Printed materials

Abstract

The present invention provides a printed object using a readily adhesive polyester film that is highly transparent, has blocking resistance, has favorable adhesiveness with respect to various ink compositions, and in particular has favorable adhesiveness with respect to UV-curing ink during low-irradiation processing or during high-speed printing. The printed object is obtained by laminating at least one ink layer selected from among UV-curing inks, solvent-type inks, oxidation polymerization-type inks, heat-transfer ink ribbon, and LBP toner onto a coating layer of easily adhesive polyester film in which the coating layer is provided on at least one surface of a polyester film base material, wherein the coating layer is obtained by curing a composition containing urethane resin having a polycarbonate structure, a cross-linking agent, and a polyester resin, and has specific properties.

Description

[Technical Field]

[0001] The present invention relates to a printed matter having excellent adhesion to various ink layers, and more specifically to a printed matter having a coating layer that is highly adhesive to all kinds of ink layers, such as ultraviolet (UV) curable ink, solvent-based ink, oxidative polymerization ink, thermal transfer ink ribbon, and LBP toner. [Background technology]

[0002] Biaxially oriented polyester films are widely used in various industrial and consumer applications due to their balance of mechanical strength, heat resistance, chemical resistance, dimensional stability, and price. They are particularly indispensable for commercial printing applications involving printing on transparent films, such as decorative illumination plates, dummy cans, and labels. However, polyester films generally have poor adhesion to printing inks, so an anchor coating layer made of a resin with high adhesive properties is typically provided. For relatively polar films, primarily polyester films, the use of water-soluble or water-dispersible polyester resins or acrylic resins has been proposed (see, for example, Patent Documents 1, 2, 3, and 4). However, the polyester resins tend to have poor blocking resistance in film rolls, and the acrylic resins tend to have poor adhesion to base films and printing inks. To address these issues, the use of a mixture of the polyester resin and the acrylic resin has been proposed (see, for example, Patent Document 5), but the improvement in these drawbacks is insufficient. Furthermore, the use of various modified polyesters, primarily graft-modified polyesters, has also been proposed. It has also been disclosed that resins obtained by grafting unsaturated bond-containing compounds onto water-soluble or water-dispersible hydrophilic group-containing polyester resins are suitable as anchor coating agents for polyester films (see, for example, Patent Documents 6, 7, and 8). However, their performance is still insufficient in terms of adhesion and water resistance. Furthermore, graft-modified polyester resins have been disclosed (see, for example, Patent Documents 9 and 10), but their poor cohesive strength leaves problems such as peeling and scratches.

[0003] In printing applications, these can lead to fatal defects such as scratches, loss of coating and lubricant particles, and poor ink transfer and peeling. This is an essential property, especially in sheet-fed offset printing applications, where strong friction is experienced during paper feeding and transport, and where the use of UV-curable inks requires a high level of adhesion.

[0004] In recent years, the printing industry has been moving toward higher printing speeds in order to improve productivity. As printing speeds increase with UV-curable inks, the time required from ink application to UV irradiation and the cumulative amount of UV light decrease. This means that the interaction between the ink and the polyester film and the coating layer weakens. Therefore, the coating layer must have higher adhesion to the UV-curable ink. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 54-43017 [Patent Document 2] Special Publication No. 49-10243 [Patent Document 3] Japanese Patent Application Publication No. 52-19786 [Patent Document 4] Japanese Patent Application Publication No. 52-19787 [Patent Document 5] Japanese Unexamined Patent Publication No. 58-124651 [Patent Document 6] Japanese Patent Application Publication No. 2-3307 [Patent Document 7] Japanese Patent Application Publication No. 2-171243 [Patent Document 8] Japanese Patent Application Publication No. 2-310048 [Patent Document 9] Japanese Patent Application Publication No. 3-273015 [Patent Document 10] Japanese Patent Application Publication No. 3-67626 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the problems of the prior art. That is, an object of the present invention is to provide a printed matter using an easily adhesive polyester film that has high transparency, blocking resistance, and good adhesion to a variety of ink compositions, particularly to various ink compositions including UV-curable inks, during low-dose processing or high-speed printing. [Means for solving the problem]

[0007] In the process of investigating the causes of the above problems in order to solve them, the present inventors discovered that the problems of the present invention can be solved when a polyester film substrate has a coating layer on at least one surface thereof that contains a crosslinking agent, a urethane resin having a polycarbonate structure, and a polyester resin, and when the nitrogen atom ratio in the coating layer and the OCOO bond ratio on the surface of the coating layer opposite the polyester film substrate satisfy specific conditions, leading to the completion of the present invention.

[0008] The above object can be achieved by the following means. 1. A printed matter comprising a highly adhesive polyester film having a coating layer on at least one surface of the polyester film substrate, 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 coating layer, wherein the coating layer is formed by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin, and the coating layer satisfies the following formulas (i) to (iii) when, in a nitrogen element distribution curve based on element distribution measurement of the coating layer in the depth direction by X-ray photoelectron spectroscopy, the nitrogen atomic ratio on the surface of the coating layer opposite the polyester film substrate is A (at%), the maximum value of the nitrogen atomic ratio is B (at%), the etching time at which the nitrogen atomic ratio reaches the maximum value B (at%) is b (seconds), and the etching time at which the nitrogen atomic ratio becomes 1 / 2B (at%) after b (seconds) is c (seconds), and the X-ray photoelectron spectroscopy A printed matter that satisfies the following formula (iv), where the total peak area derived from each bond type in the C1s spectral region in a surface analysis spectrum measured by a spectroscopic method is 100 (%) and the peak area derived from an OCOO bond is X (%). (i) 0.5 ≦ BA(at%) ≦ 3.0 (ii) 30 ≦ b(seconds) ≦ 180 (iii) 30 ≦ cb(sec) ≦ 300 (iv) 2.0≦ X(%) ≦ 10.0 2. A printed matter in which the haze of the highly adhesive polyester film described in 1 above is 1.5% or less. [Effects of the Invention]

[0009] The present invention enables the production of various printed materials with excellent adhesion between the substrate and the ink layer. The film exhibits excellent adhesion with various ink compositions, including UV-curable inks, particularly during low-dose processing or high-speed printing. Furthermore, the highly adhesive polyester film of the present invention has high transparency and excellent blocking resistance. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a distribution curve of nitrogen element based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy for the highly adhesive polyester film of Example 2. [Figure 2] FIG. 1 is an explanatory diagram for determining BA, b, and cb from a nitrogen element distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy. [Figure 3] 1 is a nitrogen element distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy for the highly adhesive polyester film of Example 5. [Figure 4] 1 is a distribution curve of nitrogen element based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy for the highly adhesive polyester film of Experimental Example 6. [Figure 5] 1 is a graph showing the analysis results of the C1s spectrum of the surface region of the coating layer of the highly adhesive polyester film of Example 6. [Figure 6] 1 is a graph showing the analysis results of the C1s spectrum of the surface region of the coating layer of the highly adhesive polyester film of Experimental Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Polyester film base) 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 copolymerized polyester resins in which a portion of the diol component or dicarboxylic acid component of the above-mentioned polyester resins is replaced with a copolymerization component such as the following. For example, the copolymerization component may include diol components such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, and polyalkylene glycol, and dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, 5-sodium isophthalic acid, and 2,6-naphthalenedicarboxylic acid.

[0012] The polyester resin preferably used 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 preferred in terms of the balance between physical properties and cost. Furthermore, the polyester film substrate made of these polyester resins is preferably a biaxially oriented polyester film, which can improve chemical resistance, heat resistance, mechanical strength, etc.

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

[0014] The polyester film substrate in the present invention may be a single-layer polyester film, a two-layer structure having different components, or a polyester film substrate consisting of at least three layers, including an outer layer and an inner layer.

[0015] (Explanation of characteristic values ​​in the present invention) The highly adhesive polyester film of the present invention preferably has a coating layer on at least one surface of the polyester film substrate as described above. The coating layer is formed by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin. The expression "formed by curing a composition" is used here because it is extremely difficult to accurately describe the chemical composition of the urethane resin having a polycarbonate structure, the crosslinking agent, and the polyester resin in a cured state after forming a crosslinked structure with the crosslinking agent. Furthermore, it is preferable that the maximum value of the nitrogen element distribution curve based on element distribution measurement in the depth direction of the coating layer is located near the surface of the coating layer on the side opposite the polyester film substrate, as this can improve transparency and blocking resistance. Furthermore, it is preferable that an appropriate amount of polycarbonate structure is present on the surface of the coating layer on the side opposite the polyester film substrate, as this can improve UV ink adhesion during low-dose processing and high-speed printing.

[0016] The characteristics of the coating layer in the above-mentioned highly adhesive polyester film are described below. First, a nitrogen element distribution curve based on element distribution measurements in the depth direction of the coating layer was plotted using X-ray photoelectron spectroscopy (ESCA). Spectra were collected every 30 seconds up to an etching time of 120 seconds, and every 60 seconds thereafter. As shown in Figure 2, the horizontal axis represents the etching time (unit: seconds) from the surface of the coating layer, and the vertical axis represents the ratio of nitrogen atoms to the total amount of carbon, oxygen, nitrogen, and silicon atoms (nitrogen atomic ratio, unit: at%). The nitrogen atomic ratio on the surface of the coating layer opposite the polyester film substrate is designated A (at%), the maximum nitrogen atomic ratio is designated B (at%), the etching time at which the nitrogen atomic ratio reaches the maximum value B (at%) is designated b (seconds), and the etching time at which the nitrogen atomic ratio reaches 1 / 2B (at%) after b (seconds) is designated c (seconds). From the data obtained, B (at%) and cb (seconds) are calculated. The nitrogen atomic ratio A (at %) on the surface of the coating layer opposite to the polyester film substrate is the nitrogen atomic ratio when the etching time is 0 (seconds).

[0017] When the characteristic values ​​read from the nitrogen element distribution curve based on the element distribution measurement in the depth direction of the coating layer satisfy the following relationship, a highly adhesive polyester film having excellent transparency, blocking resistance, and adhesion to solvent-based ink layers can be obtained. (i) 0.5 ≦ BA(at%) ≦ 3.0 (ii) 30 ≦ b(seconds) ≦ 180 (iii) 30 ≦ cb(sec) ≦ 300

[0018] The lower limit of BA is preferably 0.5 at%, more preferably 0.6 at%, even more preferably 0.7 at%, particularly preferably 0.8 at%, and most preferably 0.9 at%. A content of 0.5 at% or more is preferable because the amount of urethane resin component having toughness is sufficient, blocking resistance is obtained, and excellent adhesion to the solvent-based ink layer is also obtained. The upper limit of BA is preferably 3.0 at%, more preferably 2.9 at%, even more preferably 2.8 at%, particularly preferably 2.7 at%, and most preferably 2.5 at%. A content of 3.0 at% or less is preferable because low haze and transparency are obtained.

[0019] The lower limit of b is preferably 30 seconds, and if it is 30 seconds or more, the toughness of the coating layer surface on the side opposite the polyester film substrate is maintained, and blocking resistance is obtained, which is preferable. The upper limit of b is preferably 180 seconds, more preferably 120 seconds, even more preferably 90 seconds, and particularly preferably 60 seconds. If it is 180 seconds or less, the toughness of the coating layer surface on the side opposite the polyester film substrate is maintained, and blocking resistance is good, which is preferable.

[0020] The upper limit of cb is preferably 300 seconds, more preferably 240 seconds, and even more preferably 180 seconds. A time of 300 seconds or less is preferable because the urethane resin component in the coating layer does not become excessive, resulting in low haze and transparency. The lower limit of cb is 30 seconds or more because spectrum collection is performed every 30 seconds from the start of measurement until the etching time reaches 120 seconds.

[0021] In the present invention, it is preferred that most of the polycarbonate structural moieties in the urethane resin in the coating layer constituting the highly adhesive polyester film are localized on the surface of the coating layer opposite the polyester film substrate. This is because the presence of an appropriate amount of polycarbonate structural moieties on this surface improves adhesion to a variety of ink compositions. On the other hand, it has also been found that the presence of polycarbonate structural moieties on this surface increases flexibility and may not necessarily result in sufficient blocking resistance. Therefore, as described above, when the various characteristic values ​​read from the nitrogen element distribution curve based on element distribution measurement in the depth direction of the coating layer satisfy the following relationship, a highly adhesive polyester film that also possesses excellent transparency and blocking resistance can be obtained. (i) 0.5 ≦ BA(at%) ≦ 3.0 (ii) 30 ≦ b(seconds) ≦ 180 (iii) 30 ≦ cb(sec) ≦ 300

[0022] In the highly adhesive polyester film of the present invention, One way to satisfy this requirement is to synthesize and polymerize a urethane resin having a polycarbonate structure that forms the coating layer, by synthesizing and polymerizing a polycarbonate polyol component and a polyisocyanate component, the mass ratio of the polycarbonate polyol component to the polyisocyanate component being within the range of 0.5 to 2.5, the molecular weight of the polycarbonate polyol component being 500 to 1800, and the solid content of the crosslinking agent being 10 to 50 mass% when the total solid content of the polyester resin, urethane resin, and crosslinking agent in the coating solution is 100 mass%. Furthermore, by using a blocked isocyanate as the crosslinking agent, and using a blocked isocyanate having a tri- or higher functional isocyanate group, efficient adjustment of the BA is possible.

[0023] As described above, it is preferable that the majority of the polycarbonate structural moieties in the urethane resin in the coating layer of the present invention are present in a certain proportion on the surface of the coating layer opposite the polyester film substrate. In the present invention, in a surface analysis spectrum measured by X-ray photoelectron spectroscopy, the total area of ​​the peaks attributable to each bond type in the C1s spectral region is 100(%), and the peak area attributable to the OCOO bond (which is a polycarbonate structure) is X(%), and the values ​​are expressed as percentages.

[0024] Here, the ratio X (%) of OCOO bonds (which are polycarbonate structures) in the surface region is evaluated by X-ray photoelectron spectroscopy (ESCA). Figures 5 and 6 are graph examples showing the analysis results of the C1s spectrum of the surface region of the highly adhesive polyester film of Example 6 and Experimental Example 1, respectively, which will be described later. The gray solid line represents the measured data of the C1s spectrum. The peaks of the obtained measured spectrum are separated into multiple peaks, and the bond species corresponding to each peak are identified from the position and shape of each peak. Furthermore, curve fitting is performed on the peaks derived from each bond species, and the peak area can be calculated. The coating layer in the present invention is made of a urethane resin having a polycarbonate structure, a blocked isocyanate having a tri- or higher functional isocyanate group, and a urethane resin having a polycarbonate structure and a blocked isocyanate having a tri- or higher functional isocyanate group. The coating layer contains a typical crosslinking agent and a polyester resin, and in the case of such a coating layer, peaks of the bond species (1) to (6) in Table 1 can be detected. The bond species (1) to (6) in Table 1 are not necessarily limited to the bond species shown in Table 1, and may contain small amounts of similar bond species. Here, in Figure 5 relating to Example 6, the C=O bond peak (3) and the π-π* bond peak (6) in Table 1 do not appear. Also, in Figure 6 relating to Experimental Example 1, the C=O bond peak (3) in Table 1 and the π-π* bond peak (6) do not appear. The O bond peak and the O C O O bond peak of (5) are not visible. The percentage X (%) is the percentage of peak (5) when the total peak area of ​​peaks (1) to (6) is 100%. It can be said to be the area ratio expressed as a percentage (%).

[0025] [Table 1]

[0026] The preferred range of the peak area X (%) derived from the OCOO bond is as follows: The lower limit of X is preferably 2.0%, more preferably 2.5%, even more preferably 3.0%, particularly preferably 3.5%, and most preferably 4.0%. When X is 2.0% or more, ink adhesion can be effectively satisfied, which is preferable. The upper limit of X is preferably 10.0%, more preferably 9.0%, even more preferably 8.0%, particularly preferably 7.5%, and most preferably 7%. When X is 10.0% or less, the flexibility of the surface layer does not become too high, and blocking resistance can be easily obtained, which is preferable.

[0027] In the method for producing the highly adhesive polyester film of the present invention, when synthesizing and polymerizing the urethane resin having a polycarbonate structure that forms the coating layer, it is preferable that the mass ratio of the polycarbonate polyol component to the polyisocyanate component is 0.5 or more, and that the urethane resin content is 5% by mass to 50% by mass when the total solid content of the polyester resin, the urethane resin having a polycarbonate structure, and the crosslinking agent in the coating solution is 100% by mass, because this effectively achieves an X characteristic value based on the C1s spectral region in the range of 2.0 to 10.0%.

[0028] (coating layer) In order to improve adhesion to the ink layer, the highly adhesive polyester film of the present invention preferably has a coating layer formed from a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin laminated on at least one side thereof. The coating layer may be formed on both sides of the polyester film, or may be formed on only one side of the polyester film, with a different resin coating layer formed on the other side.

[0029] The composition of each coating layer will be described in detail below. (urethane resin) The urethane resin having a polycarbonate structure in the present invention has urethane bond moieties derived from at least a polycarbonate polyol component and a polyisocyanate component, and further contains a chain extender as required.

[0030] The lower limit of the mass ratio of the polycarbonate polyol component to the polyisocyanate component (mass of the polycarbonate polyol component / mass of the polyisocyanate component) when synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention is preferably 0.5, more preferably 0.6, even more preferably 0.7, particularly preferably 0.8, and most preferably 1.0. A ratio of 0.5 or more is preferable because the proportion X of O-C, O-O bonds on the surface of the coating layer can be efficiently adjusted to 2% or more. The upper limit of the mass ratio of the polycarbonate polyol component to the polyisocyanate component when synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention is preferably 2.5, more preferably 2.2, even more preferably 2.0, particularly preferably 1.7, and most preferably 1.5. A ratio of 2.5 or less is preferable because the proportion X of O-C, O-O bonds on the surface of the coating layer can be efficiently adjusted to 10% or less. Furthermore, in the nitrogen distribution curve based on the element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, BA can be effectively adjusted to 0.5 at % or more, and cb can be effectively adjusted to 300 seconds or less.

[0031] The polycarbonate polyol component used for synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention preferably contains an aliphatic polycarbonate polyol, which has excellent heat resistance and hydrolysis resistance. Examples of the aliphatic polycarbonate polyol include an aliphatic polycarbonate diol and an aliphatic polycarbonate triol, and the aliphatic polycarbonate diol is preferably used. Examples of the aliphatic polycarbonate diol used for synthesizing and polymerizing the urethane resin 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.

[0032] The number average molecular weight of the polycarbonate polyol in the present invention is preferably 500 to 1800, more preferably 600 to 1700, and most preferably 700 to 1500. When it is 500 or more, the proportion X of OCOO bonds on the coating layer surface can be effectively adjusted to 10% or less, which is preferable. When it is 1800 or less, it is possible to effectively adjust BA to 0.5 or more and cb to 300 seconds or less in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, which is preferable.

[0033] Examples of polyisocyanates used in the synthesis and polymerization of the urethane resin having a polycarbonate structure in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, and polyisocyanates obtained by pre-adding one or more of these compounds with trimethylolpropane or the like. The use of the aromatic aliphatic diisocyanates, alicyclic diisocyanates, or aliphatic diisocyanates described above is preferred because it does not cause yellowing problems. Furthermore, it is also preferred because it does not form an overly rigid coating film, can alleviate stress due to thermal shrinkage of the polyester film substrate, and provides good adhesion.

[0034] Examples of chain extenders 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; and water.

[0035] The coating layer in the present invention is preferably formed using an aqueous coating liquid by the in-line coating method described below. Therefore, the urethane resin of the present invention is preferably water-soluble or water-dispersible. The term "water-soluble or water-dispersible" means that the resin is dispersible in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

[0036] To impart water dispersibility to urethane resins, sulfonic acid (salt) groups or carboxylic acid (salt) groups can be introduced (copolymerized) into the urethane molecular structure. To maintain moisture resistance, it is preferable to introduce weakly acidic carboxylic acid (salt) groups. Nonionic groups such as polyoxyalkylene groups can also be introduced.

[0037] To introduce carboxylic acid (salt) groups into a urethane resin, for example, a polyol compound having a carboxylic acid group, such as dimethylolpropanoic acid or dimethylolbutanoic acid, is introduced as a copolymerization 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 alone or in combination of two or more.

[0038] When a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component to impart water dispersibility, the molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is preferably 3 to 60 mol%, and more preferably 5 to 40 mol%, when the total polyisocyanate components of the urethane resin are taken as 100 mol%. If the molar ratio is less than 3 mol%, water dispersibility may be difficult to achieve. If the molar ratio is more than 60 mol%, water resistance may be reduced, which may result in reduced moist heat resistance.

[0039] The urethane resin of the present invention may have a blocked isocyanate bonded to the end to improve hardness.

[0040] (Crosslinking agent) In the present invention, the crosslinking agent contained in the coating layer-forming composition is preferably a blocked isocyanate, more preferably a trifunctional or higher functional blocked isocyanate, and particularly preferably a tetrafunctional or higher functional blocked isocyanate. These improve blocking resistance. The use of a blocked isocyanate crosslinking agent is preferable because it effectively adjusts the BA to 0.5 at% or more in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy.

[0041] The lower limit of the boiling point of the blocking agent for the blocked isocyanate is preferably 150°C, more preferably 160°C, even more preferably 180°C, particularly preferably 200°C, and most preferably 210°C. The higher the boiling point of the blocking agent, the more suppressed is the volatilization of the blocking agent by heat addition during the drying process after application of the coating liquid or during the film formation process in the case of an in-line coating method, thereby suppressing the occurrence of minute unevenness on the coated surface and improving the transparency of the film. The upper limit of the boiling point of the blocking agent is not particularly limited, but from the viewpoint of productivity, it is thought that the upper limit is about 300°C. Since the boiling point is related to the molecular weight, in order to increase the boiling point of the blocking agent, it is preferable to use a blocking agent with a large molecular weight, and the molecular weight of the blocking agent is preferably 50 or more, more preferably 60 or more, and even more preferably 80 or more.

[0042] The upper limit of the dissociation temperature of the blocking agent is preferably 200°C, more preferably 180°C, even more preferably 160°C, particularly preferably 150°C, and most preferably 120°C. The blocking agent dissociates from the functional group by thermal addition during the drying process after application of the coating liquid or during the film formation process in the case of in-line coating, generating a regenerated isocyanate group. This allows the crosslinking reaction with urethane resins and the like to proceed, improving adhesion. When the dissociation temperature of the blocked isocyanate is below the above temperature, the dissociation of the blocking agent proceeds sufficiently, resulting in good adhesion, particularly good moist heat resistance.

[0043] Examples of blocking agents in the present invention that have a blocked isocyanate dissociation temperature of 120°C or lower and a boiling point of 150°C or higher include bisulfite compounds such as sodium bisulfite, pyrazole compounds such as 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 4-nitro-3,5-dimethylpyrazole, active methylene compounds such as malonic acid diesters (dimethyl malonate, diethyl malonate, di-n-butyl malonate, and di-2-ethylhexyl malonate), methyl ethyl ketone, and triazole compounds such as 1,2,4-triazole. Of these, pyrazole compounds are preferred from the standpoints of wet heat resistance and yellowing.

[0044] The polyisocyanate, which is the precursor of the blocked isocyanate in the present invention, can be obtained by introducing a diisocyanate, such as a urethane-modified diisocyanate, an allophanate-modified diisocyanate, a urea-modified diisocyanate, a biuret-modified diisocyanate, a uretdione-modified diisocyanate, a uretoimine-modified diisocyanate, an isocyanurate-modified diisocyanate, or a carbodiimide-modified diisocyanate.

[0045] Diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, phenylene diisocyanate, tetramethylxylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-diphenyl Examples of suitable diisocyanates include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylpropane diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate; aromatic aliphatic diisocyanates such as xylylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane; and aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate. From the viewpoints of transparency, adhesion, and moist heat resistance, aliphatic and alicyclic isocyanates and their modified products are preferred, and are preferred for optical applications that require high transparency and no yellowing.

[0046] The blocked isocyanate of the present invention can introduce hydrophilic groups into the precursor polyisocyanate to impart water solubility or water dispersibility. Examples of hydrophilic groups include (1) quaternary ammonium salts of dialkylamino alcohols and quaternary ammonium salts of dialkylaminoalkylamines, (2) sulfonates, carboxylates, and phosphates, and (3) polyethylene glycols and polypropylene glycols capped at one end with an alkoxy group. When a hydrophilic moiety is introduced, the resulting polymer will be (1) cationic, (2) anionic, or (3) nonionic. Since many other water-soluble resins are anionic, anionic or nonionic polymers are preferred because they are easily compatible with other resins. Furthermore, anionic polymers have excellent compatibility with other resins, and nonionic polymers lack ionic hydrophilic groups, which improves resistance to moist heat.

[0047] The anionic hydrophilic group preferably has a hydroxyl group for introduction into polyisocyanate and a carboxylic acid group for imparting hydrophilicity. Examples include glycolic acid, lactic acid, tartaric acid, citric acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypivalic acid, dimethylolacetic acid, dimethylolpropanoic acid, dimethylolbutanoic acid, and polycaprolactone having a carboxylic acid group. To neutralize the carboxylic acid group, an organic amine compound is preferred. Examples include linear or branched primary, secondary, or tertiary amines having 1 to 20 carbon atoms, such as ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, and ethylenediamine; cyclic amines, such as morpholine, N-alkylmorpholine, and pyridine; and hydroxyl group-containing amines, such as monoisopropanolamine, methylethanolamine, methylisopropanolamine, dimethylethanolamine, diisopropanolamine, diethanolamine, triethanolamine, diethylethanolamine, and triethanolamine.

[0048] The nonionic hydrophilic group preferably has 3 to 50 repeating units of ethylene oxide and / or propylene oxide in polyethylene glycol or polypropylene glycol capped at one end with an alkoxy group, more preferably 5 to 30. Small repeating units result in poor compatibility with the resin and increased haze, while large repeating units may result in reduced adhesion under high temperature and humidity conditions. To improve water dispersibility, the blocked isocyanate of the present invention can be supplemented with nonionic, anionic, cationic, or amphoteric surfactants. Examples of such surfactants include nonionic surfactants such as polyethylene glycol and polyhydric alcohol fatty acid esters, anionic surfactants such as fatty acid salts, alkyl sulfates, alkylbenzene sulfonates, sulfosuccinates, and alkyl phosphates, cationic surfactants such as alkylamine salts and alkylbetaines, and surfactants such as amine carboxylates, amine sulfonates, and sulfate ester salts.

[0049] In addition to water, a water-soluble organic solvent may also be contained. For example, the organic solvent used in the reaction may be removed, and another organic solvent may be added.

[0050] (polyester resin) The polyester resin used to form the coating layer in the present invention may be a linear one, but is more preferably a polyester resin containing a dicarboxylic acid and a branched glycol as constituent components. The dicarboxylic acid referred to here includes, as its main component, terephthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid, 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, the branched glycol refers to a diol having a branched alkyl group, and examples thereof 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.

[0051] The polyester resin preferably contains the branched glycol component, which is a more preferred embodiment of the present invention, at a ratio of 10 mol % or more, and more preferably 20 mol % or more, of the total glycol components. Ethylene glycol is the most preferred glycol component other than the above compounds. Small amounts of diethylene glycol, propylene glycol, butanediol, hexanediol, or 1,4-cyclohexanedimethanol may also be used.

[0052] The dicarboxylic acid used as a component of the polyester resin is most preferably terephthalic acid or isophthalic acid. Small amounts of other dicarboxylic acids, particularly aromatic dicarboxylic acids such as diphenylcarboxylic acid and 2,6-naphthalenedicarboxylic acid, may be added and copolymerized. In addition to the dicarboxylic acids, 5-sulfoisophthalic acid is preferably copolymerized in an amount of 1 to 10 mol % to impart water dispersibility to the copolymerized polyester resin. Examples of such dicarboxylic acids include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfonaphthaleneisophthalic-2,7-dicarboxylic acid, 5-(4-sulfophenoxy)isophthalic acid, and salts thereof.

[0053] When the total solid content of the polyester resin, urethane resin having a polycarbonate structure, and crosslinking agent in the coating solution is taken as 100% by mass, the lower limit of the crosslinking agent content is preferably 5% by mass, more preferably 7% by mass, even more preferably 10% by mass, and most preferably 12% by mass. A content of 5% by mass or more is preferred because it is easy to adjust BA to 0.5 at% or more in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy. The upper limit of the crosslinking agent content is preferably 50% by mass, more preferably 40% by mass, even more preferably 35% by mass, and most preferably 30% by mass. A content of 50% by mass or less is preferred because it is easy to adjust cb to 300 seconds or less in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy.

[0054] When the total solid content of the polyester resin, urethane resin having a polycarbonate structure, and crosslinking agent in the coating solution is taken as 100% by mass, the lower limit of the content of the urethane resin having a polycarbonate structure is preferably 5% by mass. A content of 5% by mass or more is preferred because it makes it easier to adjust the proportion X of OC-OO bonds on the coating layer surface to 2.0% or more. The upper limit of the content of the urethane resin having a polycarbonate structure is preferably 50% by mass, more preferably 40% by mass, even more preferably 30% by mass, and most preferably 20% by mass. A urethane resin content of 50% by mass or less is preferred because it makes it easier to adjust the proportion X of OC-OO bonds on the coating layer surface to 10.0% or less.

[0055] When the total solid content of the polyester resin, urethane resin, and crosslinking agent in the coating solution is taken as 100% by mass, the lower limit of the polyester resin content is preferably 10% by mass, more preferably 20% by mass, even more preferably 30% by mass, particularly preferably 35% by mass, and most preferably 40% by mass. A polyester resin content of 10% by mass or more is preferred because it improves adhesion between the coating layer and the polyester film substrate. The upper limit of the polyester resin content is preferably 70% by mass, more preferably 67% by mass, even more preferably 65% ​​by mass, particularly preferably 62% by mass, and most preferably 60% by mass. A polyester resin content of 70% by mass or less is preferred because it improves the moist heat resistance of the printed matter after UV ink processing.

[0056] (additives) The coating layer of the present invention may contain known additives, such as surfactants, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic particles, antistatic agents, and nucleating agents, within the range that does not impair the effects of the present invention.

[0057] In the present invention, it is also a preferred embodiment to add particles to the coating layer in order to further improve the blocking resistance of the coating layer. Examples of particles to be contained in the coating layer in the present invention include titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, etc., or mixtures thereof, and further include other general inorganic particles such as calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, etc., used in combination with other inorganic particles, and organic polymer particles such as styrene-based, acrylic-based, melamine-based, benzoguanamine-based, and silicone-based particles.

[0058] The average particle size of the particles in the coating layer (average particle size based on the number of particles as measured by a scanning electron microscope (SEM); the same applies hereinafter) is preferably 0.04 to 2.0 μm, more preferably 0.1 to 1.0 μm. When the average particle size of the inactive particles is 0.04 μm or more, it is easy to form irregularities on the film surface, which improves the handling properties of the film, such as its slipperiness and winding ability, and improves the processability during lamination, which is preferable. On the other hand, when the average particle size of the inactive particles is 2.0 μm or less, it is preferable that the particles are less likely to fall off. The particle concentration in the coating layer is preferably 1 to 20 mass % of the solid components.

[0059] The average particle size of the particles was measured by observing the particles on the cross section of the highly adhesive polyester film with a scanning electron microscope, observing 30 particles, and determining the average particle size as the average value.

[0060] The shape of the particles is not particularly limited as long as it satisfies the objectives of the present invention, and spherical particles and irregular, non-spherical particles can be used. The particle size of irregular particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is the value obtained by dividing the observed particle area by π, calculating the square root, and then multiplying it by two.

[0061] (Production of highly adhesive polyester film) The method for producing the highly adhesive polyester film of the present invention will be described using an example in which a polyethylene terephthalate (hereinafter sometimes abbreviated as PET) film substrate is used, but the method is not limited to this.

[0062] After thorough vacuum drying, the PET resin is fed to an extruder, and the molten PET resin at about 280°C is extruded from a T-die onto a rotating cooling roll in the form of a sheet, which is then cooled and solidified by electrostatic application to obtain an unstretched PET sheet. The unstretched PET sheet may have a single layer structure or a multilayer structure formed by coextrusion.

[0063] The resulting unstretched PET sheet is uniaxially or biaxially stretched to achieve crystal orientation. For example, in the case of biaxial stretching, the sheet is stretched 2.5 to 5.0 times in the machine direction using rolls heated to 80 to 120°C to obtain a uniaxially stretched PET film. The film is then gripped at its edges with clips and introduced into a hot air zone heated to 80 to 180°C, where it is stretched 2.5 to 5.0 times in the width direction. In the case of uniaxial stretching, the film is stretched 2.5 to 5.0 times in a tenter. After stretching, the film is subsequently introduced into a heat treatment zone where it is heat-treated to complete the crystal orientation.

[0064] The lower limit of the temperature in the heat treatment zone is preferably 170°C, more preferably 180°C. When the temperature in the heat treatment zone is 170°C or higher, sufficient curing is achieved, and blocking resistance in the presence of liquid water is favorable, which is preferable, and a long drying time is not required. On the other hand, the upper limit of the temperature in the heat treatment zone is preferably 230°C, more preferably 200°C. When the temperature in the heat treatment zone is 230°C or lower, there is no risk of deterioration in the physical properties of the film, which is preferable.

[0065] The coating layer can be provided after or during the film production process. From the viewpoint of productivity, it is particularly preferred to form the coating layer by applying a coating liquid to at least one surface of an unstretched or uniaxially stretched PET film at any stage of the film production process.

[0066] Any known method can be used to apply this coating solution to the PET film. Examples include reverse roll coating, gravure coating, kiss coating, die coating, roll brushing, spray coating, air knife coating, wire bar coating, pipe doctor coating, impregnation coating, and curtain coating. These methods can be used alone or in combination.

[0067] In the present invention, the thickness of the coating layer can be appropriately set within the range of 0.001 to 2.00 μm, but in order to achieve both processability and adhesiveness, it is preferably within the range of 0.01 to 1.00 μm, more preferably 0.02 to 0.80 μm, and even more preferably 0.05 to 0.50 μm. A coating layer thickness of 0.001 μm or more is preferable because it provides good adhesiveness. A coating layer thickness of 2.00 μm or less is preferable because it is less likely to cause blocking.

[0068] The upper limit of the haze of the highly adhesive polyester film of the present invention is preferably 1.5%, more preferably 1.3%, even more preferably 1.2%, and particularly preferably 1.0%. A haze of 1.5% or less is preferable in terms of transparency, and the film can be suitably used for optical films that require transparency.

[0069] (UV curing ink) In this invention, UV-curable ink is a general term for inks that cure under ultraviolet light. The ink contains pigments (dyes), oligomers and monomers, photopolymerization initiators and accelerators, and auxiliary agents. The oligomers and monomers act as fluid components within this composition, and after being spread on the substrate, they cure due to radicals generated from the photopolymerization initiator under a UV lamp. The proportions of oligomer and monomer species contained vary depending on the printing method, as described below. Essentially, no solvents are used except for viscosity adjustment purposes, and even if a solvent is used, it is preferable that it be at most about 10 parts by weight.

[0070] As the UV-curable ink in the present invention, light-resistant UV-curable ink and UV-curable screen ink are particularly preferably used.

[0071] (Light-resistant UV-curable ink) The light-resistant UV-curable ink of the present invention preferably contains an ultraviolet absorber. The ultraviolet absorber absorbs the irradiated ultraviolet light, thereby preventing deterioration of the coating film caused by ultraviolet light. The content of the ultraviolet absorber is preferably 0.5 to 10 parts by weight, more preferably 1 to 3 parts by weight, based on the total amount of ink. If the content of the ultraviolet absorber is less than 0.5%, the coating film tends to deteriorate after ultraviolet light irradiation, resulting in a decrease in lamination strength. If the content of the ultraviolet absorber is 10% by weight or more, the flexibility of the resin contained in the ink may be impaired, thereby hindering initial adhesion to the printed material. The ultraviolet absorber can be used alone or in combination of two or more types. The ultraviolet absorber may be any one of a benzotriazole-based ultraviolet absorber containing a benzotriazole skeleton having an ethylenically unsaturated bond, a benzophenone-based ultraviolet absorber containing a benzophenone skeleton, a salicylic acid-based ultraviolet absorber containing salicylic acid in its skeleton, a cyanoacrylate-based ultraviolet absorber containing a cyanoacrylate skeleton, a hindered phenol-based ultraviolet absorber containing a hindered phenol skeleton, and a triazine-based ultraviolet absorber containing a triazine skeleton, or two or more of these may be used in combination.

[0072] For example, there are cases where products packaged in laminates are stored under light exposure for long periods of time. Under these conditions, radicals are generated, which can reduce the cohesive strength or adhesive strength of the printing ink coating, resulting in a decrease in laminate strength. When a laminated product stored under light exposure for a long period of time is opened, there is a concern that delamination may occur between the layers, so light resistance is required.

[0073] (UV curable screen ink) The UV-curable screen ink of the present invention preferably contains an acrylic resin acrylate. The acrylic resin acrylate may have an acid value. Having an acid value can promote dispersibility with a colorant. As a result, clogging during screen printing can be prevented, and a printed layer with excellent design can be provided. From the viewpoint of improving pigment dispersibility, the acid value of the acrylic resin acrylate is preferably 10 mgKOH / g or more.

[0074] An example of a method for imparting an acid value to an acrylic resin acrylate is a method of copolymerizing a monomer having an acid value as a monomer. Examples of the monomer having an acid value include (meth)acrylic acid, maleic anhydride, 2-(meth)acryloyloxyethyl-succinic acid, 2-(meth)acryloyloxyethyl-hexahydrophthalic acid, 2-(meth)acryloyloxyethyl-phthalic acid, and 2-(meth)acryloyloxyethyl acid phosphate, and among these, (meth)acrylic acid is preferably used.

[0075] (screen printing) Screen printing is a type of stencil printing in which ink is placed on a perforated plate and then pushed to the other side using a spatula called a squeegee, applying the ink to the substrate. Compared to other printing methods, this method offers greater flexibility in the inks and substrates that can be printed. Another feature of screen printing is that it allows for a wider range of adjustments to the thickness of the ink when printed (printing film thickness) than other printing methods.

[0076] (Solvent-based ink) In this invention, solvent-based ink is a general term for ink that hardens by evaporation. It is an ink that contains pigment (dye), resin, diluting solvent, auxiliary agent, etc. After printing, the solvent evaporates rapidly, leaving the resin and pigment components to adhere to the printed surface. Because the drying speed is extremely fast, it is suitable for high-speed, high-volume printing.

[0077] Oxidative polymerization ink (oxidative polymerization ink) The oxidative polymerization ink in the present invention is composed mainly of drying oil that is polymerizable and hardens when exposed to oxygen in the air, and also contains pigments (dyes), polymerization accelerators, auxiliary agents, etc. The solvent 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-curable components and drying oil. The solvents mentioned above mainly refer to organic solvents, such as hydrocarbons like hexane and heptane, esters like ethyl acetate and ethyl acetate, and ketones like acetone and MEK. These can be used alone or in combination. Examples of organic solvents include mixtures with other solvents, and mixtures with alcohols. Polymerizable and curable 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.

[0078] (thermal transfer ink) The thermal transfer ink in this invention is a heat-melting pigment ink, and is used in the thermal transfer method, in which ink applied to an ink ribbon is melted by heat and transferred to paper for printing. The ink is composed of colorants such as pigments and dyes, binders such as wax and thermoplastic resins, and various additives such as softeners and dispersants. Resin and wax types of ink are used for the thermal transfer method. Resin types are particularly suitable for use in monochrome document output by word processors, tape writers, barcode printers, etc. In addition, by using a color ribbon, color printers can be used. It is also used in some printers and video printers.

[0079] (LBP toner) In this invention, LBP toner is a toner for coloring used in laser printers and copiers. It is a powder containing electrically charged particles (polymer resin), wax, pigments, etc. For color printing, four colors are used: blue-green, red-purple, yellow, and black. LBP is a page printer that uses a laser beam to charge the drum and then uses static electricity to attach the toner. [Example]

[0080] Next, the present invention will be described in detail using examples and experimental examples, but the present invention is not limited to the following examples.

[0081] [Production of Polyester Resin Pellets P-1] High-purity terephthalic acid and twice the molar amount of ethylene glycol were charged into a 2-liter stainless steel autoclave equipped with a stirrer, and 0.3 mol % of triethylamine was added to the acid component. The esterification reaction was carried out at 250°C under a pressure of 0.25 MPa while distilling off water from the system. The reaction yielded a mixture of bis(2-hydroxyethyl) terephthalate and oligomers (hereinafter referred to as the BHET mixture) with an esterification rate of approximately 95%. Next, while stirring this BHET mixture, an ethylene glycol solution of antimony trioxide was added as a polymerization catalyst so that the amount of antimony atoms was 0.04 mol % relative to the acid component in the polyester. The mixture was then stirred at 250°C under a nitrogen atmosphere and atmospheric pressure for 10 minutes. The temperature was then raised to 280°C over 60 minutes, while the pressure in the reaction system was gradually reduced to 13.3 Pa (0.1 Torr), and the mixture was further stirred for 2 minutes. The polycondensation reaction was carried out at 80°C and 13.3 Pa. After the pressure was released, the resin under slight pressure was discharged into cold water in the form of strands to be quenched, and then held in the cold water for 20 seconds, after which it was cut into cylindrical pellets with a length of approximately 3 mm and a diameter of approximately 2 mm.

[0082] The polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80°C, 12 hours), followed by crystallization (13.3 Pa or less, 130°C, 3 hours, and then 13.3 Pa or less, 160°C, 3 hours). After cooling, the polyester pellets were subjected to solid-state polymerization in a solid-state polymerization reactor while maintaining the system at 13.3 Pa or less and 215°C, yielding polyester pellets with an intrinsic viscosity of 0.62 dL / g.

[0083] [Production of Polyester Pellets P-2] (Preparation of Aluminum Compounds) It was prepared by heating at 80°C for 2 hours under stirring, and the peak position of the 27Al-NMR spectrum A 20 g / L aqueous solution of basic aluminum acetate (hydroxyaluminum diacetate; manufactured by Aldrich), which was confirmed to have undergone a chemical shift to a lower magnetic field, was charged into a flask together with an equal volume (volume ratio) of ethylene glycol. The mixture was stirred at room temperature for 6 hours, and then the mixture was stirred under reduced pressure (133 Pa) at 90-110°C for several hours while distilling off water from the system, to prepare a 20 g / L ethylene glycol solution of the aluminum compound.

[0084] (Preparation of phosphorus compounds) Irganox 1222 (manufactured by Ciba Specialty Chemicals) was used as a phosphorus compound. The mixture was charged into a flask together with glycol, and heated at a liquid temperature of 160°C for 25 hours while stirring under nitrogen purging to prepare a 50g / l ethylene glycol solution of the phosphorus compound. Torr measurement confirmed that about 60 mol % had been converted to hydroxyl groups. (Preparation of a mixture of aluminum compound in ethylene glycol and phosphorus compound in ethylene glycol) The ethylene glycol solutions obtained in the preparation of the aluminum compound and the preparation of the phosphorus compound were placed in a flask, mixed at room temperature so that the molar ratio of aluminum atoms to phosphorus atoms was 1:2, and stirred for one day to prepare a catalyst solution. Measurement of the 27Al-NMR spectrum and 31P-NMR spectrum of the mixed solution confirmed chemical shifts in both cases.

[0085] As a polycondensation catalyst, an ethylene glycol solution of the aluminum compound / a phosphorus compound The same procedure as in the production of polyester pellets P-1 was repeated, except that a mixture of aluminum and phosphorus was added in amounts of 0.014 mol % and 0.028 mol % of the acid component in the polyester, respectively, to obtain polyester pellets P-2 with an intrinsic viscosity of 0.65 dL / g.

[0086] (Polymerization of urethane resin A-1 having a polycarbonate structure) 32 parts by mass of 1,3-cyclohexyl diisocyanate, 7 parts by mass of dimethylolpropanoic acid, 58 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 800, 3 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added to a four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer, and the mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere. It was confirmed that the reaction solution had reached the required amine equivalent. Next, the reaction solution was cooled to 40°C, and 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred for 2000 min. -1 The polyurethane prepolymer solution was added to the mixture while stirring at 50°C, and dispersed in water. Then, the acetone and part of the water were removed under reduced pressure to prepare a water-dispersible urethane resin solution (A-1) with a solids content of 34%.

[0087] (Polymerization of urethane resin A-2 having a polycarbonate structure) 38 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 9 parts by mass of dimethylolpropanoic acid, 53 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 1000, and 84.00 parts by mass of acetone as a solvent were added to a four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer, and the mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere. It was confirmed that the reaction solution had reached the required amine equivalent. Next, the reaction solution was cooled to 40°C, and 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred for 2000 min. -1 The polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 50°C. Then, the acetone and part of the water were removed under reduced pressure to prepare a water-dispersible urethane resin solution (A-2) with a solids content of 35%.

[0088] (Polymerization of urethane resin A-3 having a polycarbonate structure) A four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer was charged with 30 parts by weight of 4,4-dicyclohexylmethane diisocyanate, 16 parts by weight of polyethylene glycol monomethyl ether having a number average molecular weight of 700, 50 parts by weight of polyhexamethylene carbonate diol having a number average molecular weight of 1200, 4 parts by weight of neopentyl glycol, and 84.00 parts by weight of acetone as a solvent. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution had reached the required amine equivalent. The reaction solution was then cooled to 40°C, yielding a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25°C, and the mixture was stirred for 2000 min. -1 The polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 50°C. Then, the acetone and part of the water were removed under reduced pressure to prepare a water-dispersible urethane resin solution (A-3) with a solids content of 35%.

[0089] (Polymerization of urethane resin A-4 having a polycarbonate structure) 24 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 4 parts by mass of dimethylol butanoic acid, 71 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2000, 1 part by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added to a four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution had reached the required amine equivalent. Next, the reaction solution was cooled to 40°C, and 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred for 2000 min. -1The polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 50°C. Then, the acetone and a portion of the water were removed under reduced pressure to prepare a water-dispersible urethane resin solution (A-4) with a solids content of 34% by mass.

[0090] (Polymerization of urethane resin A-5 not containing polycarbonate polyol component) Using a multi-stage isocyanate polyaddition method using polyether polyol, organic polyisocyanate, and diethylene glycol as a chain extender, the mixture was reacted at a temperature of 70 to 120°C for 2 hours. The resulting urethane prepolymer was mixed with an aqueous bisulfite solution and heated to about 100°C. The reaction was allowed to proceed for 1 hour with thorough stirring to form a block. The reaction temperature was set to 60° C. or lower. The mixture was then diluted with water to prepare a thermally reactive water-dispersible urethane resin solution (A-5) with a solids content of 20% by mass.

[0091] (Polymerization of urethane resin A-6 having a polycarbonate structure) A four-neck flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer was charged with 54 parts by weight of 4,4-dicyclohexylmethane diisocyanate, 16 parts by weight of polyethylene glycol monomethyl ether having a number average molecular weight of 700, 18 parts by weight of polyhexamethylene carbonate diol having a number average molecular weight of 1200, 12 parts by weight of neopentyl glycol, and 84.00 parts by weight of acetone as a solvent. The mixture was stirred at 75°C under a nitrogen atmosphere for 3 hours, and it was confirmed that the reaction solution had reached the required amine equivalent. Next, the reaction solution was cooled to 40°C, and 8.77 parts by weight of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred for 2000 min. -1 The polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 50°C. Then, the acetone and a portion of the water were removed under reduced pressure to prepare a water-dispersible urethane resin solution (A-6) with a solids content of 34% by mass.

[0092] The following two items are shown in Table 2. A. The mass ratio of the polycarbonate polyol component to the polyisocyanate component when synthesizing and polymerizing the urethane resin that forms the coating layer (polycarbonate polyol component / polyisocyanate component) B. Molecular weight of polycarbonate polyol component

[0093] [Table 2]

[0094] (Polymerization of blocked isocyanate crosslinking agent B-1) A flask equipped with a stirrer, thermometer, and reflux condenser was charged with 66.04 parts by weight of a polyisocyanate compound (Duranate TPA, manufactured by Asahi Kasei Chemicals) having an isocyanurate structure derived from hexamethylene diisocyanate, 17.50 parts by weight of N-methylpyrrolidone, and 25.19 parts by weight of 3,5-dimethylpyrazole (dissociation temperature: 120°C, boiling point: 218°C). The mixture was then maintained at 70°C for 1 hour under a nitrogen atmosphere. Subsequently, 5.27 parts by weight of dimethylolpropanoic acid was added dropwise. The infrared spectrum of the reaction solution was measured, and after confirming that the absorption of the isocyanate group had disappeared, 5.59 parts by weight of N,N-dimethylethanolamine and 132.5 parts by weight of water were added to obtain a blocked polyisocyanate aqueous dispersion (B-1) with a solids content of 40% by weight. The blocked isocyanate crosslinker had four functional groups.

[0095] (Polymerization of blocked isocyanate crosslinking agent B-2) A flask equipped with a stirrer, thermometer, and reflux condenser was charged with 100 parts by weight of a polyisocyanate compound having an isocyanurate structure (Duranate TPA, manufactured by Asahi Kasei Chemicals), 55 parts by weight of propylene glycol monomethyl ether acetate, and 30 parts by weight of polyethylene glycol monomethyl ether (average molecular weight 750). The mixture was then maintained at 70°C for 4 hours under a nitrogen atmosphere. The reaction mixture temperature was then lowered to 50°C, and 47 parts by weight of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction mixture was measured to confirm that the absorption of the isocyanate group had disappeared, yielding an oxime-blocked isocyanate crosslinking agent (B-2) with a solids content of 40% by weight. The number of functional groups in the blocked isocyanate crosslinking agent was 3.

[0096] (Polymerization of carbodiimide B-3) A flask equipped with a stirrer, thermometer, and reflux condenser was charged with 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400), and the mixture was stirred at 120°C for 1 hour. 26 parts by mass of 4,4'-dicyclohexylmethane diisocyanate and 3.8 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide (2% by mass relative to the total isocyanate) were then added as a carbodiimide catalyst, and the mixture was stirred at 185°C for an additional 5 hours under a nitrogen stream. The infrared spectrum of the reaction solution was measured at a wavelength of 220 to 2300 cm. -1 It was confirmed that the absorption of 100% by mass had disappeared. The mixture was allowed to cool to 60° C., and 567 parts by mass of ion-exchanged water was added to obtain a carbodiimide aqueous resin liquid (B-3) with a solid content of 40% by mass.

[0097] (Polymerization of Polyester Resin C-1) A stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser was charged with 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, 185 parts by mass of neopentyl glycol, 188 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate, and a transesterification reaction was carried out at a temperature of 160 to 220°C for 4 hours. The temperature was then raised to 255°C, and the reaction system was gradually reduced in pressure. The reaction was then continued for 1 hour and 30 minutes under a reduced pressure of 30 Pa to obtain copolymer polyester resin (C-1). The resulting copolymer polyester resin (C-1) was pale yellow and transparent. The reduced viscosity of copolymer polyester resin (C-3) was measured and found to be 0.40 dL / g. The glass transition temperature measured by DSC was 65°C.

[0098] (Preparation of Polyester Water Dispersion Cw-1) A reactor equipped with a stirrer, thermometer, and reflux device was charged with 25 parts by mass of polyester resin (C-1) and 10 parts by mass of ethylene glycol n-butyl ether, and the mixture was heated to 110°C and stirred to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the liquid was cooled to room temperature while stirring to produce a milky white polyester water dispersion (Cw-1) with a solids content of 25% by mass.

[0099] Example 1 (1) Preparation of coating solution The following coating agent was mixed with a mixed solvent of water and isopropanol to prepare a coating solution with a solids mass ratio of urethane resin solution (A-1) / crosslinking agent (B-1) / polyester water dispersion (Cw-1) of 25 / 26 / 49. Urethane resin solution (A-1) 3.55 parts by mass Crosslinking agent (B-1) 3.16 parts by mass Polyester water dispersion (Cw-1) 16.05 parts by mass Particles 0.47 parts by mass (Dry process silica with an average particle size of 200 nm, solid content 3.5%) Particles 1.85 parts by mass (Silica sol with an average particle size of 40 to 50 nm, solid content concentration of 30% by mass) Surfactant 0.30 parts by mass (Silicone-based, solid content 10% by mass)

[0100] (2) Manufacturing of highly adhesive polyester film Polyester pellets P-1, used as the raw polymer for the film, were dried at 135°C for 6 hours under a reduced pressure of 133 Pa. Then, the pellets were fed into an extruder and melt-extruded into a sheet at approximately 280°C. The extruded material was rapidly cooled and solidified on a rotating cooling metal roll maintained at a surface temperature of 20°C to obtain an unstretched PET sheet.

[0101] This unstretched PET sheet was heated to 100° C. using a group of heated rolls and an infrared heater, and then stretched 3.5 times in the longitudinal direction using a group of rolls with different peripheral speeds to obtain a uniaxially stretched PET film.

[0102] Next, the coating solution, which had been left to stand at room temperature for 5 hours or more, was applied to one side of a PET film by a roll coating method, and then dried at 80°C for 20 seconds. The final coating amount after drying (after biaxial stretching) was 0.15 g / m 2 The film was then stretched 4.0 times in the width direction at 120°C in a tenter, and while the length of the film in the width direction was fixed, it was heated at 230°C for 5 seconds, and further subjected to a 3% width direction relaxation treatment at 100°C for 10 seconds to obtain a 100µm highly adhesive polyester film.

[0103] (3) Production of printed materials (Printed matter with UV-curable ink layer (1): low dose) The coating layer of the highly adhesive polyester film was printed using a printing machine (manufactured by Akira Manufacturing Co., Ltd., product name "RI Tester") with a light-resistant UV-curable ink of the following composition. Then, 30 seconds after printing, a high-pressure mercury lamp was used to irradiate the film with the ink layer with an integrated light dose of 40 mJ. / cm 2The UV-curable offset ink was cured by irradiation with ultraviolet light, and a printed matter (1) having a light-resistant UV-curable ink layer was obtained. (Light-resistant UV-curable ink) Manufactured by T&K TOKA Co., Ltd., product name: "BEST CURE (registered trademark) UV161 Indigo S" 1 00 parts by mass Benzophenone-based UV absorber (Chemisorb 11, manufactured by Chemipro Chemicals) 4 parts by mass

[0104] (Printed matter with UV-curable ink layer (2): Screen printing) On the coating layer of the highly adhesive polyester film, a UV-curable screen ink (manufactured by TOYOINK Corporation, product name "TU240 FDSS 911 Black") was applied to a Tetron screen (#25 Then, a high-pressure mercury lamp was used to illuminate the ink-coated film. 500mJ / cm 2 UV curing screen ink is cured by irradiating it with UV rays. A printed matter (2) having a V-curable screen ink layer was obtained.

[0105] (Printed matter with UV-curable ink layer (3): High-speed printing) The coating layer of the highly adhesive polyester film was printed on with a central impression printer using a light-resistant UV-curable ink of the following composition. 3 / m 2 After measuring the ink with an anilox roll, it was transferred to a solid plate and then to a film. The ink transferred to the film was cured with a 160W / cm metal halide UV lamp. The ink was transferred onto the film to obtain a printed matter (3) with a light-resistant UV-curable ink layer. The time from the start of irradiation to UV light was 0.94 seconds. (Light-resistant UV-curable ink) Manufactured by T&K TOKA Co., Ltd., product name: “BEST CURE (registered trademark) UV161 Indigo S” 100 parts by mass Benzophenone-based UV absorber (Chemisorb 11, manufactured by Chemipro Chemicals) 4 parts by mass

[0106] (Printed matter with a solvent-based ink layer) On the coated layer of the highly adhesive polyester film, a solvent-based ink [Jujo Ink Co., Ltd., 900 Series Tetron Ink] was used to screen the film with a Tetron screen (#250 mesh). After printing, the film on which the ink layer was applied was left to dry for 24 hours, and a printed matter having a solvent-based ink layer was obtained.

[0107] (Printed matter with an oxidative polymerization ink layer) Oxidative polymerization ink (Jujo Kako Co., Ltd., black) was diluted with a dilution solvent (Jujo Kako Co., Ltd., Dilute the ink with diluting solvent at a volume ratio of 4:1 and apply it to the film surface ( If a coating layer is provided, print on the surface of the coating layer using a Tetron screen (# 250 mesh), leave it to dry for 24 hours, and then print with an oxidative polymerization type ink layer. obtained.

[0108] (Printed matter with a thermal transfer ink layer) A thermal transfer ribbon (Ricoh Co., Ltd., B-110C resin type, black) was attached to a Bon Electric Co., Ltd. BLP-323, and a barcode pattern created arbitrarily was printed on the coating layer of the highly adhesive polyester film, resulting in a printed material with a thermal transfer ink layer.

[0109] (Printed matter with LBP toner layer) FUJI XEROX Corporation ApeosPort-V C3376 is used to apply highly adhesive polyester film. A design created arbitrarily was printed on the layer to obtain a printed matter having an LBP toner layer. The evaluation results are shown in Table 5.

[0110] Example 2 An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the urethane resin was changed to (A-2).

[0111] Example 3 An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the urethane resin was changed to (A-3).

[0112] Example 4 An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the crosslinking agent was changed to (B-2).

[0113] Example 5 The following coating agent was mixed into a mixed solvent of water and isopropanol, and an easily adhesive polyester film and printed matter were obtained in the same manner as in Example 1, except that the solid mass ratio of urethane resin solution (A-1) / crosslinking agent (B-1) / polyester water dispersion (Cw-1) was changed to 22 / 10 / 68. Urethane resin solution (A-1) 2.71 parts by mass Crosslinking agent (B-1) 1.00 parts by mass Polyester water dispersion (Cw-1) 19.05 parts by mass Particles 0.47 parts by mass (Dry process silica with an average particle size of 200 nm, solid content 3.5%) Particles 1.85 parts by mass (Silica sol with an average particle size of 40 to 50 nm, solid content concentration of 30% by mass) Surfactant 0.30 parts by mass (Silicone-based, solid content 10% by mass)

[0114] Example 6 An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 5, except that the urethane resin was changed to (A-2).

[0115] As shown in Table 5, in Examples 1 to 6, "BA," "b," and "cb" each satisfied the ranges of the following formulas, and the haze and blocking resistance were satisfactory. (i) 0.5 ≦ BA(at%) ≦ 3.0 (ii) 30 ≦ b(seconds) ≦ 180 (iii) 30 ≦ cb(sec) ≦ 300 In addition, "X" satisfied the following formula, demonstrating satisfactory adhesion to each ink layer. Furthermore, it was found that the adhesiveness to UV-curable inks was also excellent during low-dose processing and high-speed printing. (iv) 2.0≦X(%)≦10.0

[0116] Example 7 An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the polyester pellets (P-2) were used as the raw polymer for the film.

[0117] As shown in Table 5, in Example 7, "BA," "b," and "cb" each satisfied the ranges of the following formulas, and the blocking resistance was satisfactory. (i) 0.5 ≦ BA(at%) ≦ 3.0 (ii) 30 ≦ b(seconds) ≦ 180 (iii) 30 ≦ cb(sec) ≦ 300 In addition, "X" satisfied the following formula, demonstrating satisfactory adhesion to each ink layer. Furthermore, it was found that the adhesiveness to UV-curable inks was also excellent, particularly during low-dose processing and high-speed printing. (iv) 2.0≦X(%)≦10.0 Furthermore, it was confirmed that the haze value was smaller than that of Examples 1 to 6 in which polyester pellets P-1 were used, and the transparency of the film was improved.

[0118] (Experimental Example 1) The following coating agent was mixed into a mixed solvent of water and isopropanol, and an easily adhesive polyester film and printed matter were obtained in the same manner as in Example 1, except that the solids ratio of the urethane resin solution (A-5) / polyester water dispersion (Cw-1) was changed to 29 / 71. Urethane resin solution (A-5) 6.25 parts by mass Polyester water dispersion (Cw-1) 20.00 parts by mass Elastron catalyst 0.50 parts by mass Particles 1.02 parts by mass (Dry process silica with an average particle size of 200 nm, solid content 3.5%) Particles 2.15 parts by mass (Silica sol with an average particle size of 40 nm, solid content of 20% by mass) Surfactant 0.30 parts by mass (Fluorine-based, solids concentration 10% by mass)

[0119] As shown in Table 5, in Experimental Example 1, "X" was less than 2.0%, so the adhesion to each ink layer was unsatisfactory. Also, "b" exceeded 180 seconds, so the blocking resistance was also unsatisfactory.

[0120] (Experimental Example 2) An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the urethane resin was changed to (A-4).

[0121] (Experimental Example 3) An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 1, except that the urethane resin was changed to (A-4) and the crosslinking agent was changed to (B-2).

[0122] As shown in Table 5, in Experimental Examples 2 and 3, the "BA" content was less than 0.5 at %, and therefore the adhesion to the solvent-based ink layer was not satisfactory.

[0123] (Experimental Example 4) The following coating agent was mixed into a mixed solvent of water and isopropanol, and an easily adhesive polyester film and printed matter were obtained in the same manner as in Example 1, except that the solids ratio of urethane resin solution (A-4) / crosslinking agent (B-1) was changed to 70 / 30. Urethane resin solution (A-4) 9.03 parts by mass Crosslinking agent (B-1) 3.38 parts by mass Particles 0.52 parts by mass (Dry process silica with an average particle size of 200 nm, solid content 3.5%) Particles 1.80 parts by mass (Silica sol with an average particle size of 40 nm, solid content of 30% by mass) Surfactant 0.30 parts by mass (Silicone-based, solid content 10% by mass)

[0124] As shown in Table 5, in Experimental Example 4, the haze was not satisfactory because "cb" exceeded 300 seconds.

[0125] (Experimental Example 5) The following coating agent was mixed into a mixed solvent of water and isopropanol, and an easily adhesive polyester film and printed matter were obtained in the same manner as in Example 1, except that the solids ratio of urethane resin solution (A-4) / crosslinking agent (B-1) was changed to 20 / 80. Urethane resin solution (A-4) 2.58 parts by mass Crosslinking agent (B-1) 9.00 parts by mass Particles 0.52 parts by mass (Dry process silica with an average particle size of 200 nm, solid content 3.5%) Particles 1.80 parts by mass (Silica sol with an average particle size of 40 nm, solid content of 30% by mass) Surfactant 0.30 parts by mass (Silicone-based, solid content 10% by mass)

[0126] As shown in Table 5, in Experimental Example 5, the haze was not satisfactory because "cb" exceeded 300 seconds.

[0127] (Experimental Example 6) An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 5, except that the urethane resin was changed to (A-2) and the crosslinking agent was changed to (B-3).

[0128] As shown in Table 5, in Experimental Example 6, the "BA" content was less than 0.5 at %, and therefore the blocking resistance and adhesion to the solvent-based ink layer were not satisfactory.

[0129] (Experimental Example 7) An easily adhesive polyester film and a printed matter were obtained in the same manner as in Example 5, except that the urethane resin was changed to (A-6).

[0130] As shown in Table 5, in Experimental Example 7, "X" was less than 2.0%, and therefore the adhesion to each ink layer was not satisfactory.

[0131] The evaluation methods used in the present invention will be explained below.

[0132] (1) Hayes The haze of the obtained highly adhesive polyester film was measured in accordance with JIS K 7136:2000 using a turbidity meter (NDH5000, manufactured by Nippon Denshoku Corporation).

[0133] (2) Blocking resistance Two film samples were placed together with the coating surfaces facing each other, and a load of 98 kPa was applied. The samples were then left in close contact for 24 hours in an atmosphere at 50° C. The films were then peeled off, and the peeling condition was evaluated according to the following criteria. ◯: The coating layer was not transferred and could be easily peeled off. △: The coating layer is maintained, but the surface layer of the coating layer is partially transferred to the opposing surface. ×: The two films were stuck together and could not be separated, or even if they could be separated, the film substrate was cleaved.

[0134] (3) Adhesion Using a cutter guide with a gap of 2 mm, 100 grid-shaped cuts were made in the ink layer of the resulting print, penetrating the ink layer and reaching the base film. Next, cellophane adhesive tape (Nichiban Co., Ltd., No. 405; 24 mm wide) was applied to the grid-shaped cuts and rubbed with an eraser to ensure complete adhesion. The cellophane adhesive tape was then peeled vertically five times from the ink layer surface of the highly adhesive polyester film on which the ink layer was laminated. The number of squares that peeled from the ink layer surface of the print was visually counted, and the adhesion between the ink layer and the film base was calculated using the following formula. Note that partially peeled squares were also counted as peeled squares. An adhesion of 95% or higher was considered acceptable. Adhesion (%) = (1 - number of peeled squares / 100) x 100

[0135] (4) Measurement of elemental distribution in the depth direction The elemental distribution in the depth direction of the coating layer was measured using X-ray photoelectron spectroscopy (ESCA). The etching ion source used was an Ar cluster, which is expected to cause less damage to organic materials. The sample was rotated during etching to ensure uniform etching. To minimize damage from X-ray irradiation, spectra were collected at each etching time in snapshot mode, which allows for quick evaluation. For evaluation purposes, spectra were collected every 30 seconds until the etching time was 120 seconds, and every 60 seconds thereafter. Details of the measurement conditions are shown below. During analysis, background removal was performed using the Shirley method. ·Equipment: K-Alpha + (Thermo Fisher Scientific) Measurement conditions Excitation X-ray: Monochromated Al Kα line X-ray output: 12 kV, 2.5 mA Photoelectron escape angle: 90° Spot size: 200 μmφ Pass energy: 150 eV (Snapshot mode) Ion gun acceleration voltage: 6kV Cluster size: Large Etching rate: 10 nm / min (polystyrene equivalent) ※ Sample rotation during etching: Yes (To calculate the etching rate, monodisperse polystyrene with a molecular weight Mn of 91,000 (Mw / Mn = 1.05) was dissolved in toluene and then spin-coated onto a silicon wafer to form a 155 nm thick film.)

[0136] Based on the data thus evaluated, a nitrogen distribution curve was plotted, with the horizontal axis representing the etching time from the coating layer surface and the vertical axis representing the ratio of the amount of nitrogen atoms to the total amount of carbon, oxygen, nitrogen, and silicon atoms (nitrogen atomic ratio). The nitrogen distribution curves for the highly adhesive polyester film samples (Examples 2, 5, and Experimental Example 6) described below are shown in Figures 1, 3, and 4, respectively. The method for determining the characteristic values ​​of the present invention based on the nitrogen distribution curve of Example 2 shown in Figure 1 is explained using Figure 2. As shown in Figure 2, the nitrogen atomic ratio on the coating layer surface opposite the polyester film substrate is A (at%), the maximum nitrogen atomic ratio is B (at%), the etching time at which the nitrogen atomic ratio reaches the maximum value B (at%) is b (seconds), and the etching time at which the nitrogen atomic ratio reaches 1 / 2B (at%) after b (seconds) is c (seconds), and B (at%) and cb (seconds) are calculated to determine the nitrogen atomic ratio. The nitrogen atomic ratio on the coating layer surface opposite the polyester film substrate refers to the nitrogen atomic ratio at an etching time of 0 (seconds) in the figure. (Note that the "etching time s" on the horizontal axis in Figures 1 to 4 means the unit "seconds.")

[0137] (5) Measurement of the OCOO bond ratio in the surface area The ratio of OCOO bonds (X) in the surface area was evaluated by X-ray photoelectron spectroscopy (ESCA). K-Alpha + (Thermo Fisher Scientific) was used. Details of the measurement conditions are as follows: During the analysis, background was removed using the Shirley method. X was calculated as the average value of measurements at three or more locations. Measurement conditions Excitation X-ray: Monochromated Al Kα line X-ray output: 12 kV, 6 mA Photoelectron escape angle: 90° Spot size: 400 μmφ Pass energy: 50eV Step: 0.1eV Energy resolution: FWHM of Ag3d(5 / 2) spectrum = 0.75 eV 5 and 6 are graphs showing the analysis results of the C1s spectra of the surface regions of the highly adhesive polyester films of Example 6 and Experimental Example 1, respectively. The gray solid line represents the measured C1s spectrum data. The peaks of the measured spectra were separated into multiple peaks, and the bond species corresponding to each peak was identified from the peak position and shape. Furthermore, curve fitting was performed on the peaks derived from each bond species, and the peak area was calculated. The bond species of each peak (1) to (6) that may appear are shown in Table 3.

[0138] [Table 3]

[0139] The total peak area derived from each bond in the C1s spectral region refers to the total peak area of ​​peaks (1) to (6), and the peak area derived from the OCOO bond refers to the total peak area of ​​peak (5). When the total peak area of ​​each bond species in the C1s spectral region is taken as 100%, X (%) represents the percentage of the area of ​​peak (5).

[0140] Table 4 shows the results of calculating the peak areas of peaks (1) to (6) in Example 6 and Experimental Example 1. As mentioned above, the percentage data for peak (5) is the data for X (%). Peaks (3) and (6) in Example 6 and peaks (3) and (5) in Experimental Example 1 did not appear.

[0141] [Table 4]

[0142] (6) Method for measuring number average molecular weight of polycarbonate polyol When urethane resins with polycarbonate structures are measured by proton nuclear magnetic resonance spectroscopy (H-NMR), a peak derived from the methylene group adjacent to the OCOO bond is observed at around 4.1 ppm. Additionally, a peak derived from the methylene group adjacent to the urethane bond formed by the reaction of polyisocyanate with polycarbonate polyol is observed approximately 0.2 ppm higher than this peak. The number-average molecular weight of the polycarbonate polyol was calculated from the integral values ​​of these two peaks and the molecular weight of the monomers that make up the polycarbonate polyol.

[0143] Table 5 summarizes the evaluation results of each example and experimental example.

[0144] [Table 5] [Industrial Applicability]

[0145] The highly adhesive polyester film of the present invention has excellent adhesion to UV-curable inks, solvent-based inks, oxidative polymerization inks, thermal transfer ink ribbons, and LBP toners, and is particularly suitable as a base film for a wide variety of printed materials, as it has good adhesion to UV-curable inks during low-dose processing or high-speed printing.

Claims

1. A printed matter comprising a polyester film substrate having a coating layer on at least one surface thereof, and at least one ink layer selected from a UV-curable ink, a solvent-based ink, an oxidative polymerization ink, a thermal transfer ink ribbon, and an LBP toner laminated on the coating layer, the coating layer is formed by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin, The urethane resin having a polycarbonate structure is a resin synthesized and polymerized containing a polycarbonate polyol component and a polyisocyanate component, the mass ratio of the polycarbonate polyol component to the polyisocyanate component is within the range of 0.5 to 2.5; the content of the solid content of the crosslinking agent is 10 to 50 mass % when the total solid content of the polyester resin, the urethane resin, and the crosslinking agent in the coating liquid is 100 mass %; The crosslinking agent contains a blocked isocyanate having a tri- or higher functional isocyanate group, In the nitrogen element distribution curve based on the element distribution measurement in the depth direction of the coating layer by X-ray photoelectron spectroscopy, the nitrogen atomic ratio on the surface of the coating layer opposite to the polyester film substrate is A (at%), the maximum value of the nitrogen atomic ratio is B (at%), and the nitrogen atomic ratio is the maximum value B (at%). is defined as b (seconds), and the etching time when the nitrogen atomic ratio becomes 1 / 2B (at%) after b (seconds) is defined as c (seconds). The following formulae (i) to (iii) are satisfied, and in a surface analysis spectrum measured by X-ray photoelectron spectroscopy, when the total area of ​​the peaks attributable to each bond type in the C1s spectrum region is taken as 100 (%) and the peak area attributable to the OCOO bond is taken as X (%), the following formula (iv) is satisfied: Printed matter; (i) 0.5 ≦ B-A (at%) ≦ 3.0 (ii) 30 ≦ b (seconds) ≦ 180 (iii) 30 ≦ c-b (seconds) ≦ 300 (iv) 2.0≦X(%)≦10.0

2. A printed matter, wherein the highly adhesive polyester film according to claim 1 has a haze of 1.5% or less.

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