic components or as food labels in humid environments such as Southeast Asia. Furthermore, in the adhesion evaluation described later, it is preferable that the remaining area of ​​the printed layer before and after storage under the above storage test conditions is 90% or more of the total area, which is a range in which good adhesion and adhesion are maintained without a decrease in adhesiveness or adhesion.

[0030] This invention explains the principle of antistatic performance and its correlation with adhesion to ink when using ionic antistatic agents, including cationic antistatic agents, as described in this invention. When using ionic antistatic agents to exhibit antistatic properties on a substrate surface, it is preferable to form a water network on the substrate surface that facilitates the flow of static electricity. Ionic antistatic agents, by being present on the substrate surface, have the effect of attracting moisture from the air. Therefore, the greater the amount of ionic antistatic agent present on the substrate surface, the easier it is to attract moisture from the air and to form a water network, thus making it easier to exhibit antistatic properties. However, on the other hand, an increase in the amount of ionic antistatic agent on the substrate surface relatively reduces the amount of resin present. In other words, in this invention, the amount of polyurethane resin, which is generally considered to be related to adhesion to ink, decreases, and there is a risk that adhesion will decrease. Therefore, it is preferable to control the amounts of ionic antistatic agent and resin (especially polyurethane resin) on the surface of the easily adhesive coating layer to a suitable range. Even when the amount of ionic antistatic agent on the surface of the easily adhesive coating layer is small, it is preferable to control the contact angle of the surface of the easily adhesive coating layer with respect to water in order to form a water network. By controlling the contact angle of the easily adhering coating surface to a suitable range, moisture attracted by the antistatic agent on the surface of the easily adhering coating can spread wetting even to areas where the antistatic agent is absent. In other words, controlling the contact angle of the easily adhering coating surface can assist in the formation of a water network. Therefore, good antistatic properties can be obtained even with a smaller amount of antistatic agent. By assisting the formation of a water network, excessive water wetting is suppressed, resulting in a favorable contact state between the ink and the polyurethane resin component on the surface of the easily adhering coating. In addition, by controlling the contact angle of the easily adhering coating surface to a suitable range, the affinity of the printed material with various inks is increased, improving ink adhesion and wetting spread. Furthermore, when stored in a high-temperature, high-humidity environment, it is possible to suppress the deterioration of the easily adhering coating due to moisture that has permeated the ink layer, thereby maintaining adhesion.

[0031] A(at%) is preferably greater than 0.4. By controlling it within this range, it becomes possible to attract moisture from the air to the coating surface. By controlling the contact angle with water on the surface of the easily adhesive coating layer (described later) within a suitable range, good antistatic properties can be obtained, and electrostatic problems in the printing process can be avoided. A(at%) is more preferably 0.5at% or more, and even more preferably 0.6at% or more. However, if A(at%) is too large, it becomes difficult to satisfy the following preferred range for B / A, so it is preferably 5at% or less, more preferably 3at% or less, and even more preferably 2at% or less.

[0032] The B / A ratio is preferably between 2.0 and 5.0. By controlling the B / A ratio within this range and controlling the contact angle of the coating surface with respect to water within a suitable range, both antistatic properties and adhesion to ink can be achieved. In addition, even when printed materials are stored in high-temperature and high-humidity environments, it is possible to suppress coating deterioration and maintain good adhesion. The lower limit of the B / A ratio is more preferably 3.0 or higher. On the other hand, the upper limit of the B / A ratio is more preferably 4.0 or lower.

[0033] The contact angle of the coating surface with respect to water is preferably in the range of 50° to 70°. The lower limit of the contact angle of the coating surface with respect to water is more preferably 60° or higher. On the other hand, the upper limit of the contact angle of the coating surface with respect to water is more preferably 68° or lower. By controlling it within the range of 50° to 70°, a good assist effect on the formation of a water network on the coating surface can be obtained. Furthermore, as a printed material, the affinity with various inks is increased, improving adhesion and wetting spread with the ink. In addition, when stored in a high-temperature, high-humidity environment, it becomes possible to suppress the deterioration of the easily adhesive coating layer due to moisture that has permeated the ink layer, and thus maintain adhesion.

[0034] (Easy-to-adhere coating layer) In the present invention, the easily adhesive polyester film is preferably provided with an easily adhesive coating layer on at least one side, comprising a cation-based antistatic agent containing nitrogen, a polyester resin, and a polyurethane resin, in order to achieve both antistatic properties and good adhesion to inks and toners, and particularly good adhesion to UV-curable inks during high-speed printing. The easily adhesive coating layer may be provided on both sides of the polyester film, or it may be provided on only one side of the polyester film, with a different type of resin coating layer on the other side.

[0035] The following provides a detailed explanation of the various compositions of the easily adhering coating layers. (Cationic antistatic agent) Cationic antistatic agents include polyethyleneimine, polydimethyldiallylammonium salt, polyalkylene polyamine dicyanodiamide ammonium condensate, polyvinylpyridium halide, (meth)acrylate alkyl quaternary ammonium salt, (meth)acrylamide alkyl quaternary ammonium salt, ω-chloro-poly(oxyethylene-polymethylene-alkyl quaternary ammonium salt), polyvinylbenzyltrimethylammonium salt, polystyrene-based cationic polymers, poly(meth)acrylic-based cationic polymers (methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate, trimethylaminoethyl methacrylate chloride, etc.), polyvinylpyridine-based polymers, cyclic integral polymers, linear integral polymers, polymers of aromatic vinyl monomers having two or more quaternary ammonium ion groups in a pendant shape, and polymers having pyrrolidium rings in the main chain. These polymers may be homopolymers or copolymers. Known copolymerizable monomers can be used to produce these polymers. In controlling the amount of antistatic agent components present on the surface of the easily adhering coating layer, it is preferable that the antistatic agent has a linear alkyl group, and more preferably that it has a linear alkyl group and a quaternary ammonium base.

[0036] In the present invention, it is preferable that the antistatic agent is present on the surface of the easily adhering coating layer.

[0037] Therefore, in an antistatic agent having a linear alkyl group and a quaternary ammonium base, the number of carbon atoms in the alkyl chain is preferably 10 to 20, more preferably 12 to 19, and particularly preferably 14 to 18. In order to control the nitrogen element ratio derived from a cationic antistatic agent having nitrogen elements, based on surface elemental distribution measurement by ESCA, it is preferable to bleed out the antistatic agent from the surface of the easily adhering coating layer, and considering the interactions between the molecules and the ease of bleeding out due to molecular length, it is preferable to set it within the above range.

[0038] Furthermore, in the molecular structure of a cationic antistatic agent containing a nitrogen element, at least one amide bond or urethane bond may be included between the linear alkyl chain and the quaternary ammonium base.

[0039] In the above-mentioned antistatic agent, the counterion of the quaternary ammonium base is not particularly limited as long as it is an anionic compound, but preferably it can be appropriately selected from halogen ions, mono- or polyhalogenated alkyl ions, nitrate ions, sulfate ions, alkyl sulfate ions, sulfonate ions, or alkyl sulfonate ions, but preferably chloryl ions, metasulfonic acid ions, ethanesulfonic acid ions, or nitrate ions are selected.

[0040] (Polyester resin) The polyester resin used to form the easily adhering coating layer in the present invention may be linear, but more preferably it is a polyester resin composed of a dicarboxylic acid and a diol having a branched structure. The dicarboxylic acid referred to here may be terephthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid as its main component, as well as aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid. Furthermore, branched glycols are diols having branched alkyl groups, and examples include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2-butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, and 2,2-di-n-hexyl-1,3-propanediol.

[0041] The dicarboxylic acid used as a component of the polyester resin is preferably terephthalic acid or isophthalic acid. In addition to the dicarboxylic acid, it is preferable to copolymerize 5-sulfoisophthalic acid or the like in the range of 1 to 10 mol% in order to impart water dispersibility to the copolymerized polyester resin. Examples include sulfoterephthalic acid, 5-sulfoisophthalic acid, and 5-sodium sulfoisophthalic acid. A polyester resin containing a dicarboxylic acid having a naphthalene skeleton may be used, but in order to suppress a decrease in adhesion to curable inks, the quantitative proportion of the dicarboxylic acid is preferably 5 mol% or less of the total carboxylic acid component, and it may not be necessary to use it.

[0042] The above-mentioned polyester resin may contain triols or tricarboxylic acids as constituent components, to the extent that the properties of the polyester resin are not impaired.

[0043] The above polyester resin may contain polar groups other than carboxyl groups. Examples include metal sulfonic acid bases and phosphate groups, and these may be present in one or more types. A method for introducing metal sulfonic acid bases is to use a dicarboxylic acid or glycol containing a metal sulfonic acid base, such as a metal salt of 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5-[4-sulfophenoxy]isophthalic acid, or a metal salt of 2-sulfo-1,4-butanediol, 2,5-dimethyl-3-sulfo-2,5-hexanediol, etc., in an amount of 10 mol% or less, preferably 7 mol% or less, and more preferably 5 mol% or less, of the total amount of the polycarboxylic acid component or polyol component. An amount of 10 mol% or less is preferable because it provides good hydrolysis resistance to the resin itself and water resistance to the coating film.

[0044] (Polyurethane resin) In the present invention, it is preferable to have an antistatic agent on the surface of the easily adhering coating layer, so that the characteristic values ​​based on surface elemental distribution measurement by ESCA satisfy a suitable relationship, and the contact angle of the easily adhering coating layer surface with respect to water satisfies a suitable range. For this reason, it is preferable to mainly control the polarity of the polyurethane resin.

[0045] One method for controlling the polarity of polyurethane resins is to control the structure of the polyol component used in the synthesis and polymerization of the polyurethane resin. Generally, the polarity of ester skeletons and carbonate skeletons tends to be lower than that of ether skeletons. When the nitrogen element ratio derived from cationic antistatic agents, based on surface elemental distribution measurements by ESCA, falls below a suitable range, it is preferable to use a polyurethane resin in which the polyol component used in the synthesis and polymerization of the polyurethane resin has an ester skeleton or a carbonate skeleton, with the aim of reducing the interaction between the polyurethane resin and the cationic antistatic agent and ensuring that the antistatic agent is present on the surface of the easily adhering coating layer. Using a polyurethane resin with a carbonate skeleton is particularly preferable.

[0046] Examples of ether-backed polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol.

[0047] Examples of ester-skeleton polyols include polyhydric 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) Examples include 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, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamines, lactonediols, etc.

[0048] The carbonate backbone polyol preferably contains an aliphatic polycarbonate polyol that has excellent heat resistance and hydrolysis resistance. 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 used to synthesize and polymerize polyurethane resins having a polycarbonate structure in 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, and dipropylene glycol with carbonates such as dimethyl carbonate, ethylene carbonate, and phosgene.

[0049] Another method for controlling the polarity of polyurethane resins is to control the number-average molecular weight of the polyol component used in the synthesis and polymerization of the polyurethane resin. Generally, when the number-average molecular weight of the polyol component used in the synthesis and polymerization of polyurethane resin is large, the polarity of the polyurethane resin tends to be low, while when the number-average molecular weight of the polyol component is small, the polarity of the polyurethane resin tends to be high. When the contact angle of the surface of the easily adhesive coating layer to water is not within a suitable range, it is preferable to increase the number-average molecular weight of the polyol component to lower the polarity of the polyurethane resin. Conversely, when the contact angle of the surface of the easily adhesive coating layer to water exceeds a suitable range, it is preferable to decrease the number-average molecular weight of the polyol component to increase the polarity of the polyurethane resin. As an example of the number-average molecular weight, when the polyol used in the synthesis and polymerization of polyurethane resin is an ester-backed polyol, the number-average amount is preferably 1000 to 2400. More preferably, it is 1200 to 2200, and particularly preferably 1400 to 2200. Furthermore, in the case of carbonate-backed polyols, the number average amount is preferably 500 to 1800, more preferably 600 to 1600, and particularly preferably 700 to 1400.

[0050] One method for controlling the polarity of polyurethane resin is to control the amount of urethane groups in the molecule. Generally, when there are many urethane groups in the molecule, the polarity of the polyurethane resin increases, and the amount of polyurethane resin component on the surface of the easily adhesive coating layer tends to increase. On the other hand, when there are few urethane groups in the molecule, the polarity of the polyurethane resin decreases, and the amount of polyurethane resin component on the surface of the easily adhesive coating layer tends to decrease. Therefore, by controlling the amount of urethane groups in the molecule, the amount of antistatic agent component, the amount of polyurethane resin component, and the contact angle with water on the surface of the easily adhesive coating layer change in parallel. As an example of setting the characteristic values ​​based on surface elemental distribution measurement by ESCA in the present invention, and the contact angle with water on the surface of the easily adhesive coating layer to a suitable range, the amount of urethane groups in the molecule (number average molecular weight of isocyanate component used in the synthesis and polymerization of polyurethane resin / number average molecular weight of polyurethane resin) is preferably 26 to 38. More preferably 26 to 36.

[0051] Known methods can be applied to produce the polyurethane resin in the present invention. For example, a prepolymer having isocyanate at the ends can be synthesized from a polyol and an excess of polyisocyanate, and then this prepolymer can be reacted with a chain extender or crosslinking agent to increase its molecular weight.

[0052] Examples of polyisocyanates used in the synthesis and polymerization of polyurethane resins in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate and 1,3-bis(isocyanate-methyl)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. When using the aforementioned aromatic aliphatic diisocyanates, alicyclic diisocyanates, or aliphatic diisocyanates, there is no problem of yellowing, which is preferable. Furthermore, the coating film does not become too rigid, the stress due to thermal shrinkage of the polyester film substrate can be relieved, and there is no problem of cohesive failure of the easily adhering coating layer, which is preferable.

[0053] Examples of chain extenders used in the synthesis and polymerization of polyurethane resins in the present invention include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol; diamines such as ethylenediamine, hexamethylenediamine, and piperazine; amino alcohols such as monoethanolamine and diethanolamine; thiodiglycols such as thiodiethylene glycol; or water.

[0054] In the present invention, the easily adhering coating layer is preferably provided using an aqueous coating solution by the in-line coating method described later. Therefore, it is desirable that the polyurethane resin in the present invention be water-soluble or water-dispersible. The above-mentioned "water-soluble or water-dispersible" means that it is dispersed in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

[0055] To impart water dispersibility to a polyurethane resin, a sulfonic acid (salt) group or a carboxylic acid (salt) group can be introduced (copolymerized) into the urethane molecular backbone. A polyurethane resin into which a nonionic group such as a polyoxyalkylene group has been introduced is particularly preferable because it can minimize the interaction between the polyurethane resin and a cationic antistatic agent.

[0056] The method for introducing the above nonionic group can be appropriately selected from known methods. For example, one method involves replacing a portion of the polymer polyol with a diol containing a polyoxyethylene group, or one involves pre-reacting some of the isocyanate groups in the nurate of the diisocyanate with methoxypolyethylene glycol, and then reacting it with the polymer polyol.

[0057] In order to introduce a carboxylic acid (salt) group into the polyurethane resin in the present invention, for example, a polyol compound having a carboxylic acid group, such as dimethylolpropanoic 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.

[0058] When a polyol compound having a carboxylic acid (salt) group is used as a copolymer component to impart water dispersibility, the molar ratio of the polyol compound having a carboxylic acid (salt) group in the polyurethane resin is preferably 3 to 25 mol%, more preferably 3 to 18 mol%, and particularly preferably in the range of 3 to 15 mol%, when the total polyisocyanate component of the polyurethane resin is considered to be 100 mol%. By controlling it to the above range, water dispersibility is ensured, and interaction with coexisting cationic antistatic agent components is suppressed, allowing the antistatic agent to exist on the surface of the easily adhering coating layer.

[0059] The polyurethane resin in this invention may be a self-crosslinkable polypolyurethane resin to which blocked isocyanates are bonded to the ends in order to improve rigidity.

[0060] The polyurethane resin in the present invention may have a branched structure.

[0061] To form a branched structure in a polyurethane resin, for example, a method may be preferably employed in which the polycarbonate polyol component, polyisocyanate, and chain extender are reacted at an appropriate temperature and time, and then a compound having three or more functional hydroxyl groups or isocyanate groups is added to further allow the reaction to proceed.

[0062] Specific examples of compounds having three or more functional hydroxyl groups include caprolactone triol, glycerol, trimethylolpropane, butanetriol, hexanetriol, 1,2,3-hexanetriol, 1,2,3-pentanetriol, 1,3,4-hexanetriol, 1,3,4-pentanetriol, 1,3,5-hexanetriol, 1,3,5-pentanetriol, and polyethertriol. Examples of the aforementioned polyethertriol include compounds obtained by addition polymerization of one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide, glycidyl ether, methylglycidyl ether, t-butylglycidyl ether, and phenylglycidyl ether, using one or more compounds having three active hydrogen atoms, such as glycerin, alcohols like trimethylolpropane, and diethylenetriamine, as initiators.

[0063] Specific examples of compounds having three or more functional isocyanate groups include polyisocyanate compounds having at least three isocyanate (NCO) groups in one molecule. In the present invention, examples of isocyanate compounds having three or more functional groups include burettes, nurates, and adducts obtained by modifying isocyanate monomers such as aromatic diisocyanates, aliphatic diisocyanates, aromatic aliphatic diisocyanates, and alicyclic diisocyanates, which have two isocyanate groups. Examples of aromatic diisocyanates include 1,3-phenylenediisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylenediisocyanate, 4,4'-diphenylmethanediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4'-toluidinediisocyanate, dianisidinediisocyanate, and 4,4'-diphenyl ether diisocyanate. Examples of aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate. Examples of aromatic aliphatic diisocyanates include xylylene diisocyanate, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate. Alicyclic diisocyanates include, for example, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI or isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,4-bis(isocyanate methyl)cyclohexane.A burette compound is a self-condensate having a burette bond formed by the self-condensation of isocyanate monomers, such as the burette compound of hexamethylene diisocyanate. A nurate compound is a trimer of an isocyanate monomer, such as the trimer of hexamethylene diisocyanate, the trimer of isophorone diisocyanate, and the trimer of tolylene diisocyanate. An adduct compound is an isocyanate compound with three or more functions, formed by reacting the above-mentioned isocyanate monomer with a low-molecular-weight active hydrogen-containing compound with three or more functions, such as a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate, a compound obtained by reacting trimethylolpropane with tolylene diisocyanate, a compound obtained by reacting trimethylolpropane with xylylene diisocyanate, and a compound obtained by reacting trimethylolpropane with isophorone diisocyanate.

[0064] Chain extenders having three or more functional groups include trimethylolpropane, as described above, and alcohols having three or more hydroxyl groups, such as pentaerythritol.

[0065] (ratio) In the present invention, it is preferable that an antistatic agent be present on the surface of the easily adhering coating layer, that the characteristic values ​​based on surface elemental distribution measurement by ESCA satisfy a suitable relationship, and that the contact angle of the surface of the easily adhering coating layer with respect to water satisfies a suitable range. Therefore, it is preferable to control the polarity of the easily adhering coating layer mainly by controlling the polarity of the polypolyurethane resin, and further by adjusting the solid content ratio of each component to the total solid content of the cationic antistatic agent, polyester resin, and polyurethane resin.

[0066] When the total solid content of the cationic antistatic agent, polyester resin, and polyurethane resin in the coating solution is 100% by mass, the content (by mass) of the cationic antistatic agent is preferably 3.5 to 7.0, and more preferably 4.0 to 5.5. By setting it within this range, the nitrogen element ratio derived from the cationic antistatic agent, and the nitrogen element ratio derived from the polyurethane resin / nitrogen element ratio derived from the cationic antistatic agent, based on surface element distribution measurement by ESCA, can be controlled to a suitable range.

[0067] When the total solid content of the cationic antistatic agent, polyester resin, and polyurethane resin in the coating solution is 100% by mass, the polyester resin content (by mass) is preferably 25 to 80%, more preferably 30 to 80%, and particularly preferably 35 to 80%. By setting it within this range, the adhesion between the easily adhering coating layer and the polyester film substrate is ensured, and the amount of polar groups in the polyester resin, such as carboxyl groups, sulfonic acid metal bases, and phosphate groups, which can interact with the coexisting cationic antistatic agent components, is controlled, and the nitrogen element ratio derived from the cationic antistatic agent containing nitrogen elements, based on surface elemental distribution measurement by ESCA, can be controlled within a suitable range.

[0068] When the total solid content of the cationic antistatic agent, polyester resin, and polyurethane resin in the coating solution is taken as 100% by mass, the polyurethane resin content (by mass) is preferably 15 to 65, and more preferably 20 to 55. If the polyurethane resin content is low, the proportion of polyester resin becomes relatively high, and the amount of polar groups such as carboxyl groups, sulfonic acid metal bases, and phosphate groups in the polyester resin in the easily adhering coating layer increases. If the polyurethane resin content is high, the polarity of the easily adhering coating layer decreases. While the polyurethane component on the surface of the easily adhering coating layer increases, the polarity of the easily adhering coating layer is low, so the cationic antistatic agent tends to be present on the surface of the easily adhering coating layer. In other words, the cationic antistatic agent component on the surface of the easily adhering coating layer also increases. Taking these factors into consideration, by setting the polyurethane resin content (by mass) within the above range, the nitrogen element ratio derived from the cationic antistatic agent containing nitrogen elements, and the ratio of nitrogen elements derived from polyurethane resin to nitrogen elements derived from the cationic antistatic agent, based on surface element distribution measurement by ESCA, can be controlled to a suitable range.

[0069] (Additives) In the easily adhering coating layer of the present invention, known additives such as surfactants, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic particles, nucleating agents, etc., may be added, provided that they do not impair the effects of the present invention.

[0070] To reduce the glossiness of the easily adhering coating layer, inert particles may be included in the easily adhering coating layer.

[0071] Examples of the aforementioned inert particles include inorganic particles such as titanium dioxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, and calcium fluoride, as well as organic polymer particles such as polystyrene, polyacrylic, melamine, benzoguanamine, and silicone resins. These may be used individually or in combination of two or more types.

[0072] The average particle size of the inert particles is preferably 0.1 to 2.4 μm, and more preferably 0.3 to 2.0 μm. An average particle size of 0.1 μm or more is preferable because it prevents the glossiness of the film surface from becoming too high. Conversely, an average particle size of 2.4 μm or less is preferable because it prevents the particles from easily falling off the easily adhesive coating layer, thus preventing powder shedding.

[0073] The amount of inert particles can be added within a range that does not hinder the effects of the present invention. However, in order to prevent the particles from falling off the easily adhesive coating layer and causing powder fallout, the particle content is preferably 0 to 70.0% by mass, preferably 0 to 60.0% by mass, and more preferably 0 to 55.0% by mass, relative to the total solid content of the easily adhesive coating layer.

[0074] The shape of the particles is not particularly limited as long as it satisfies the objectives of the present invention; spherical particles and irregularly shaped non-spherical particles can be used. The particle size of irregularly shaped particles can be calculated as the equivalent diameter of a circle.

[0075] To increase the glossiness of the easily adhering coating layer, it is best to avoid including particles in the easily adhering coating layer.

[0076] (Method for manufacturing polyester film) The method for manufacturing the polyester film in this invention is arbitrary and not particularly limited, but for example, it can be manufactured as follows.

[0077] After thoroughly vacuum-drying the film raw material, it is melted in an extruder and extruded into a sheet form from a T-die onto a rotating cooling metal roll while applying static electricity to the sheet, thereby obtaining an unstretched film.

[0078] In this process, rather than adding the white pigment and other additives in powder form to the extruder and mixing them, it is preferable to create masterbatch polymers in which the white pigment and other additives are separately and at high concentrations in the polyester resin beforehand, and then blend and dilute them with the polyester resin, from the viewpoint of uniform mixing. It is preferable to use a twin-screw extruder to further ensure thorough and uniform mixing of the various film raw materials. Furthermore, when polymerizing the polyester to improve electrostatic adhesion, it is preferable to add alkaline earth metal salts and / or alkali metal salts and phosphoric acid or a salt thereof. Adding phosphoric acid or a salt thereof also has the effect of improving the color tone (especially the b value).

[0079] In the present invention, the polyester film substrate may be a single-layer structure or a laminated structure. In the case of a laminated structure, there is an advantage that the composition of the surface layer and the core layer can be designed in various ways according to the required function. When the polyester film substrate is a laminated structure, it is most preferable to employ a co-extrusion method in which the resins of the X layer and the Y layer are supplied to separate extruders, and then laminated in a molten state to form a two-layer structure of X layer / Y layer, or a three-layer structure of X layer / Y layer / X layer, and then extruded from the same die.

[0080] The resulting unstretched film is then subjected to biaxial orientation processing by methods such as stretching between rolls at different speeds (roll stretching), stretching by gripping and spreading it with clips (tenter stretching), or stretching by expanding it with air pressure (inflation stretching).

[0081] The conditions for stretching and oriented an unstretched film are closely related to the film's physical properties. Below, we will explain the stretching and orientation conditions using the most common sequential biaxial stretching method, particularly the method of stretching an unstretched sheet longitudinally and then in the widthwise direction, as an example.

[0082] First, in the initial longitudinal stretching process, the film is stretched between two or more rolls with different peripheral speeds. The heating method at this stage may be a method using heated rolls, a non-contact heating method, or a combination of both. Next, the uniaxially oriented film is introduced into a tenter and stretched 2.5 to 5 times in the width direction at a temperature below the melting point Tm of polyester (Tm -10°C).

[0083] The biaxially oriented film obtained in this manner is subjected to heat treatment as necessary. The heat treatment is preferably carried out in a tenter, and the heat treatment temperature is preferably in the range of the melting point of polyester (Tm) - 50 (°C) to Tm (°C).

[0084] (Void-containing PET manufacturing method) In the present invention, the polyester film substrate may be prepared by dispersing a thermoplastic resin incompatible with the polyester resin in the polyester resin during the process of melting and extruding the film raw material. The polyester film substrate in the present invention may also preferably be a white polyester film substrate. In the experimental examples of the present invention, the polyester resin and the thermoplastic resin incompatible with the polyester resin were supplied in pellet form, but the invention is not limited to this.

[0085] The raw materials fed into the extruder for melt molding into a film are prepared by mixing these resins into pellets according to the desired composition. In the present invention, a preferred method for preventing segregation of the polyester film substrate is to pre-mix and pelletize a portion or all of the raw resins to form a masterbatch pellet. In the experimental examples of the present invention, this method was used, but the invention is not particularly limited as long as it does not hinder the effects of the present invention.

[0086] Furthermore, in the extrusion of these immiscible resin mixtures, even after mixing and finely dispersing them in a molten state, the resins have a tendency to re-aggregate due to an attempt to reduce their interfacial energy. This phenomenon occurs when extruding unstretched films, causing the cavity-forming agent to become coarsely dispersed and hindering the development of desired physical properties.

[0087] To prevent this, when forming the film in the present invention, it is preferable to use a twin-screw extruder with a higher mixing efficiency to pre-disperse the cavity-forming agent. If this is difficult, it is also preferable to supply the raw resin from the extruder to the feed block or die via a static mixer as an auxiliary means. A static mixer or an orifice can be used as the static mixer here. However, when these methods are adopted, it is preferable to prevent the accumulation of heat-degraded resin in the melt line.

[0088] Furthermore, in the case of thermoplastic resins that are incompatible with polyester once dispersed in polyester resin as fine particles, re-aggregation of the incompatible resins tends to progress over time under low-shear melting conditions. Therefore, reducing the residence time in the melt line from the extruder to the die is a fundamental solution. In the present invention, it is preferable to set the residence time in the melt line to 30 minutes or less, and more preferably to 15 minutes or less.

[0089] The conditions for stretching and oriented the unstretched film obtained as described above are closely related to the physical properties of the film. Below, we will explain the stretching and orientation conditions using the most common sequential biaxial stretching method, in particular the method of stretching the unstretched film in the longitudinal direction and then in the width direction, as an example.

[0090] In the longitudinal stretching process, the film is stretched 2.5 to 5.0 times in the longitudinal direction using a roll heated to 80 to 120°C to obtain a uniaxially oriented film. The heating method may be either using a heated roll or a non-contact heating method, or a combination of both. Next, the uniaxially oriented film is introduced into a tenter and stretched 2.5 to 5 times in the width direction at a temperature of (Tm-10°C) or lower. Here, Tm refers to the melting point of polyester.

[0091] Furthermore, the biaxially oriented film described above is subjected to heat treatment as necessary. The heat treatment is preferably carried out in a tenter, and preferably in the range of (Tm-60℃) to Tm.

[0092] (Preparation when using recycled polyester raw materials) The polyester resin in this invention may include polyester resin recycled from PET bottles. The polyester used in PET bottles has its crystallinity controlled to improve bottle moldability and appearance, and as a result, it may contain ester units derived from isophthalic acid components in amounts of 0.5 mol% to 10.0 mol% of the total ester units in the polyester resin and any diol components such as ethylene glycol or diethylene glycol. In addition, polyester with increased intrinsic viscosity, achieved by further solid-phase polymerization after liquid-phase polymerization, may be used. Recycled polyester resin pellets from PET bottles are usually obtained by washing, crushing, heating and melting PET bottles to re-pelletize them, but it is also acceptable to use those that have been further solid-phase polymerized to increase their intrinsic viscosity. The intrinsic viscosity of the recycled polyester resin from PET bottles is preferably in the range of 0.60 to 0.75 dl / g. An intrinsic viscosity of 0.60 dl / g or higher is preferable because it makes the resulting film less likely to break, thus facilitating stable film production. On the other hand, an intrinsic viscosity of 0.75 dl / g or less is preferable because it prevents the filtration pressure of the molten fluid from rising too much, making it easier to operate the film manufacturing process stably. Generally, when polyethylene terephthalate resin is solid-phase polymerized, the amount of oligomers contained in the resin, especially PET cyclic trimers which are the most abundant, is less than that of liquid-phase polymerized resin. The upper limit of cyclic trimer oligomers contained in recycled polyester resin made from PET bottles is preferably 0.7% by mass, more preferably 0.5% by mass, and more preferably 0.4% by mass.

[0093] The lower limit of the content of recycled polyester resin from PET bottles in the cavity-containing polyester film is preferably 25% by mass, more preferably 30% by mass, and even more preferably 50% by mass. A content of 25% by mass or more is preferable because it reduces the amount of oligomers contained in the cavity-containing polyester film, thereby suppressing the precipitation of oligomers. Furthermore, in terms of utilizing recycled resin, a higher content is preferable in terms of contributing to the reduction of environmental impact. The upper limit of the content of recycled polyester resin from PET bottles is preferably 90% by mass, and more preferably 85% by mass.

[0094] The easy-adhesion coating layer can be applied after the film is manufactured or during the manufacturing process. In particular, from the viewpoint of productivity, it is preferable to apply the coating solution to at least one side of the PET film after it has been unstretched or uniaxially stretched, thereby forming the easy-adhesion coating layer.

[0095] Any known method can be used to apply this coating solution to the 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, and the like. These methods can be used individually or in combination.

[0096] Regarding the drying conditions after coating, in order to bleed out the cationic antistatic agent component from the surface of the easily adhering coating layer and for the characteristic values ​​based on surface elemental distribution measurement by ESCA to satisfy a favorable relationship, the temperature should be 80°C to 150°C, more preferably 90°C to 140°C. Particularly preferably, the range of 100°C to 130°C is preferred. However, by increasing the drying time, it may be possible to bleed out the cationic antistatic agent component from the surface of the easily adhering coating layer even at relatively low temperatures, and the characteristic values ​​based on surface elemental distribution measurement by ESCA may satisfy a favorable relationship, so the conditions are not limited to the above.

[0097] In the present invention, the thickness of the easily adhering coating layer is preferably in the range of 50 to 900 nm, more preferably in the range of 70 to 800 nm, even more preferably in the range of 100 to 600 nm, and particularly preferably in the range of 200 to 500 nm. As the thickness of the easily adhering coating layer increases, the amount of cationic antistatic agent components interposed per volume of the easily adhering coating layer increases. In other words, these components bleed out to the surface of the easily adhering coating layer, resulting in a large amount of cationic antistatic agent components being present on the surface of the easily adhering coating layer. On the other hand, as the thickness of the easily adhering coating layer decreases, the amount of cationic antistatic agent components interposed per volume of the easily adhering coating layer decreases. In other words, the amount of cationic antistatic agent components present on the surface of the easily adhering coating layer also decreases. Therefore, by controlling the thickness of the easily adhering coating layer within the above range, the nitrogen element ratio derived from the cationic antistatic agent and the nitrogen element ratio derived from the polyurethane resin / nitrogen element ratio derived from the cationic antistatic agent can be controlled to a suitable range for surface elemental distribution measurement by ESCA.

[0098] (UV-curing ink) In this invention, UV-curable ink is a general term for inks that cure with ultraviolet light. The composition includes pigments (dyes), oligomers and monomers, photopolymerization initiators and accelerators, auxiliary agents, etc. The oligomers and monomers act as fluid components within the ink, and after being spread to the substrate, they cure under an ultraviolet lamp due to radicals generated from the photopolymerization initiator. The proportion of oligomers and monomer species varies depending on the printing method described later. Basically, it is preferable that the ink does not contain solvents except for viscosity adjustment, or if it does, it should be no more than about 10% by mass.

[0099] (Solvent-based ink) In this invention, solvent-based inks are a general term for inks that harden by evaporation and drying. The ink's composition includes pigments (dyes), resin components, diluent solvents, auxiliary agents, etc. After printing, the solvent rapidly evaporates, leaving the resin and pigment components fixed to the printed surface. Because of its extremely fast drying speed, it is suitable for high-speed, high-volume printing.

[0100] (Oxidation polymerization type ink) The oxidative polymerization ink in this invention is mainly composed of a drying oil that polymerizes and hardens with oxygen in the air, and also contains pigments (dyes), polymerization accelerators, auxiliary agents, etc. The drying oil acts as a fluid component, and the viscosity is adjusted according to the printing method. Recently, there are also composite types that contain both UV-curing components and drying oils. The solvents mentioned above mainly refer to organic solvents, including hydrocarbons such as hexane and heptane, esters such as ethyl acetate and ethyl acetate, and ketones such as acetone and MEK, and these can be used individually, in mixtures thereof, or in mixtures with alcohols. Polymerizable and hardening monomers, oligomers, and oils are not included in organic solvents. Printing methods that use these include flexographic printing, screen printing, and offset printing. The viscosity of the ink is set higher for the latter.

[0101] (Thermal transfer ink) The thermal transfer ink in this invention is a heat-meltable pigment ink used in a thermal transfer printing method in which ink coated on an ink ribbon is melted by heat and transferred to paper for printing. The ink's composition includes colorants such as pigments and dyes, binders such as waxes and thermoplastic resins, and various additives such as softeners and dispersants. Resin-type and wax-type inks are used in thermal transfer printing. Among these, the resin-type is preferred due to its superior weather resistance. Applications include monochrome document output in word processors, tape writers, and barcode printers. It is also used in some color printers and video printers by using color ribbons.

[0102] (LBP Toner) In this invention, LBP toner refers to a coloring powder used in laser printers and copiers, and is a compound of electrostatically charged fine particles (polymer resin), wax, pigment, etc. For color printing, four colors are used: blue-green, magenta, yellow, and black. LBP refers to a page printer that charges the drum with laser light and adheres the toner using static electricity.

[0103] The evaluation method used in this invention is described below. (1) Nitrogen elements in the surface region (N and N + ) Measurement of ratio Surface composition was measured using ESCA. The instrument used was K-Alpha + (Thermo Fisher Scientific) was used. Details of the measurement conditions are shown below. Background removal was performed using the Shirley method during analysis. The surface composition ratio was calculated as the average of the results from three or more measurements, and N(N) + The isoionized nitrogen element (N) and the unionized nitrogen element (CN) were calculated by peak separation of the N1s spectrum. Here, N(N + The peak around 402 eV in the N1s spectrum represents isoionized nitrogen, while the peak around 400 eV represents unionized nitrogen (N, e.g., CN). • Measurement conditions Excitation X-rays: Monochromatized Al Kα rays X-ray output: 12 kV, 6 mA Photoelectron escape angle: 90° Spot size: 400 μmφ Pass energy: 50 eV Step: 0.1eV Figure 1 is a graph showing the analysis results of the N1s spectrum in the surface region of a substrate with an easily adhering coating layer in Experimental Example 1. The thin solid line represents the measured data of the N1s spectrum. The peaks of the obtained measured spectrum were separated into multiple peaks, and the binding species corresponding to each peak was identified from the position and shape of each peak. Furthermore, curve fitting was performed on the peaks derived from each binding species, and the peak area was calculated. N(N + The peak area for isionized nitrogen (CN) was defined as A (at%), and the peak area for non-ionized nitrogen (CN) was defined as B (at%).

[0104] (2) Measurement of contact angle with water The substrate having an easily adherable coating layer was left standing in an atmosphere of 23°C and 65% RH for 24 hours, and then, in that atmosphere, using a contact angle meter (CA-X manufactured by Kyowa Interface Science Co., Ltd.), the contact angle between the coated layer surface of the sample and water was measured using distilled water stored under the same conditions. The measurement was carried out 10 times, and the average value thereof was taken as the contact angle data.

[0105] (3) Surface resistivity of the easily adherable coating layer After the substrate having an easily adherable coating layer was left standing in an atmosphere of 23°C and 65% RH for 24 hours, in that atmosphere, using a surface resistivity measuring device (Hi Resista-IP manufactured by Mitsubishi Yuka Co., Ltd.), the surface resistivity (Ω / sq) of the film surface (when a coating layer is provided, the coated layer surface) was measured at an applied voltage of 500V. 1×10 12 Less than Ω / sq is particularly good: ◎ 1×10 12 Ω / sq or more to 1×10 13 Less than Ω / sq is good: ○, 1×10 13 When it is Ω / sq or more: ×.

[0106] (4) Initial adhesion After the production of the printed matter described in the experimental examples described below, using Nichiban cellophane adhesive tape (CT405AP-24), it was cut out to a width of 24 mm and a length of 50 mm, and completely adhered with a handy rubber roller so that no air was mixed between the ink layer of the printed matter and the tape. Then, the cellophane adhesive tape was peeled off vertically, and in the area of 24 mm × 50 mm, the remaining area of the printed layer was observed and judged according to the following criteria. In the present invention, 4 or more was regarded as passing. 5: The remaining area of the printed layer is 99% or more of the whole 4: The remaining area of the printed layer is 90% or more and less than 99% of the whole 3: The remaining area of the printed layer is 80% or more and less than 90% of the whole 2: The remaining area of the printed layer is 70% or more and less than 80% of the whole 1: The remaining area of the printed layer is 60% or more and less than 70% of the whole

[0107] (5) Adhesion after storage in high temperature and high environment After manufacturing the printed material as described in the experimental example below, the temperature inside a temperature and humidity test chamber [NAGANO SCIENCE Co., Ltd., Model: LH44-12P] was set to 80°C and the humidity to 90%, and the printed material was stored under these conditions for 3 days. After storage, the printed material was removed and allowed to stand until it reached room temperature. After standing, a piece of Nichiban cellophane adhesive tape (CT405AP-24) was cut to a width of 24 mm and a length of 50 mm, and the tape was completely adhered to the ink layer of the printed material using a handy rubber roller to prevent air from being trapped between the tape and the tape. Then, the cellophane adhesive tape was peeled off vertically, and the remaining area of ​​the printed layer in a 24 mm x 50 mm area was observed and judged according to the following criteria. In this invention, a score of 4 or higher was considered acceptable. 5: The remaining area of ​​the printed layer is 99% or more of the total area. 4: The remaining area of ​​the printed layer is 90% or more, but less than 99% of the total area. 3: The remaining area of ​​the printed layer is 80% or more, but less than 90% of the total area. 2: The remaining area of ​​the printed layer is 70% or more, but less than 80% of the total area. 1: The remaining area of ​​the printed layer is 60% or more, but less than 70% of the total area.

[0108] (7) Apparent density Four 5.00 cm squares of film were cut out to form samples. These four samples were stacked, and the thickness was measured at 10 points using a micrometer to four significant figures. The average stacked thickness was then calculated. This average was divided by 4, and the result was rounded to the fourth decimal place to obtain the average film thickness per sheet (t: μm) to three decimal places. The mass (w: g) of the four samples was also measured to four significant figures using an automatic balance, and the apparent density was calculated using the following formula. The apparent density was rounded to three significant figures. Apparent density (g / cm³) 3 ) = w × 10 4 / (5.00×5.00×t×4)

[0109] (8) Thickness of resin solids in the easily adhering coating layer The resin solids thickness was calculated from the amount of coating applied and the total mass of resin solids contained in the coating.

[0110] (9) b value In accordance with JIS-8722, the color b value of the reflectance was measured using a color difference meter (ZE6000, manufactured by Nippon Denshoku Industries Co., Ltd.). [Examples]

[0111] Next, the present invention will be described in detail using experimental examples, but the present invention is not limited to the following experimental examples.

[0112] (Synthesis of cationic antistatic agents containing nitrogen: A-1) An esterification reaction was carried out at 100°C under a nitrogen atmosphere for 10 hours using 89 g of dimethylaminoethanol and 285 g of stearic acid with 18 carbon atoms. Tetrahydrofuran was added as the quaternization solvent, and a specified amount of dimethyl sulfuric acid was added to the target amine. The reaction was carried out at 70°C for approximately 10 hours. After the reaction, the solvent was removed by distillation under reduced pressure, and isopropanol was added to adjust the solid content to the desired level to obtain isopropanol solution A-1 of a cationic antistatic agent having a quaternary ammonium salt.

[0113] (Synthesis of cationic antistatic agents containing nitrogen element A-2) Using 116 g of N,N-dimethyl-1,3-propanediamine and 285 g of stearic acid, the same treatment as for A-1 was carried out to obtain isopropanol solution A-2 of a cationic antistatic agent having a quaternary ammonium salt.

[0114] (Polyester resin polymerization B-1) In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, 194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass of dimethyl-5-sodium sulfoisophthalate, 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was carried out at a temperature of 160°C to 220°C for 4 hours. The temperature was then raised to 255°C, the reaction system was gradually depressurized, and the reaction was carried out under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain copolymerized polyester resin (B-1). The obtained copolymerized polyester resin (B-1) was pale yellow and transparent. The reduced viscosity of copolymerized polyester resin (B-1) was measured to be 0.70 dl / g. The glass transition temperature determined by DSC was 40°C.

[0115] (Preparation of polyester aqueous dispersion Bw-1) In a reactor equipped with a stirrer, thermometer, and reflux device, 25 parts by mass of polyester resin (B-1) and 10 parts by mass of ethylene glycol n-butyl ether were added and heated at 110°C, stirring to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water were gradually added to the polyester solution while stirring. After the addition, the liquid was cooled to room temperature while stirring to prepare a milky white polyester aqueous dispersion (Bw-1) with a solid content of 30.0% by mass.

[0116] (Preparation of polyester resin solution Bw-2) 97 parts by mass of dimethyl terephthalate, 93 parts by mass of dimethyl isophthalate, 68 parts by mass of ethylene glycol, 116 parts by mass of diethylene glycol, 0.1 parts by mass of zinc acetate, and 0.1 parts by mass of antimony trioxide were charged into a reaction vessel, and a transesterification reaction was carried out at 180°C for 3 hours. Next, 7.1 parts by mass of 5-sodium sulfoisophthalic acid was added, and an esterification reaction was carried out at 240°C for 1 hour, followed by a polycondensation reaction at 250°C under reduced pressure (1.33~0.027 kPa) for 2 hours to obtain a polyester resin with a molecular weight of 22000. 300 parts by mass of this polyester resin and 140 parts by mass of butyl cellosolve were stirred at 160°C for 3 hours to obtain a viscous molten liquid, and water was gradually added to this molten liquid to prepare a homogeneous pale white polyester resin solution (Bw-2) with a solid content of 25.0% by mass after 1 hour.

[0117] (Preparation of polyurethane resin solution C-1 having a polycarbonate structure) 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 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 20 parts by mass of polyethylene glycol monomethyl ether with a number average molecular weight of 700, 53 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2100, 5 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added. The mixture was stirred at 75°C under a nitrogen atmosphere for 3 hours, and it was confirmed that the reaction solution reached the predetermined amine equivalent. Then, the reaction solution temperature was lowered to 50°C, and 3 parts by mass of methyl ethyl ketoxime were added dropwise. After cooling the reaction solution to 40°C, a polyurethane prepolymer solution was obtained. Next, in a reaction vessel equipped with a homodisperser capable of high-speed stirring, 450 g of water was added, the temperature was adjusted to 25°C, and the mixture was stirred for 2000 min. -1 While stirring and mixing, the polyurethane prepolymer solution was added and dispersed in water. Then, under reduced pressure, a water-dispersible polyurethane resin solution (C-1) with a solid content of 35.4% by mass was prepared by removing some of the acetone and water.

[0118] (Preparation of polyurethane resin solution C-2 having a polycarbonate structure) In a four-necked flask equipped with a stirrer, a Liebig condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 31.0 parts by mass of hydrogenated m-xylylene diisocyanate, 7.0 parts by mass of dimethylolpropanoic acid, 60 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 1800, 6 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added. The mixture was stirred under a nitrogen atmosphere at 75°C for 3 hours, and it was confirmed that the reaction solution reached the predetermined amine equivalent. After the reaction solution was cooled to 40°C, 6.65 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, in a reaction vessel equipped with a homodisperser capable of high-speed stirring, 450 g of water was added, the temperature was adjusted to 25°C, and the mixture was stirred for 2000 min. -1 While stirring and mixing, the polyurethane prepolymer solution was added and dispersed in water. Then, under reduced pressure, a water-dispersible polyurethane resin solution (C-2) with a solid content of 35.0% by mass was prepared by removing some of the acetone and water.

[0119] (Preparation of polyurethane resin solution C-3 having a polyester structure) In a four-necked flask equipped with a stirrer, a Liebig condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 82.8 parts by mass of hydrogenated m-xylylene diisocyanate, 25.0 parts by mass of dimethylolpropanoic acid, 2 parts by mass of 3-methyl-1,5-pentanediol, 150.0 parts by mass of polyester diol consisting of terephthalic acid / isophthalic acid / ethylene glycol / diethylene glycol = 50 / 50 / 40 / 60 (molar ratio), and 110 parts by mass of acetone as a solvent were added. The mixture was stirred under a nitrogen atmosphere at 75°C for 3 hours, and it was confirmed that the reaction solution reached the predetermined amine equivalent. Next, the reaction solution was cooled to 40°C, and 19.8 parts by mass of triethylamine was added to obtain a polyurethane polymer solution. Next, 880 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 for 2000 min. -1While stirring and mixing, the polyurethane polymer solution was added and dispersed in water. Then, under reduced pressure, the solvent, acetone, was removed. By adjusting the concentration with water, a polyurethane resin solution (C-3) with a solid content of 30.0% by mass was prepared.

[0120] (Preparation of a polyurethane block isocyanate aqueous dispersion having a polyester structure (C-4)) 200 parts by mass of a polyester (molecular weight 2000) of a bisphenol A ethylene oxide 2-mol adduct and maleic acid was mixed with 33.6 parts by mass of hexamethylene diisocyanate, and the reaction was carried out at 100°C for 2 hours. The temperature of the system was then lowered to 50°C, 73 parts by mass of a 30% sodium bisulfite aqueous solution was added, and the mixture was stirred at 45°C for 60 minutes. The mixture was then diluted with 718 parts by mass of water to obtain a block polyisocyanate aqueous dispersion (C-4) with a solid content of 20.0% by mass. The number of functional groups of this block isocyanate crosslinking agent is 2, and the NCO equivalent is 1300.

[0121] (Experimental Example 1) (1) Preparation of the coating solution The following coating agents were mixed into a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was adjusted to 5.0 / 57.0 / 38.0. In the white, easily adhesive film manufacturing process described later, the solution was applied so that the resin solid content thickness was 450 nm. 2.52 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 17.00 parts by mass Polyurethane resin solution (C-1) 9.60 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0122] (2) Preparation of Master Pellet M1 A pellet mixture consisting of 60% by mass of polymethylpentene resin (Mitsui Chemicals, DX820) with a melt viscosity (ηO) of 1,300 poise, 20% by mass of polystyrene resin (Nippon Polysty Co., Ltd., G797N) with a melt viscosity (ηS) of 3,900 poise, and 20% by mass of polypropylene resin (Grand Polymer Co., Ltd., J104WC) with a melt viscosity of 2,000 poise was supplied to a vented twin-screw extruder heated to 285°C for pre-mixing. This molten resin was continuously supplied to a vented single-screw mixer, mixed and extruded, and the resulting strands were cooled and cut to prepare a cavity-forming agent master pellet (M1).

[0123] (3) Preparation of Master Pellet M2 Furthermore, 50% by mass of polyethylene terephthalate resin with an intrinsic viscosity of 0.62 dl / g produced by an antimony catalyst using a known method was mixed with 50% by mass of anatase-type titanium dioxide particles (manufactured by Fuji Titanium Co., Ltd., TA-300) with an average particle size of 0.3 μm. This mixture was supplied to a vented twin-screw extruder for pre-mixing. This molten resin was continuously supplied to a vented single-screw mixer, mixed, and extruded. The resulting strands were cooled and cut to prepare titanium dioxide-containing master pellets (M2).

[0124] (4) Manufacturing of white, easily adhesive polyester film

[0125] (Preparation of film raw material D1) Film raw material (D1) was prepared by mixing 81% by mass of the polyethylene terephthalate resin with an intrinsic viscosity of 0.62 dl / g, which was vacuum-dried at 140°C for 8 hours, 9% by mass of the master pellet (M1), which was vacuum-dried at 90°C for 4 hours, and 10% by mass of the master pellet (M2).

[0126] (Preparation of unstretched film) The aforementioned film raw material (D1) was mixed with 70% by mass of the same polyethylene terephthalate resin and 30% by mass of the master pellets (M2) used in the preparation of the film raw material (D1) in a Y-layer extruder heated to 285°C, and this mixture was separately supplied to an X-layer extruder heated to 290°C. The molten resin discharged from the Y-layer extruder was guided through an orifice, and the resin discharged from the A-layer extruder was guided through a static mixer to a feed book, and the layer made of film raw material (D1) (Y-layer) and the layer made of polyethylene terephthalate resin and master pellets (M2) (X-layer) were laminated in the order of X-layer / Y-layer / X-layer.

[0127] The molten resin was co-extruded in sheet form from a T-die onto a cooling roll heated to 25°C, and solidified using electrostatic application to produce an unstretched film with a thickness of 510 μm. The discharge rate of each extruder was adjusted so that the thickness ratio of each layer was 1:8:1. The molten resin remained in the melt line for approximately 12 minutes, and the shear rate from the T-die was approximately 150 / second.

[0128] (Preparation of biaxially oriented film) The obtained unstretched film was uniformly heated to 65°C using a heated roll and stretched longitudinally 3.4 times between two pairs of nip rolls with different peripheral speeds (low-speed roll: 2 m / min, high-speed roll: 6.8 m / min). At this time, as an auxiliary heating device for the film, an infrared heating heater (rated output: 20 W / cm) equipped with a gold reflective film in the middle of the nip roll was placed on both sides of the film, 1 cm from the film surface, and heated. The aforementioned coating solution was applied to one side of the uniaxially oriented film obtained in this way using the reverse kiss-coat method. After coating, it was guided to a tenter, heated to 150°C while drying and stretched transversely 3.7 times, the width was fixed and heat-treated at 220°C for 5 seconds, and then relaxed by 4% in the width direction at 200°C to obtain a white, easily adhesive polyester film with a thickness of 50 μm. The b value of this film was 1.6.

[0129] (5) Manufacturing of printed materials (Printed material with a solvent-based ink layer) On an easily adhesive coating layer of an easily adhesive polyester film, "Tetron Ink 900-1 Series 990 Black" screen ink manufactured by Jujo Chemical Co., Ltd. was diluted with "Tetron Standard Solvent" manufactured by Jujo Chemical Co., Ltd., to a ratio of Tetron Ink:Tetron Standard Solvent = 4:1. The ink was then applied using a 250 mesh screen and a squeegee. After ink application, the print was dried and cured at 90°C for 5 minutes using a Yamato Scientific Co., Ltd. dry oven DVS602 to obtain the printed material.

[0130] (Printed materials with an oxidative polymerization type ink layer) A printed material was obtained by printing on an easily adhesive coated layer of an easily adhesive polyester film using an oxidative polymerization type offset ink [manufactured by Toyo Ink Mfg. Ltd., product name "TSP400 G Sumi"] on a printing press [manufactured by Akira Seisakusho Co., Ltd., product name "RI Tester"].

[0131] (Printed material with a fused thermal transfer ink layer) A one-dimensional barcode using an arbitrary JAN code was printed on an easily adhesive coated layer of an easily adhesive polyester film using a Sato Scantronics CL4NX-J thermal transfer printer and Ricoh B110C thermal transfer ribbon ink at a printing speed of 6 inches / second to obtain a printed material.

[0132] (Printed material with an LBP toner layer) Using FUJI XEROX Corporation's ApeosPort-V C3376, an arbitrarily created design was printed onto the easily adhesive coating layer of an easily adhesive polyester film to obtain a printed material.

[0133] (Printed material with a UV-curable ink layer) Printing was performed on an easy-adhesion coating layer of an easy-adhesion polyester film using a UV-curing ink [manufactured by T&K TOKA Co., Ltd., product name "BEST CURE UV161 Indigo S"] on a central impression type printing press. Cell volume: 11 cm³ 3 / m 2The ink was weighed using an anilox roll, transferred to a solid color plate, and then transferred to a film. The transferred ink on the film was cured with a 160 W / cm metal halide UV lamp to obtain a printed product. The time from ink transfer to film to UV light irradiation was 1.88 seconds.

[0134] (Experimental Example 2) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 76.0 / 19.0. 2.52 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 22.67 parts by mass Polyurethane resin solution (C-1) 4.80 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0135] (Experimental Example 3) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 57.0 / 38.0. 2.52 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 17.00 parts by mass Polyurethane resin solution (C-2) 9.71 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0136] (Experimental Example 4) A white, easily adhesive polyester film was obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 57.0 / 38.0. 2.52 parts by mass of a cationic antistatic agent solution containing nitrogen (A-2) (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 17.00 parts by mass Polyurethane resin solution (C-1) 9.60 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0137] (Experimental Example 5) A white, easily adhesive polyester film was obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 57.0 / 38.0. 2.52 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 17.50% by mass) Polyester resin solution (Bw-2) 20.40 parts by mass Polyurethane resin solution (C-1) 9.60 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0138] (Experimental Example 6) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 57.0 / 38.0, and the solution was applied so that the resin solid content thickness was 650 nm. 3.30 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 19.20% by mass) Polyester aqueous dispersion (Bw-1) 30.00 parts by mass Polyurethane resin solution (C-1) 16.95 parts by mass Particles 31.91 parts by mass (Benzoguanamineformaldehyde condensate particles with an average particle size of 2 μm, Solid content concentration 40.00% by mass) Surfactant 0.40 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0139] (Experimental Example 7) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 6.5 / 60.7 / 32.8, and the solution was applied so that the resin solid content thickness was 50 nm. 2.45 parts by mass of a cationic antistatic agent solution containing nitrogen (A-1) (Solid content concentration 15.8% by mass) Polyester aqueous dispersion (Bw-1) 12.35 parts by mass Polyurethane resin solution (C-1) 6.27 parts by mass Surfactant 0.25 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0140] (Experimental Example 8) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 85.5 / 9.5. 2.52 parts by mass of a cationic antistatic agent solution (A) containing nitrogen element (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 25.50 parts by mass Polyurethane resin solution (C-1) 2.40 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0141] (Experimental Example 9) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 28.5 / 67.0. 2.52 parts by mass of a cationic antistatic agent solution (A) containing nitrogen element (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 8.50 parts by mass Polyurethane resin solution (C-1) 16.81 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0142] (Experimental Example 10) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.0 / 57.0 / 38.0. 2.52 parts by mass of a cationic antistatic agent solution (A) containing nitrogen element (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 17.00 parts by mass Polyurethane resin solution (C-3) 11.33 parts by mass Particles 25.15 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0143] (Experimental Example 11) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.8 / 33.0 / 61.2. 2.83 parts by mass of a cationic antistatic agent solution (A) containing nitrogen element (Solid content concentration 17.50% by mass) Polyester aqueous dispersion (Bw-1) 9.33 parts by mass Polyurethane resin solution (C-4) 26.00 parts by mass Particle (a) 16.31 parts by mass (Silica particles with an average particle size of 0.45 μm, solid content concentration of 40.00% by mass) Particle (b) 5.44 parts by mass (Silica particles with an average particle size of 1.00 μm, solid content concentration of 40.00% by mass) Surfactant 0.15 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0144] (Experimental Example 12) A white, easily adhering polyester film and printed material were obtained in the same manner as in Experimental Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, the solid content mass ratio of the nitrogen-containing cationic antistatic agent / polyester resin / polyurethane resin solution was changed to 5.8 / 33.0 / 61.2, and the solution was applied so that the resin solid content thickness was 650 nm. 2.91 parts by mass of a cationic antistatic agent solution (A) containing nitrogen element (Solid content concentration 19.20% by mass) Polyester aqueous dispersion (Bw-1) 11.67 parts by mass Polyurethane resin solution (C-4) 32.50 parts by mass Particles 21.27 parts by mass (Benzoguanamine particles with an average particle size of 2.00 μm, solid content concentration of 40.00% by mass) Surfactant 0.45 parts by mass (Silicone-based, solid content concentration 10% by mass)

[0145] Tables 1 and 2 summarize the evaluation results for each experimental case.

[0146] [Table 1]

[0147] [Table 2]

[0148] The printed materials obtained in Experimental Examples 1-7 exhibited excellent adhesion to various inks and toners. In particular, the adhesion to active energy ray curing ink layers, such as ultraviolet (UV) curing inks, did not deteriorate even when stored in a high-temperature, high-humidity environment. On the other hand, in Experimental Examples 8-12, the A value, B / A value, or contact angle with water of the substrate with the easily adhering coating layer was inappropriate, resulting in unsatisfactory antistatic properties and adhesion to various ink layers when stored in a high-temperature, high-humidity environment after printing. [Industrial applicability]

[0149] According to the present invention, it is possible to provide printed materials that exhibit excellent adhesion to various ink compositions and whose adhesion to the ink layer does not deteriorate even when stored in a high-temperature, high-humidity environment. [Explanation of symbols]

[0150] Thin solid line: Measured data of the N1s spectrum of the surface of the easily adhering coated layer. Dotted line: Curve showing the ionized nitrogen element peak obtained by peak separation of the N1s spectrum. Dashed line: Curve showing the peak of the unionized nitrogen element obtained by peak separation in the N1s spectrum. (1): Ionized nitrogen peak (2) Unionized nitrogen peak

Claims

1. A printed material comprising a polyester film substrate having an easily adhesive coating layer, and at least one ink layer selected from UV-curable ink, solvent-based ink, oxidative polymerization ink, thermal transfer ink ribbon, and LBP toner laminated on the easily adhesive coating layer, The nitrogen ion concentration A (at%) and nitrogen element ratio B (at%), based on surface elemental distribution measurement of the surface of the easy-adhesion coated layer by X-ray photoelectron spectroscopy, satisfy the following formulas (i) and (ii), and Contact angle θH of the easily adhering coated layer surface with water ２ O satisfies the following equation (iii), The aforementioned easy-adhesion coating layer is formed by curing a composition containing a cationic antistatic agent having a nitrogen element and a polyurethane resin. The aforementioned cationic antistatic agent having a nitrogen element is an antistatic agent having a linear alkyl group. The polyurethane resin is a polyurethane resin having a polycarbonate structure or a polyurethane resin having a polyester structure. The nitrogen ion concentration A (at%) is derived from a cationic antistatic agent component containing the element nitrogen. The nitrogen element ratio B (at%) is derived from the polyurethane resin. printed matter. (i) A (at%) > 0.4 (ii) 2.0 ≦ B / A ≦ 5.0 (iii)60°≦θ H ２ O≦70°

2. The composition that forms the easy-adhesion coating layer comprises a polyester resin, In the above composition, when the total solid content of the cationic antistatic agent, the polyester resin, and the polyurethane resin is 100% by mass, the content of the cationic antistatic agent is 4.0 to 5.5%, and the content of the polyurethane resin is 20 to 55% by mass. The printed material according to claim 1.

3. The printed article according to claim 1, wherein the polyester film substrate is a white polyester film substrate containing inorganic particles and / or a thermoplastic resin incompatible with the polyester resin.

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