printed matter

Abstract

Provided is a printed matter using an easily-adhesive polyester film that has high transparency and has blocking resistance, and has good adhesion to various ink compositions, particularly good adhesion to a UV-curable ink even when processed at a low radiation dose or when printed at high speed. A printed matter having specific properties, in which at least one face of a polyester film substrate has an easily-adhesive polyester film in which a coating layer containing a composition of a polyurethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin is cured, and at least one ink layer selected from a UV-curable ink, a solvent-based ink, an oxidation-polymerization-based ink, a thermal transfer ink ribbon, and an LBP toner is layered on the aforementioned coating layer.

Description

Technical Field

[0001] This invention relates to printed materials with excellent adhesion to various ink layers. More specifically, it relates to printed materials with coatings having easy adhesion to all types of ink layers, including ultraviolet (UV) curable inks, solvent-based inks, oxidative polymer inks, heat transfer ink ribbons, LBP toners, etc. Background Technology

[0002] Biaxially stretched polyester film is widely used in various industrial and civilian applications due to its mechanical strength, heat resistance, chemical resistance, dimensional stability, and price balance. It is indispensable, especially in commercial printing applications such as printing on transparent films, decorative panels, packaging cans, and labels. However, polyester films typically have poor adhesion to printing inks, therefore, anchoring coatings with easily adhesive resins are often used. For relatively high-polarity films primarily composed of polyester, solutions using water-soluble or water-dispersible polyester resins and acrylic resins have been proposed (see, for example, Patent Documents 1, 2, 3, and 4). However, the aforementioned polyester resins suffer from poor anti-blocking properties in the film roll state, and the aforementioned acrylic resins have poor adhesion to both the base film and the printing ink. Therefore, to improve these issues, a mixture of the aforementioned polyester resins and acrylic resins has been proposed (see, for example, Patent Document 5), but the improvement in these drawbacks is not considered sufficient. Furthermore, solutions using various modified polyesters, primarily through grafting modification, have been proposed. Furthermore, it has been disclosed that resins obtained by grafting compounds containing unsaturated bonds onto polyester resins containing hydrophilic groups that can be water-soluble or water-dispersible are suitable as anchoring agents for polyester films (see, for example, Patent Documents 6, 7, and 8). However, their performance in terms of adhesion and water resistance is not yet sufficient. Moreover, although graft-modified resins of polyester have been disclosed (see, for example, Patent Documents 9 and 10), problems such as peeling and scratching remain due to a lack of cohesive strength.

[0003] These problems are associated with fatal defects in printing applications, such as scratches, coating / lubricant particle detachment, and poor ink transfer / peeling. They are particularly essential in sheet metal offset printing applications due to the intense friction during paper feeding / transfer and the requirement for high adhesion caused by UV-curable inks.

[0004] In recent years, the printing industry has driven the pursuit of higher printing speeds to increase productivity. In high-speed printing using UV-curable inks, the time required from ink application to UV irradiation and the cumulative UV light intensity have decreased. This means the interaction between the ink and the polyester film, as well as with the coating layer, has weakened. Therefore, a higher degree of adhesion between the coating layer and the UV-curable ink is required.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 54-43017

[0008] Patent Document 2: Japanese Patent Publication No. 49-10243

[0009] Patent Document 3: Japanese Patent Application Publication No. 52-19786

[0010] Patent Document 4: Japanese Patent Application Publication No. 52-19787

[0011] Patent Document 5: Japanese Patent Application Publication No. 58-124651

[0012] Patent Document 6: Japanese Patent Application Publication No. 2-3307

[0013] Patent Document 7: Japanese Patent Application Publication No. 2-171243

[0014] Patent Document 8: Japanese Patent Application Publication No. 2-310048

[0015] Patent Document 9: Japanese Patent Application Publication No. 3-273015

[0016] Patent Document 10: Japanese Patent Application Publication No. 3-67626 Summary of the Invention

[0017] The problem the invention aims to solve

[0018] This invention was made against the backdrop of the aforementioned prior art issues. Specifically, the object of this invention is to provide a printed material that uses an easily bondable polyester film. This easily bondable polyester film has high transparency and anti-blocking properties, exhibiting good adhesion to various ink compositions, particularly under low-radiation-dose processing or high-speed printing, with good adhesion to various ink compositions, such as UV-curable inks.

[0019] Solution for solving the problem

[0020] In order to solve the above-mentioned problems, the inventors discovered during their research on the causes of the problems that when a coating layer is provided on at least one side of a polyester film substrate, the coating layer comprising a crosslinking agent, a polyurethane resin having a polycarbonate structure, and a polyester resin, and the ratio of nitrogen atoms in the coating layer and the ratio of OCOO bonds on the surface of the coating layer opposite to the polyester film substrate satisfies specific conditions, the problems of the present invention can be solved, and thus the present invention is completed.

[0021] The aforementioned issues can be addressed through the following solutions.

[0022] 1. A printed material comprising at least one ink layer selected from UV-curable inks, solvent-based inks, oxidative polymeric inks, heat transfer ink ribbons, and LBP toner, laminated on a coating layer of an easily adhesive polyester film having a coating layer on at least one side of a polyester film substrate.

[0023] The coating layer is formed by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin.

[0024] In the nitrogen element distribution curve determined by X-ray photoelectron spectroscopy based on the depth direction elemental distribution of the coating layer, when the nitrogen atom ratio on the coating layer surface opposite to the polyester film substrate is set to A (at%), the maximum value of the nitrogen atom ratio is set to B (at%), the etching time at which the nitrogen atom ratio shows the maximum value B (at%) is set to b (seconds), and the etching time when the nitrogen atom ratio becomes 1 / 2B (at%) after b (seconds) is set to c (seconds), the following equations (i) to (iii) are satisfied. Furthermore, in the surface analysis spectrum determined by X-ray photoelectron spectroscopy, when the total peak area originating from each bond type in the C1s spectral region is set to 100 (%) and the peak area originating from the OCOO bond is set to X (%), the following equation (iv) is satisfied.

[0025] (i) 0.5 ≤ BA(at%) ≤ 3.0

[0026] (ii) 30 ≤ b (seconds) ≤ 180

[0027] (iii) 30 ≤ cb (seconds) ≤ 300

[0028] (iv)2.0≤X(%)≤10.0.

[0029] 2. The printed material according to the first description above has a haze of less than 1.5% for its easy-to-adhere polyester film.

[0030] The effects of the invention

[0031] According to the present invention, various printed materials with good adhesion between the substrate and the ink layer can be obtained. Especially during low-radiation-dose processing or high-speed printing, excellent adhesion is achieved with various ink compositions, such as UV-curable inks. Furthermore, the easy-to-bond polyester film of the present invention exhibits high transparency and excellent anti-blocking properties. Attached Figure Description

[0032] Figure 1 This is a nitrogen distribution curve based on the depth-direction elemental distribution determination using X-ray photoelectron spectroscopy for the easily bondable polyester film of Example 2.

[0033] Figure 2 This is an explanatory diagram used to determine BA, b, and cb from the nitrogen element distribution curve determined based on the depth-direction elemental distribution using X-ray photoelectron spectroscopy.

[0034] Figure 3 This is a nitrogen distribution curve based on the depth-direction elemental distribution determination using X-ray photoelectron spectroscopy for the easily bondable polyester film of Example 5.

[0035] Figure 4 This is a nitrogen distribution curve based on the depth-direction elemental distribution determination using X-ray photoelectron spectroscopy for the easily bondable polyester film of Experimental Example 6.

[0036] Figure 5 This is a graph showing the analytical results of the C1s spectrum of the surface region of the coating layer of the easy-to-adhere polyester film of Example 6.

[0037] Figure 6 This is a graph showing the analytical results of the C1s spectrum of the surface region of the coating layer of the easily bondable polyester film of Experimental Example 1. Detailed Implementation

[0038] (Polyester film substrate)

[0039] In this invention, the polyester resin constituting the polyester film substrate is, in addition to polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, and polypropylene terephthalate, a copolymer polyester resin in which a portion of the diol or dicarboxylic acid component of the aforementioned polyester resin is replaced with a copolymer component such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, polyalkylene glycol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, sodium 5-isophthalate, and 2,6-naphthalenedicarboxylic acid.

[0040] The polyester resins suitable for use in this invention are mainly selected from polyethylene terephthalate, polyethylene terephthalate, polyethylene butylene terephthalate, and polyethylene 2,6-naphthalate. Among these polyester resins, polyethylene terephthalate is the most preferred considering the balance between physical properties and cost. Furthermore, the polyester film substrate made of these polyester resins is preferably a biaxially stretched polyester film, which can improve chemical resistance, heat resistance, and mechanical strength.

[0041] The catalyst used for polycondensation in the manufacture of polyester resin is not particularly limited, but antimony trioxide is preferred because it is inexpensive and has excellent catalytic activity. Germanium compounds or titanium compounds are also preferred. Further preferred polycondensation catalysts include catalysts containing aluminum and / or its compounds and phenolic compounds, catalysts containing aluminum and / or its compounds and phosphorus compounds, and catalysts containing aluminum salts of phosphorus compounds.

[0042] In addition, the polyester film substrate in this invention can be a single-layer polyester film, can be composed of two layers with different compositions, or can be a polyester film substrate composed of at least three layers with an outer layer and an inner layer.

[0043] (Explanation of characteristic values ​​in this invention)

[0044] The easily adhesive polyester film of the present invention is preferably one that has a coating layer on at least one side of the polyester film substrate, as described above. The aforementioned coating layer is formed by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin. Here, the phrase "formed by curing a composition" is used because it is extremely difficult to accurately describe the chemical composition of the polyurethane resin having a polycarbonate structure, the crosslinking agent, and the polyester resin in a cured state where a crosslinked structure is formed by the crosslinking agent. Furthermore, it is preferable that the maximum value of the nitrogen element distribution curve in the depth direction of the aforementioned coating layer, based on elemental distribution measurements, exists near the surface of the coating layer on the opposite side of the polyester film substrate, thereby improving transparency and anti-adhesion properties. Moreover, it is preferable that an appropriate amount of polycarbonate structure exists on the surface of the coating layer on the opposite side of the polyester film substrate, thereby improving UV ink adhesion during low-radiation-dose processing and high-speed printing.

[0045] The characteristics of the coating layer in the aforementioned easily bondable polyester film are explained. First, the nitrogen element distribution curve of the coating layer, determined based on the depth direction, was plotted using X-ray photoelectron spectroscopy (ESCA). Specifically, the spectrum was collected every 30 seconds until the etching time reached 120 seconds, and then every 60 seconds thereafter. Furthermore, as... Figure 2As shown, the etching time (in seconds) of the coating layer surface is set as the horizontal axis, and the ratio of nitrogen atoms to the total amount of carbon, oxygen, nitrogen, and silicon atoms (nitrogen atom ratio, in at%) is set as the vertical axis. The nitrogen atom ratio of the coating layer surface on the opposite side of the polyester film substrate is set as A (at%), the maximum nitrogen atom ratio is set as B (at%), the etching time when the nitrogen atom ratio reaches the maximum value B (at%) is set as b (seconds), and the etching time when the nitrogen atom ratio becomes 1 / 2 B (at%) after b (seconds) is set as c (seconds). BA (at%) and cb (seconds) are calculated from the read data. The nitrogen atom ratio A (at%) of the coating layer surface on the opposite side of the polyester film substrate is the nitrogen atom ratio at etching time 0 (seconds).

[0046] Furthermore, when the characteristic values ​​read from the nitrogen element distribution curve determined by the depth-direction elemental distribution of the above-mentioned coating layer are in the following relationship, an easy-to-adhere polyester film with excellent transparency, anti-blocking properties, and adhesion to solvent-based ink layers can be obtained.

[0047] (i) 0.5 ≤ BA(at%) ≤ 3.0

[0048] (ii) 30 ≤ b (seconds) ≤ 180

[0049] (iii) 30 ≤ cb (seconds) ≤ 300

[0050] The lower limit of BA is preferably 0.5 at%, more preferably 0.6 at%, further preferably 0.7 at%, particularly preferably 0.8 at%, and most preferably 0.9 at%. When it is 0.5 at% or higher, the amount of tough polyurethane resin is sufficient, resulting in anti-blocking properties and excellent adhesion to solvent-based ink layers, which is preferred. The upper limit of BA is preferably 3.0 at%, more preferably 2.9 at%, further preferably 2.8 at%, particularly preferably 2.7 at%, and most preferably 2.5 at%. When it is 3.0 at% or lower, the haze is low, resulting in transparency, which is preferred.

[0051] The lower limit of b is preferably 30 seconds. When it is 30 seconds or more, it is preferred to maintain the toughness of the coating layer surface on the opposite side of the polyester film substrate and obtain anti-blocking properties. The upper limit of b is preferably 180 seconds, more preferably 120 seconds, further preferably 90 seconds, and particularly preferably 60 seconds. When it is 180 seconds or less, it is preferred to maintain the toughness of the coating layer surface on the opposite side of the polyester film substrate and obtain good anti-blocking properties.

[0052] The upper limit of cb is preferably 300 seconds, more preferably 240 seconds, and even more preferably 180 seconds. When it is below 300 seconds, the polyurethane resin component in the coating layer will not become excessive, resulting in low haze and transparency, which is preferred. As for the lower limit of cb, the spectrum collection is 30 seconds or more because the pattern collection is done every 30 seconds from the start of the measurement to the 120-second etching time.

[0053] In this invention, it is preferable that the polycarbonate structural portion of the polyurethane resin in the coating layer constituting the easy-to-adhere polyester film is mostly locally present on the surface of the coating layer opposite to the polyester film substrate. This is because by having an appropriate amount of the polycarbonate structural portion present on this surface, the adhesion to various ink compositions is improved. On the other hand, it has also been found that when the polycarbonate structural portion is present on this surface, the flexibility sometimes increases, but the anti-blocking property is not necessarily sufficient. Therefore, as described above, when the characteristic values ​​read from the nitrogen element distribution curve measured by the elemental distribution of the coating layer based on the depth direction are in the following relationship, an easy-to-adhere polyester film with excellent transparency and anti-blocking properties can be obtained.

[0054] (i) 0.5 ≤ BA(at%) ≤ 3.0

[0055] (ii) 30 ≤ b (seconds) ≤ 180

[0056] (iii) 30 ≤ cb (seconds) ≤ 300

[0057] In the easily bondable polyester film of the present invention, as a means to satisfy the above formulas (i) to (iii), when synthesizing and polymerizing the polyurethane resin with a polycarbonate structure that forms the coating layer, the synthesis and polymerization are carried out by including a polycarbonate polyol component and a polyisocyanate component. The mass ratio of the polycarbonate polyol component to the polyisocyanate component is in the range of 0.5 to 2.5, the molecular weight of the polycarbonate polyol component is 500 to 1800, and when the total solid components of the polyester resin, polyurethane resin and crosslinking agent in the coating liquid are set to 100% by mass, the content of the solid components of the crosslinking agent can be listed as 10% to 50% by mass. Furthermore, by using a capped isocyanate as a crosslinking agent, and using a capped isocyanate having three or more functional isocyanate groups, efficient adjustment of BA can be achieved.

[0058] Furthermore, as described above, it is preferable that the polycarbonate structure portion of the polyurethane resin in the coating layer of the present invention exists in a certain proportion on the surface of the coating layer opposite to the polyester film substrate. In the present invention, in the surface analysis spectrum measured by X-ray photoelectron spectroscopy, the total peak area of ​​each bond type originating from the C1s spectral region is set as 100 (%), and the peak area originating from the OCOO bond (as a polycarbonate structure) is set as X (%), and expressed as a percentage.

[0059] Here, the ratio X (%) of OCOO bonds in the surface region (which is a polycarbonate structure) was evaluated by X-ray photoelectron spectroscopy (ESCA). Figure 5 , 6 Examples of graphs showing the analytical results of C1s spectra of the surface regions of the easily bondable polyester films of Example 6 and Experimental Example 1 described later are shown respectively. The gray solid line represents the measured data of the C1s spectra. The peaks of the obtained measured spectra are separated into multiple peaks, and the bond types corresponding to each peak are identified based on the position and shape of each peak. Furthermore, curve fitting is performed on the peaks from which each bond type originates, and the peak area can be calculated. The coating layer in this invention contains: a polyurethane resin having a polycarbonate structure, a crosslinking agent represented by isocyanates with 3 or more functional isocyanate groups, and a polyester resin. In the case of the above coating layer, the peaks of the bond types in Table 1 (1) to (6) can be detected. The bond types of the peaks (1) to (6) in Table 1 are not limited to the bond types shown in Table 1, and there are also cases where similar bond types are contained in trace amounts. Here, the relevant example 6 Figure 5 The C=O bond peak in (3) and the π-π* binding peak in (6) of Table 1 were not shown. Additionally, the peaks related to Experimental Example 1 were not displayed. Figure 6 The C=O bond peak of (3) and the OCOO bond peak of (5) in Table 1 are not shown. The ratio X (%) of OCOO bonds in the surface region can be said to be the percentage (%) of the area ratio of peak (5) when the peak areas of peaks (1) to (6) are taken as 100%.

[0060] [Table 1]

[0061] Key species (1) Black two-dot dashed line CC key (2) Black dashed line CO bond, CN bond (3) Black three-dot dashed line C=O bond (4) Black dotted line COO key (5) Black dashed line OCOO key (6) Black solid line π-π* bond

[0062] The suitable range for 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%, further preferably 3.0%, particularly preferably 3.5%, and most preferably 4.0%. A value of 2.0% or higher is preferred as it effectively satisfies ink adhesion requirements. The upper limit of X is preferably 10.0%, more preferably 9.0%, further preferably 8.0%, particularly preferably 7.5%, and most preferably 7%. A value below 10.0% is preferred as it prevents excessive surface softness and facilitates anti-blocking properties.

[0063] As a method for manufacturing the easily adhesive polyester film in this invention, when synthesizing and polymerizing the polyurethane resin with a polycarbonate structure that forms the coating layer, the mass ratio of the polycarbonate polyol component to the polyisocyanate component is 0.5 or higher. When the total solid components of the polyester resin, the polyurethane resin with a polycarbonate structure, and the crosslinking agent in the coating liquid are set to 100% by mass, and the polyurethane resin content is 5% to 50% by mass, it is preferable that the aforementioned X characteristic value based on the C1s spectral region can be effectively achieved in the range of 2.0 to 10.0%.

[0064] (Coating layer)

[0065] The easily adhesive polyester film of this invention preferably comprises a coating layer formed by laminating a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin on at least one side of the film to improve adhesion to the ink layer. The coating layer may be provided on both sides of the polyester film, may be provided only on one side of the polyester film, or may be provided on the other side with a different type of resin covering layer.

[0066] The components of the coating layer are described in detail below.

[0067] (Polyurethane resin)

[0068] The polyurethane resin with a polycarbonate structure in this invention has at least an urethane bond moiety derived from the polycarbonate polyol component and the polyisocyanate component, and further includes a chain extender as needed.

[0069] The lower limit of the mass ratio (mass of polycarbonate polyol to polyisocyanate) during the synthesis and polymerization of the polycarbonate-structured polyurethane resin of the present invention is preferably 0.5, more preferably 0.6, further preferably 0.7, particularly preferably 0.8, and most preferably 1.0. When it is 0.5 or higher, the proportion X of OCOO bonds on the surface of the coating layer can be efficiently adjusted to 2% or more, which is preferable. The upper limit of the mass ratio (mass of polycarbonate polyol to polyisocyanate) during the synthesis and polymerization of the polycarbonate-structured polyurethane resin of the present invention is preferably 2.5, more preferably 2.2, further preferably 2.0, particularly preferably 1.7, and most preferably 1.5. When it is 2.5 or lower, the proportion X of OCOO bonds on the surface of the coating layer can be efficiently adjusted to 10% or less, which is preferable. Furthermore, based on the nitrogen distribution curve determined by the elemental distribution in the depth direction by X-ray photoelectron spectroscopy, BA can be effectively adjusted to 0.5 at% or higher, and cb can be effectively adjusted to 300 seconds or less.

[0070] For the synthesis and polymerization of the polycarbonate-structured polyurethane resin of the present invention, the polycarbonate polyol component preferably contains an aliphatic polycarbonate polyol with excellent heat resistance and hydrolysis resistance. Examples of aliphatic polycarbonate polyols include aliphatic polycarbonate diols and aliphatic polycarbonate triols, and aliphatic polycarbonate diols are suitable for use. Examples of aliphatic polycarbonate diols used for the synthesis and polymerization of the polycarbonate-structured polyurethane resin of the present invention include: 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, neopentanediol, diethylene glycol, dipropylene glycol, etc., obtained by reacting one or more of these diols with carbonates such as dimethyl carbonate, ethylene carbonate, and carbonyl chloride.

[0071] The number-average molecular weight of the polycarbonate polyol mentioned above in this invention is preferably 500 to 1800. More preferably 600 to 1700, and most preferably 700 to 1500. When it is 500 or higher, it is preferable that the proportion X of OCOO bonds on the surface of the coating layer can be effectively adjusted to 10% or less. When it is 1800 or lower, it is preferable that the BA can be effectively adjusted to 0.5 or higher and the cb can be effectively adjusted to 300 seconds or less in the nitrogen distribution curve determined by the elemental distribution in the depth direction by X-ray photoelectron spectroscopy.

[0072] As for the polyisocyanates used in the synthesis and polymerization of the polyurethane resin having a polycarbonate structure in this invention, examples include aromatic aliphatic diisocyanates such as diphenylmethylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane and other alicyclic diisocyanates, hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates, or compounds thereof, obtained by pre-addition of one or more with trimethylolpropane and the like. Using the aforementioned aromatic aliphatic diisocyanates, alicyclic diisocyanates, or aliphatic diisocyanates is preferable because there is no yellowing problem. Furthermore, it is preferable that the coating does not become excessively hard, that it can mitigate the stress caused by the thermal shrinkage of the polyester film substrate, and that its adhesion is good.

[0073] Chain extenders include: diols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; polyols such as glycerol, trimethylolpropane, and pentaerythritol; diamines such as ethylenediamine, hexamethylenediamine, and piperazine; amino alcohols such as monoethanolamine and diethanolamine; thiodiethylene glycols such as thiodiethylene glycol; or water.

[0074] The coating layer in this invention preferably uses an aqueous coating solution and is applied using the online coating method described later. Therefore, the polyurethane resin of this invention is expected to be water-soluble or water-dispersible. It should be noted that the aforementioned "water-soluble or water-dispersible" refers to dispersion in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

[0075] To impart water dispersibility to polyurethane resins, (copolymer) sulfonic acid (salt) groups or carboxylic acid (salt) groups can be introduced into the urethane molecular backbone. To maintain moisture resistance, the introduction of weakly acidic carboxylic acid (salt) groups is suitable. Alternatively, nonionic groups such as polyoxyalkylene groups can also be introduced.

[0076] To introduce carboxylic acid (salt) groups into polyurethane resins, polyols containing carboxylic acid groups, such as dimethylolpropionic acid and dimethylolbutyric acid, are introduced as copolymer components and neutralized by a salt-forming agent. Specific examples of salt-forming agents include trialkylamines such as ammonia, 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.

[0077] To impart water dispersibility, when using a polyol compound with a carboxylic acid (salt) group as a copolymer component, the preferred molar ratio of the polyol compound with a carboxylic acid (salt) group in the polyurethane resin is 3 to 60 mol%, preferably 5 to 40 mol%, when the total polyisocyanate content of the polyurethane resin is set to 100 mol%. When the aforementioned molar ratio is less than 3 mol%, water dispersibility sometimes becomes difficult. Furthermore, when the aforementioned molar ratio exceeds 60 mol%, water resistance decreases, and therefore, resistance to damp heat sometimes decreases.

[0078] To improve rigidity, the polyurethane resin of the present invention can be end-bonded with capped isocyanate.

[0079] (Cross-linking agent)

[0080] In this invention, the crosslinking agent contained in the composition for forming the coating layer is preferably a capped isocyanate, more preferably a capped isocyanate with three or more functions, and particularly preferably a capped isocyanate with four or more functions. These properties improve anti-blocking properties. When using a capped isocyanate crosslinking agent, it is preferable that the BA (basic oxygen energy) can be effectively adjusted to 0.5 at% or more in the nitrogen distribution curve based on the elemental distribution in the depth direction determined by X-ray photoelectron spectroscopy.

[0081] The lower limit of the boiling point of the aforementioned capping agent for the isocyanate is preferably 150°C, more preferably 160°C, further preferably 180°C, particularly preferably 200°C, and most preferably 210°C. A higher boiling point of the capping agent can suppress the volatilization of the capping agent during the drying process after coating, and in the case of online coating methods, even through thermal addition in the film-forming process, thus suppressing the occurrence of minor coating surface unevenness and improving the transparency of the film. There is no particular upper limit to the boiling point of the capping agent; from a productivity perspective, approximately 300°C is considered the upper limit. Boiling point is related to molecular weight; therefore, to increase the boiling point of the capping agent, it is preferable to use a capping agent with a large molecular weight, preferably 50 or higher, more preferably 60 or higher, and further preferably 80 or higher.

[0082] The upper limit of the dissociation temperature of the capping agent is preferably 200°C, more preferably 180°C, further preferably 160°C, particularly preferably 150°C, and most preferably 120°C. In the case of the drying process after coating the coating liquid or in the case of online coating method, the capping agent dissociates from the functional groups through thermal addition in the film forming process to generate regenerated isocyanate groups. Therefore, the crosslinking reaction with polyurethane resins, etc., takes place, and the adhesion is improved. When the dissociation temperature of the capping isocyanate is below the above-mentioned temperature, the dissociation of the capping agent is sufficient, and therefore the adhesion, especially the resistance to damp heat, becomes good.

[0083] As end-capping agents for the present invention, whose dissociation temperature is below 120°C and whose boiling point is above 150°C, examples 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 malonate (dimethyl malonate, diethyl malonate, di-n-butyl malonate, and di-2-ethylhexyl malonate), methyl ethyl ketone, etc.; and triazole compounds such as 1,2,4-triazole. Among these, pyrazole compounds are preferred considering their resistance to damp heat and yellowing.

[0084] The polyisocyanate used as a precursor to the capped isocyanate in this invention can be obtained by introducing diisocyanate. Examples include polyurethane-modified diisocyanates, urea-modified diisocyanates, biuret-modified diisocyanates, urea-dione-modified diisocyanates, urea-dione-imine-modified diisocyanates, isocyanurate-modified diisocyanates, and carbodiimine-modified diisocyanates.

[0085] Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, benzene diisocyanate, tetramethylphenyldimethyl diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, and 3,3'- Aromatic diisocyanates such as dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate; aromatic aliphatic diisocyanates such as phenyldimethyl diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanate methyl)cyclohexane; and aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate. Considering transparency, adhesion, and resistance to damp heat, aliphatic and alicyclic isocyanates, and their modified forms, are preferred, especially for optical applications requiring minimal yellowing and high transparency.

[0086] For the capped isocyanate in this invention, in order to impart water solubility or water dispersibility, a hydrophilic group can be introduced into the polyisocyanate used as a precursor. Examples of hydrophilic groups include (1) quaternary ammonium salts of dialkylamino alcohols and quaternary ammonium salts of dialkylaminoalkylamines, (2) sulfonates, carboxylates, phosphates, etc., and (3) polyethylene glycol and polypropylene glycol obtained by single capping with alkoxy groups. When a hydrophilic site is introduced, it becomes (1) cationic, (2) anionic, or (3) nonionic. Most other water-soluble resins are anionic, so anionic or nonionic resins that are easily compatible are preferred. In addition, anionic resins have excellent compatibility with other resins, and nonionic resins do not have ionic hydrophilic groups, so they are also preferred to improve resistance to damp heat.

[0087] As anionic hydrophilic groups, those having hydroxyl groups for introducing into the polyisocyanate and carboxylic acid groups for imparting hydrophilicity are preferred. Examples include glycolic acid, lactic acid, tartaric acid, citric acid, hydroxybutyric acid, hydroxyvalerate, hydroxypentanoic acid, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, and polycaprolactones having carboxylic acid groups. Organic amine compounds are preferred for neutralizing the carboxylic acid groups. Examples include ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, ethylenediamine, and other linear or branched primary, secondary, or tertiary amines with 1 to 20 carbon atoms; cyclic amines such as morpholine, N-alkylmorpholine, and pyridine; monoisopropanolamine, methylethanolamine, methylisopropanolamine, dimethylethanolamine, diisopropanolamine, diethanolamine, triethanolamine, diethylethanolamine, and triethanolamine containing hydroxyl groups.

[0088] As a nonionic hydrophilic group, the repeating units of polyethylene glycol, polypropylene glycol, ethylene oxide, and / or propylene oxide obtained by single-termining with alkoxy groups are preferably 3 to 50, more preferably 5 to 30. When the repeating units are small, the compatibility with the resin deteriorates, and the haze increases; when the repeating units are large, the adhesion under high temperature and humidity conditions may decrease. For the terminated isocyanate of the present invention, nonionic, anionic, cationic, or amphoteric surfactants can be added to improve water dispersibility. Examples include nonionic surfactants such as polyethylene glycol and polyol fatty acid esters, fatty acid salts, alkyl sulfates, alkylbenzene sulfonates, sulfosuccinates, and alkyl phosphates, anionic surfactants such as alkylamine salts and alkyl betaines, cationic surfactants such as carboxylic acid amine salts, sulfonic acid amine salts, and sulfate ester salts.

[0089] In addition to water, water-soluble organic solvents may also be included. For example, organic solvents used in the reaction may be added, or they may be removed and replaced with other organic solvents.

[0090] (Polyester resin)

[0091] The polyester resin used to form the coating layer in this invention can be a linear polyester resin, more preferably a polyester resin in which dicarboxylic acid and branched diols are constituent components. The dicarboxylic acid referred to here, besides having terephthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid as its main component, can include 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. In addition, branched diols are diols with branched alkyl groups, such as 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.

[0092] The polyester resin preferably contains a branch of diol component, preferably at a proportion of 10 mol% or more, and more preferably at a proportion of 20 mol% or more, as described above more preferably, in its total diol component. Ethylene glycol is most preferably the diol component other than the compounds mentioned above. If used in small quantities, diethylene glycol, propylene glycol, butanediol, hexanediol, or 1,4-cyclohexanediol may also be used.

[0093] For the dicarboxylic acid that forms a component of the aforementioned polyester resin, terephthalic acid or isophthalic acid is most preferred. If in small quantities, other dicarboxylic acids, particularly aromatic dicarboxylic acids such as diphenylcarboxylic acid and 2,6-naphthalenedicarboxylic acid, may be added for copolymerization. In addition to the aforementioned dicarboxylic acids, to impart water dispersibility to the copolymer polyester resin, 5-sulfonyl isophthalic acid is preferably copolymerized in the range of 1 to 10 mol%, for example, sulfonyl terephthalic acid, 5-sulfonyl isophthalic acid, 4-sulfonylnaphthalenedicarboxy-2,7-dicarboxylic acid, 5-(4-sulfophenoxy) isophthalic acid, and their salts.

[0094] When the total solid components of the polyester resin, polyurethane resin with a polycarbonate structure, and crosslinking agent in the coating liquid are set to 100% by mass, the lower limit of the crosslinking agent content is preferably 5% by mass, more preferably 7% by mass, further preferably 10% by mass, and most preferably 12% by mass. When it is 5% by mass or more, it is preferable to easily adjust BA to 0.5 at% or more based on the nitrogen distribution curve determined by X-ray photoelectron spectroscopy in the depth direction. The upper limit of the crosslinking agent content is preferably 50% by mass, more preferably 40% by mass, further preferably 35% by mass, and most preferably 30% by mass. When it is 50% by mass or less, it is preferable to easily adjust cb to 300 seconds or less based on the nitrogen distribution curve determined by X-ray photoelectron spectroscopy in the depth direction.

[0095] When the total solid components of the polyester resin, polyurethane resin with a polycarbonate structure, and crosslinking agent in the coating solution are set to 100% by mass, the lower limit of the content of polyurethane resin with a polycarbonate structure is preferably 5% by mass. When it is 5% by mass or more, it is preferable to easily adjust the proportion X of OCOO bonds on the surface of the coating layer to 2.0% or more. The upper limit of the content of polyurethane resin with a polycarbonate structure is preferably 50% by mass, more preferably 40% by mass, further preferably 30% by mass, and most preferably 20% by mass. When the content of polyurethane resin is 50% by mass or less, it is preferable to easily adjust the proportion X of OCOO bonds on the surface of the coating layer to 10.0% or less.

[0096] When the total solid content of polyester resin, polyurethane resin, and crosslinking agent in the coating solution is set to 100% by mass, the lower limit of the polyester resin content is preferably 10% by mass, more preferably 20% by mass, further preferably 30% by mass, particularly preferably 35% by mass, and most preferably 40% by mass. When the polyester resin content is 10% by mass or more, the adhesion between the coating layer and the polyester film substrate becomes good and is preferred. The upper limit of the polyester resin content is preferably 70% by mass, more preferably 67% by mass, further preferably 65% ​​by mass, particularly preferably 62% by mass, and most preferably 60% by mass. When the polyester resin content is 70% by mass or less, the resistance to damp heat after UV ink processing becomes good and is preferred.

[0097] (additive)

[0098] In the coating layer of this invention, known additives such as surfactants, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic particles, antistatic agents, nucleating agents, etc., may be added without hindering the effects of this invention.

[0099] In this invention, adding particles to the coating layer is a preferred method to further improve the anti-blocking properties of the coating layer. Examples of particles contained in the coating layer of this invention include titanium dioxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, or mixtures thereof. Furthermore, examples include inorganic particles used in combination with other common inorganic particles such as calcium phosphate, mica, lithium montmorillonite, zirconium oxide, tungsten oxide, lithium fluoride, calcium fluoride, etc., as well as styrene-based, acrylic-based, melamine-based, benzoguanamine-based, organosilicon-based, and other organic polymer-based particles.

[0100] The average particle size (based on the number of particles observed by a scanning electron microscope (SEM), hereinafter the same) in the coating layer 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 becomes easier to form irregularities on the film surface, thus improving the film's operability, such as its sliding and winding properties, and resulting in good 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, particle shedding is less likely to occur, which is preferable. The particle concentration in the coating layer is preferably 1 to 20% by mass of the solid composition.

[0101] The average particle size can be determined by, for example, observing the particles in the cross-section of the easily bondable polyester film using a scanning electron microscope, observing 30 particles, and taking their average value as the average particle size.

[0102] The shape of the particles is not particularly limited as long as the purpose of this invention is met; spherical particles or irregularly shaped non-spherical particles can be used. The particle size of irregularly shaped particles can be calculated in the form of the equivalent diameter of a circle. The equivalent diameter of a circle is obtained by dividing the observed area of ​​the particle by π and calculating the square root, making it twice.

[0103] (Manufacturing of easy-to-adhere polyester film)

[0104] The method for manufacturing the easily adhesive polyester film of the present invention is illustrated by using polyethylene terephthalate (hereinafter sometimes abbreviated as PET) film substrate as an example, but is of course not limited thereto.

[0105] After the PET resin is thoroughly vacuum dried, it is fed into an extruder. Molten PET resin at approximately 280°C is extruded from a T-die in sheet form onto a rotating cooling roller. The resin is then cooled and cured using an electrostatic application method to obtain an unstretched PET sheet. The aforementioned unstretched PET sheet can be a single layer or a multilayer structure based on a co-extrusion method.

[0106] Crystal orientation is achieved by applying uniaxial or biaxial stretching to the obtained unstretched PET sheet. For example, in the case of biaxial stretching, the film is stretched 2.5 to 5.0 times its original length using rollers heated to 80–120°C to obtain a uniaxially stretched PET film. The film is then held at the ends by a clamp and introduced into a hot air zone heated to 80–180°C, where it is stretched 2.5 to 5.0 times its original width. Alternatively, in the case of uniaxial stretching, the film is stretched 2.5 to 5.0 times its original width in a tenter frame. After stretching, the film is then introduced into a heat treatment zone for heat treatment to complete the crystal orientation.

[0107] 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, curing becomes sufficient, and the anti-blocking properties in the presence of liquid water are good, which is preferable, eliminating the need for extended drying time. 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 below 230°C, there is no concern about a decrease in the physical properties of the film, which is preferable.

[0108] The coating layer can be applied after film manufacturing or during the manufacturing process. In particular, from a productivity perspective, it is preferable to form the coating layer at any stage of the film manufacturing process, i.e., on at least one side of the PET film after it has been unstretched or uniaxially stretched, by applying a coating liquid.

[0109] The method for applying the coating liquid to the PET film can be any known method. Examples include reverse roller coating, gravure coating, coincidence coating, die coating, roller brush coating, spray coating, air knife coating, wire rod coating, tubular blade coating, dip coating, curtain coating, etc. These methods can be used individually or in combination.

[0110] In this invention, the thickness of the coating layer can be appropriately set within the range of 0.001 to 2.00 μm. To balance processability and adhesion, a range of 0.01 to 1.00 μm is preferred, 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 preferred due to good adhesion. A coating layer thickness of 2.00 μm or less is preferred because it reduces the likelihood of adhesion.

[0111] The upper limit of haze of the easily bondable polyester film in this invention is preferably 1.5%, more preferably 1.3%, further preferably 1.2%, and particularly preferably 1.0%. When the haze is 1.5% or less, it is preferred from the perspective of transparency and can also be suitably used for optical films that require transparency.

[0112] (UV-curable ink)

[0113] The UV-curable ink of this invention refers to a general term for inks cured by ultraviolet light. It comprises pigments (dyes), oligomers and monomers, photopolymerization initiators and accelerators, and auxiliary agents. The oligomers and monomers act as flow components in the main component, spreading onto the printed substrate and then cured by free radicals generated by the photopolymerization initiator under ultraviolet light. The proportions of oligomers and monomers vary depending on the printing method described later. Essentially, except for viscosity adjustment purposes, it contains no solvent, or if it does, it preferably contains at most about 10 parts by weight.

[0114] As the UV-curable ink of the present invention, lightfast UV-curable ink and UV-curable screen printing ink are particularly preferred.

[0115] (Lightfast UV curable ink)

[0116] The UV-curable lightfast ink of this invention preferably contains a UV absorber. The UV absorber prevents UV-induced coating degradation by absorbing the irradiated UV light. The content of the UV absorber relative to the total amount of ink is preferably 0.5 to 10 parts by weight, more preferably 1 to 3 parts by weight. When the content of the UV absorber is less than 0.5%, the lamination strength tends to deteriorate after UV irradiation due to coating degradation; when it is 10% or more, it may inhibit the initial adhesion to the printed material by suppressing the softness of the resin contained in the ink. The UV absorber can be used alone or in combination of two or more types. The ultraviolet absorber may be any one of the following: benzotriazole-based ultraviolet absorbers containing a benzotriazole skeleton with olefinic unsaturated bonds; benzophenone-based ultraviolet absorbers containing a benzophenone skeleton; salicylic acid-based ultraviolet absorbers with salicylic acid in the skeleton; cyanoacrylate-based ultraviolet absorbers containing a cyanoacrylate skeleton; hindered phenol-based ultraviolet absorbers containing a hindered phenol skeleton; and triazine-based ultraviolet absorbers with triazine in the skeleton, or a combination of two or more.

[0117] For example, laminated products may be stored under light for extended periods. The free radicals generated under such conditions reduce the cohesiveness or adhesion of the printing ink film, leading to a decrease in lamination strength. Therefore, when opening laminates stored under light for extended periods, there is a concern about interlayer peeling, thus requiring lightfastness.

[0118] (UV-curable screen printing ink)

[0119] The UV-curable screen printing ink of this invention preferably contains an acrylic resin acrylate. The acrylic resin acrylate may have an acid value. Having an acid value promotes dispersion with the colorant. As a result, clogging during screen printing can be prevented, providing a printable layer with high appearance. From the viewpoint of improving pigment dispersion, the acid value of the acrylic resin acrylate is preferably 10 mg KOH / g or higher.

[0120] As a method for imparting an acid value to acrylate resins, a copolymerization method comprising a monomer having an acid value can be exemplified. Examples of monomers 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, among which (meth)acrylic acid is preferred.

[0121] (Screen printing)

[0122] Screen printing is a type of stencil printing where ink is placed on a plate between holes and extruded to the opposite side using a squeegee called a squeegee, thus applying the ink to the substrate. Compared to other printing methods, it offers a high degree of freedom in terms of the amount of ink that can be printed and the type of substrate. Furthermore, screen printing is characterized by its ability to significantly adjust the ink thickness (printed film thickness) compared to other printing methods.

[0123] (Solvent-based ink)

[0124] In this invention, solvent-based ink refers to a general term for inks that are cured by evaporation and drying. It comprises pigments (dyes), resin components, diluents, and additives. The ink dries extremely quickly, leaving the resin and pigment components fixed on the printed surface after the solvent rapidly evaporates. Therefore, it is suitable for high-speed / mass printing.

[0125] Oxidative Polymer Ink

[0126] (Oxidation-polymerized ink)

[0127] The oxidative polymerization ink of this invention is an ink with drying oil as its main component, which has the property of polymerization / curing by oxygen in the air. It also includes pigments (dyes), polymerization accelerators, and auxiliary agents. The drying oil acts as a flow component, and its viscosity is adjusted according to the printing method. Recently, composite types containing both UV-curing components and drying oil have also existed. The solvents described above mainly refer to organic solvents, such as hexane and heptane as hydrocarbons, methyl acetate and ethyl acetate as esters, acetone and MEK as ketones, etc., and mixtures of these alone or with alcohols can be listed. Monomers, oligomers, and oils with polymerization / curing properties are not included in the organic solvent. Printing methods using these methods include flexographic printing, screen printing, and offset printing. The latter allows for a higher ink viscosity setting.

[0128] (Heat transfer ink)

[0129] The heat transfer ink of this invention is a heat-melting pigment ink, used in a heat transfer printing method where ink coated on an ink ribbon is melted by heat and transferred to paper for printing. It is an ink composed of colorants such as pigments / dyes, binders such as waxes / thermoplastic resins, softeners / dispersants, and various additives. Resin-type and wax-type inks can be used for heat transfer printing. Resin-type inks are particularly suitable due to their excellent weather resistance. Applications include monochrome document output for word processors, tape typewriters, and barcode label printers. Additionally, by using color ribbons, it is also used in color printers and image printers.

[0130] (LBP toner)

[0131] The toner in this invention is a powder used for coloring in laser printers and copiers. It is a substance mixed with charged microparticles (polymer resin), wax, pigments, etc. In the case of color printing, four colors are used: blue-green, red-purple, yellow, and black. LBP refers to a page printer that uses a laser to charge the rollers and uses electrostatic adhesion of the toner.

[0132] Example

[0133] 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.

[0134] [Manufacturing of polyester resin granules P-1]

[0135] High-purity terephthalic acid and twice the molar amount of ethylene glycol were added to a 2-liter stainless steel autoclave equipped with a stirrer. Triethylamine (0.3 mol%) was added relative to the acid content. Esterification was carried out at 250°C under pressure of 0.25 MPa, with water distilled off the system, yielding a mixture of bis(2-hydroxyethyl) terephthalate and oligomers with an esterification rate of approximately 95% (hereinafter referred to as the BHET mixture). Next, while stirring the BHET mixture, an ethylene glycol solution of antimony trioxide as a polymerization catalyst was added at 0.04 mol% (based on antimony atoms) relative to the acid content in the polyester. The mixture was then stirred for 10 minutes at atmospheric pressure and 250°C under a nitrogen atmosphere. The temperature was then increased to 280°C over 60 minutes, and the pressure of the reaction system was gradually reduced to 13.3 Pa (0.1 Torr), subsequently carrying out a polycondensation reaction at 280°C and 13.3 Pa. After releasing the pressure, the resin under slight pressure is sprayed into cold water in the form of a filament for rapid cooling. After being kept in cold water for 20 seconds, it is cut to obtain granules in the shape of a barrel with a length of about 3 mm and a diameter of about 2 mm.

[0136] The polyester granules obtained from melt polymerization were subjected to reduced pressure drying (below 13.3 Pa, 80°C, 12 hours), followed by crystallization treatment (below 13.3 Pa, 130°C, 3 hours, then below 13.3 Pa, 160°C, 3 hours). The cooled polyester granules were then subjected to solid-phase polymerization in a solid-phase polymerization reactor while maintaining the system temperature below 13.3 Pa and 215°C, resulting in polyester granules with an intrinsic viscosity of 0.62 dl / g.

[0137] [Manufacturing of Polyester Granules P-2]

[0138] (Preparation of aluminum compounds)

[0139] For a 20 g / L aqueous solution of basic aluminum acetate (aluminum hydroxydiacetate; manufactured by Aldrich) prepared by heating at 80 °C for 2 hours with stirring and confirming a chemical shift of the peak position of the 27Al-NMR spectrum towards the low magnetic field side, an equal volume (capacity ratio) of ethylene glycol was added to a flask. After stirring at room temperature for 6 hours, water was distilled off the system while stirring under reduced pressure (133 Pa) at 90–110 °C for several hours to prepare a 20 g / L ethylene glycol solution of aluminum compound.

[0140] (Preparation of phosphorus compounds)

[0141] Irganox1222 (manufactured by Ciba Japan KK), a phosphorus compound, was added to a flask along with ethylene glycol. The mixture was heated at 160°C for 25 hours under nitrogen purging with stirring to prepare a 50 g / L ethylene glycol solution of the phosphorus compound. 31P-NMR spectroscopy confirmed that approximately 60 mol% was converted to hydroxyl groups.

[0142] (Preparation of a mixture of ethylene glycol solutions of aluminum compounds and ethylene glycol solutions of phosphorus compounds)

[0143] The ethylene glycol solutions obtained in the preparation of the above aluminum compound and the preparation of the above phosphorus compound were added to a flask, and aluminum atoms and phosphorus atoms were mixed at a molar ratio of 1:2 at room temperature. The mixture was stirred for 1 day to prepare a catalyst solution. The chemical shift was confirmed in the 27Al-NMR and 31P-NMR spectra of this mixed solution under all conditions.

[0144] As a polycondensation catalyst, a mixture of ethylene glycol solutions of the aforementioned aluminum compound and ethylene glycol solutions of the phosphorus compound was added at a concentration of 0.014 mol% and 0.028 mol% (calculated as aluminum atoms and phosphorus atoms, respectively) relative to the acid content in the polyester. Otherwise, the same operation as in the production of polyester granules P-1 was performed. Polyester granules P-2 with an intrinsic viscosity of 0.65 dl / g were obtained.

[0145] (Polymerization of polyurethane resin A-1 with a polycarbonate structure)

[0146] In a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 32 parts by weight of 1,3-cyclohexyl diisocyanate, 7 parts by weight of dimethylolpropionic acid, 58 parts by weight of polyhexamethylene carbonate diol with a number average molecular weight of 800, 3 parts by weight of neopentyl glycol, and 84.00 parts by weight of acetone as a solvent were added. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached the specified amine equivalent. Next, the reaction solution was cooled to 40°C, and 5.17 parts by weight of triethylamine were added to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed disperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred at a high speed for 2000 min... -1 The mixture was stirred and mixed while adding the polyurethane prepolymer solution for water dispersion. Then, by removing a portion of the acetone and water under reduced pressure, a water-dispersible polyurethane resin solution (A-1) with a solid content of 34% was prepared.

[0147] (Polymerization of polyurethane resin A-2 with a polycarbonate structure)

[0148] In a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 38 parts by weight of 4,4-dicyclohexylmethane diisocyanate, 9 parts by weight of dimethylolpropionic acid, 53 parts by weight of polyhexamethylene carbonate diol with a number average molecular weight of 1000, and 84.00 parts by weight of acetone as a solvent were added. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached the specified amine equivalent. Next, the reaction solution was cooled to 40°C, and 5.17 parts by weight of triethylamine were added to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed disperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred at a high speed for 2000 min... -1 The mixture was stirred and mixed while adding the polyurethane prepolymer solution for water dispersion. Then, by removing a portion of the acetone and water under reduced pressure, a water-dispersible polyurethane resin solution (A-2) with a solid content of 35% was prepared.

[0149] (Polymerization of polyurethane resin A-3 with a polycarbonate structure)

[0150] In a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 30 parts by weight of 4,4-dicyclohexylmethane diisocyanate, 16 parts by weight of polyethylene glycol monomethyl ether with a number average molecular weight of 700, 50 parts by weight of polyhexamethylene carbonate glycol with 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 were added. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached the specified amine equivalent. Next, the reaction solution was cooled to 40°C to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed disperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred at a high speed for 2000 min... -1 The mixture was stirred and mixed while adding the polyurethane prepolymer solution for water dispersion. Then, by removing a portion of the acetone and water under reduced pressure, a water-dispersible polyurethane resin solution (A-3) with a solids content of 35% was prepared.

[0151] (Polymerization of polyurethane resin A-4 with a polycarbonate structure)

[0152] In a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 24 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 4 parts by mass of dimethylolbutyric acid, 71 parts by mass of polyhexamethylene carbonate glycol 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. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached the specified amine equivalent. Next, the reaction solution was cooled to 40°C, and 8.77 parts by mass of triethylamine were added to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed disperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred at a high speed for 2000 min... -1 The mixture was stirred and mixed while adding the polyurethane prepolymer solution for water dispersion. Then, by removing a portion of the acetone and water under reduced pressure, a water-dispersible polyurethane resin solution (A-4) with a solid content of 34% by mass was prepared.

[0153] (Polymerization of polyurethane resin A-5 without polycarbonate polyol components)

[0154] A multi-stage isocyanate addition polymerization method using polyether polyol, organic polyisocyanate, and diethylene glycol as a chain extender was employed, reacting at 70–120°C for 2 hours. The resulting urethane prepolymer was mixed with an aqueous solution of bisulfite and reacted with thorough stirring for approximately 1 hour to achieve end-capping. The reaction temperature was set below 60°C. Then, the solution was diluted with water to prepare a 20% by weight thermally reactive water-dispersible polyurethane resin solution (A-5).

[0155] (Polymerization of polyurethane resin A-6 with a polycarbonate structure)

[0156] In a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 54 parts by weight of 4,4-dicyclohexylmethane diisocyanate, 16 parts by weight of polyethylene glycol monomethyl ether with a number average molecular weight of 700, 18 parts by weight of polyhexamethylene carbonate glycol with 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 were added. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached the specified amine equivalent. Next, the reaction solution was cooled to 40°C, and 8.77 parts by weight of triethylamine were added to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed disperser capable of high-speed stirring, and the temperature was adjusted to 25°C. The mixture was stirred at a high speed for 2000 min... -1 The mixture was stirred and mixed while adding the polyurethane prepolymer solution for water dispersion. Then, by removing a portion of the acetone and water under reduced pressure, a water-dispersible polyurethane resin solution (A-6) with a solid content of 34% by mass was prepared.

[0157] Table 2 shows the following two items.

[0158] I. The mass ratio of polycarbonate polyol to polyisocyanate components during the synthesis and polymerization of the polyurethane resin that forms the coating layer (polycarbonate polyol component / polyisocyanate component).

[0159] II. Molecular weight of polycarbonate polyol components

[0160] [Table 2]

[0161]

[0162] (Polymerization of end-capped isocyanate crosslinking agent B-1)

[0163] In a flask equipped with a stirrer, thermometer, and reflux condenser, 66.04 parts by mass of a polyisocyanate compound with an isocyanurate structure (manufactured by Asahi Kasei Chemicals Corporation, DURANATE TPA) using hexamethylene diisocyanate as a raw material and 17.50 parts by mass of N-methylpyrrolidone were added dropwise, followed by 25.19 parts by mass of 3,5-dimethylpyrazole (dissociation temperature: 120℃, boiling point: 218℃). The mixture was kept at 70℃ for 1 hour under a nitrogen atmosphere. Then, 5.27 parts by mass of dimethylolpropionic acid were added dropwise. After confirming the disappearance of the isocyanate group absorption by measuring the infrared spectrum of the reaction solution, 5.59 parts by mass of N,N-dimethylethanolamine and 132.5 parts by mass of water were added to obtain a block polyisocyanate aqueous dispersion (B-1) with a solid content of 40% by mass. The number of functional groups of this end-capped isocyanate crosslinking agent is 4.

[0164] (Polymerization of end-capped isocyanate crosslinking agent B-2)

[0165] In a flask equipped with a stirrer, thermometer, and reflux condenser, 100 parts by weight of a polyisocyanate compound (manufactured by Asahi Kasei Chemicals Corporation, DURANATE TPA) with an isocyanurate structure, using hexamethylene diisocyanate as a raw material, 55 parts by weight of propylene glycol monomethyl ether acetate, and 30 parts by weight of polyethylene glycol monomethyl ether (average molecular weight 750) were added. The mixture was kept at 70°C for 4 hours under a nitrogen atmosphere. Then, the temperature of the reaction solution was lowered to 50°C, and 47 parts by weight of methyl ethyl ketone oxime were added dropwise. The infrared spectrum of the reaction solution was measured, confirming the disappearance of the isocyanate group absorption, yielding an oxime-terminated isocyanate crosslinking agent (B-2) with a solid content of 40% by weight. This oxime-terminated isocyanate crosslinking agent has 3 functional groups.

[0166] (Polymerization of carbodiimide B-3)

[0167] In a flask equipped with a stirrer, thermometer, and reflux condenser, 168 parts by weight of hexamethylene diisocyanate and 220 parts by weight of polyethylene glycol monomethyl ether (M400, average molecular weight 400) were added. The mixture was stirred at 120°C for 1 hour. Then, 26 parts by weight of 4,4'-dicyclohexylmethane diisocyanate and 3.8 parts by weight of 3-methyl-1-phenyl-2-phosphacyclopentene-1-oxide (2% by weight relative to the total isocyanate) were added as a carbodiimide catalyst. The mixture was stirred further at 185°C for 5 hours under a nitrogen atmosphere. The infrared spectrum of the reaction solution was measured, confirming the wavelength range of 220–2300 cm⁻¹. -1 The absorption disappeared. After cooling to 60°C, 567 parts by mass of ion-exchanged water were added to obtain a carbodiimide aqueous resin solution (B-3) with a solid content of 40% by mass.

[0168] (Polymerization of polyester resin C-1)

[0169] In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, 194.2 parts by weight of dimethyl terephthalate, 184.5 parts by weight of dimethyl isophthalate, 14.8 parts by weight of sodium dimethyl-5-sulfonyl isophthalate, 185 parts by weight of neopentyl glycol, 188 parts by weight of ethylene glycol, and 0.2 parts by weight of tetrabutyl titanate were added. The transesterification reaction was carried out at a temperature ranging from 160°C to 220°C for 4 hours. Then, the temperature was raised to 255°C, and the reaction system was slowly reduced in pressure, reacting under reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain copolyester resin (C-1). The obtained copolyester resin (C-1) was pale yellow and transparent. The specific viscosity of the copolyester resin (C-3) was measured to be 0.40 dl / g. The glass transition temperature based on DSC was 65°C.

[0170] (Preparation of polyester aqueous dispersion Cw-1)

[0171] In a reactor equipped with a stirrer, thermometer, and reflux device, 25 parts by weight of polyester resin (C-1) and 10 parts by weight of ethylene glycol n-butyl ether were added. The resin was dissolved by heating and stirring at 110°C. After the resin was completely dissolved, 65 parts by weight of water were slowly added to the polyester solution while stirring. After the water was added, the liquid was stirred and cooled to room temperature to prepare a milky white polyester aqueous dispersion (Cw-1) with a solid content of 25% by weight.

[0172] (Example 1)

[0173] (1) Preparation of coating solution

[0174] A coating solution with a solid content mass ratio of 25 / 26 / 49 was prepared by mixing the following coating agents in a mixed solvent of water and isopropanol: polyurethane resin solution (A-1) / crosslinking agent (B-1) / polyester aqueous dispersion (Cw-1).

[0175]

[0176]

[0177] (2) Manufacturing of easy-to-adhere polyester film

[0178] As a polymer for film production, polyester granules P-1 were dried at 135°C for 6 hours under reduced pressure of 133 Pa. Then, they were fed to an extruder and melt-extruded into sheets at approximately 280°C. The sheets were then rapidly cooled and solidified on a rotating cooling metal roller maintained at a surface temperature of 20°C to obtain unstretched PET sheets.

[0179] The unstretched PET sheet is heated to 100°C using heated rollers and an infrared heater, and then stretched 3.5 times along its length using rollers with a circumferential speed difference to obtain a uniaxially stretched PET film.

[0180] Next, the aforementioned coating solution, which had been left to stand at room temperature for more than 5 hours, was applied to one side of the PET film using a roller coating method, and then dried at 80°C for 20 seconds. It should be noted that the final (after biaxial stretching) coating weight after drying was adjusted to 0.15 g / m². 2 (The thickness of the dried coating layer is 150 nm). Next, the film is stretched to 4.0 times its original length in the width direction at 120 °C using a tenter frame. With the width direction length of the film fixed, it is heated at 230 °C for 5 seconds, and then relaxed in the width direction by 3% for 10 seconds at 100 °C to obtain a 100 μm easy-to-adhere polyester film.

[0181] (3) Printing

[0182] (Printed material with UV-curable ink layer (1): low radiation dose)

[0183] A UV-curable ink with the following composition was applied to a coated layer of easily bondable polyester film using a printer [manufactured by Meiji Seisakusho, trade name "RI Taster"]. Then, 30 seconds after printing began, the film coated with the ink was irradiated with a high-pressure mercury lamp, accumulating a light intensity of 40 mJ / cm². 2 The ultraviolet light causes the UV-curable offset printing ink to cure, resulting in a printed material with a light-resistant UV-curable ink layer (1).

[0184] (Lightfast UV curable ink)

[0185] T&K TOKA Company manufactures "BEST CURE (registered trademark) UV161 Blue S" 100 parts per batch.

[0186] 4 parts by weight of benzophenone-based ultraviolet absorber (Chemisaw 11, manufactured by Chemipro Kasei Ltd.)

[0187] (Printed material with UV-curable ink layer (2): screen printing)

[0188] On a coating layer of easily adhesive polyester film, UV-curable screen printing ink [manufactured by TOYOINK, trade name "TU240 FDSS 911INk"] was used for printing on a Tetoron screen (#250 mesh). Then, the ink-coated film was irradiated with a high-pressure mercury lamp at 500 mJ / cm². 2 The ultraviolet light causes the UV-curable screen printing ink to cure, resulting in a printed material with a UV-curable screen printing ink layer (2).

[0189] (Printed materials with UV-curable ink layers (3): High-speed printing)

[0190] Printing is performed on a coated layer of easily bondable polyester film using a lightfast UV-curable ink with the following composition, employing a central impression printer. The printing process uses an aperture volume of 11 cm³. 3 After measuring the ink with an anilox roller, it is transferred to the entire plate and then to the film. The ink transferred to the film is cured using a 160W / cm metal halide UV lamp to obtain a print with a lightfast UV-curable ink layer (3). The time from ink transfer to the film to UV irradiation is 0.94 seconds.

[0191] (Lightfast UV curable ink)

[0192] T&K TOKA Company manufactures "BEST CURE (registered trademark) UV161 Blue S" 100 parts per batch.

[0193] 4 parts by weight of benzophenone-based ultraviolet absorber (Chemisaw 11, manufactured by Chemipro Kasei Ltd.)

[0194] (Printed materials with solvent-based ink layers)

[0195] On a coating layer of easily adhesive polyester film, solvent-based ink [Jujo ink co.,ltd., 900 series Tetron ink] is used for printing using a Tetron Screen (#250 mesh). Then, the film coated with the ink layer is left to dry for 24 hours to obtain a printed product with a solvent-based ink layer.

[0196] (Printed materials with oxidative polymer ink layers)

[0197] An oxidative polymer ink (manufactured by Jujo Chemical Co., Ltd., black) was diluted with a diluent (manufactured by Jujo Chemical Co., Ltd., Teton) at a volume ratio of ink:diluent = 4:1. The ink was then printed on the surface of a film (or the surface of the coating layer if one is present) through a Teton Screen (#250 mesh). After drying for 24 hours, a printed material with an oxidative polymer ink layer was obtained.

[0198] (Printed materials with heat transfer ink layers)

[0199] Using a heat transfer tape (made by RICOH COMPANY, LTD., B-110C resin type, black), mounted on a BonElectric Co., Ltd. BLP-323, any barcode pattern can be printed on a coating layer of an easily adhesive polyester film to obtain a printed material with a heat transfer ink layer.

[0200] (Printed material with LBP toner layer)

[0201] Using FUJI XEROX's ApeosPort-V C3376, any pattern can be printed on a coating layer of an easy-to-adhere polyester film to obtain a printed material with an LBP toner layer.

[0202] The evaluation results are shown in Table 5.

[0203] (Example 2)

[0204] By changing the polyurethane resin to (A-2), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 1.

[0205] (Example 3)

[0206] By changing the polyurethane resin to (A-3), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 1.

[0207] (Example 4)

[0208] By changing the crosslinking agent to (B-2), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 1.

[0209] (Example 5)

[0210] The following coating agent was mixed in a mixed solvent of water and isopropanol to change the solid component mass ratio of polyurethane resin solution (A-1) / crosslinking agent (B-1) / polyester aqueous dispersion (Cw-1) to 22 / 10 / 68. Otherwise, an easy-to-adhere polyester film and print were obtained in the same manner as in Example 1.

[0211]

[0212]

[0213] (Example 6)

[0214] By changing the polyurethane resin to (A-2), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 5.

[0215] As shown in Table 5, in Examples 1 to 6, “BA”, “b” and “cb” respectively satisfy the range of the following formula, which can satisfy the requirements of haze and anti-adhesion.

[0216] (i) 0.5 ≤ BA(at%) ≤ 3.0

[0217] (ii) 30 ≤ b (seconds) ≤ 180

[0218] (iii) 30 ≤ cb (seconds) ≤ 300

[0219] Furthermore, "X" satisfies the following formula, ensuring excellent adhesion to each ink layer. This indicates that it also exhibits excellent adhesion to UV-curable inks during low-radiation-dose processing and high-speed printing.

[0220] (iv) 2.0 ≤ X (%) ≤ 10.0

[0221] (Example 7)

[0222] As the polymer used as the film raw material, the polyester granules were changed to (P-2), otherwise, the easy-to-adhere polyester film and prints were obtained in the same manner as in Example 1.

[0223] As shown in Table 5, in Example 7, “BA”, “b” and “cb” respectively satisfy the range of the following formula, which can satisfy the anti-adhesion property.

[0224] (i) 0.5 ≤ BA(at%) ≤ 3.0

[0225] (ii) 30 ≤ b (seconds) ≤ 180

[0226] (iii) 30 ≤ cb (seconds) ≤ 300

[0227] Furthermore, "X" satisfies the following formula, ensuring excellent adhesion to each ink layer. This further demonstrates its superior adhesion, especially during low-radiation-dose processing and high-speed printing, to UV-curable inks.

[0228] (iv) 2.0 ≤ X (%) ≤ 10.0

[0229] Furthermore, it was confirmed that compared with Examples 1 to 6, which used polyester granules P-1, the haze value was lower and the transparency of the film was improved.

[0230] (Experimental Example 1)

[0231] The following coating agent was mixed in a mixed solvent of water and isopropanol to change the solid content ratio of polyurethane resin solution (A-5) / polyester aqueous dispersion (Cw-1) to 29 / 71, otherwise, an easy-to-adhere polyester film and print were obtained in the same manner as in Example 1.

[0232]

[0233] As shown in Table 5, in Experimental Example 1, the adhesion to each ink layer could not be satisfied because "X" was below 2.0%. Additionally, the anti-blocking property could not be satisfied because "b" exceeded 180 seconds.

[0234] (Experimental Example 2)

[0235] By changing the polyurethane resin to (A-4), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 1.

[0236] (Experimental Example 3)

[0237] By changing the polyurethane resin to (A-4) and the crosslinking agent to (B-2), an easy-to-adhere polyester film and print were obtained in the same manner as in Example 1.

[0238] As shown in Table 5, in Experiments 2 and 3, since “BA” is less than 0.5 at%, it cannot meet the requirement of adhesion to the solvent-based ink layer.

[0239] (Experimental Example 4)

[0240] The following coating agent was mixed in a mixed solvent of water and isopropanol to change the solid component ratio of polyurethane resin solution (A-4) / crosslinking agent (B-1) to 70 / 30. Otherwise, an easy-to-adhere polyester film and print were obtained in the same manner as in Example 1.

[0241]

[0242] As shown in Table 5, in Experiment 4, the haze requirement could not be met because "cb" exceeded 300 seconds.

[0243] (Experimental Example 5)

[0244] The following coating agent was mixed in a mixed solvent of water and isopropanol to change the solid component ratio of polyurethane resin solution (A-4) / crosslinking agent (B-1) to 20 / 80, otherwise, an easy-to-adhere polyester film and print were obtained in the same manner as in Example 1.

[0245]

[0246] As shown in Table 5, in Experiment 5, the haze requirement could not be met because "cb" exceeded 300 seconds.

[0247] (Experimental Example 6)

[0248] By changing the polyurethane resin to (A-2) and the crosslinking agent to (B-3), the same easy-to-adhere polyester film and print were obtained as in Example 5.

[0249] As shown in Table 5, in Experiment 6, since “BA” is less than 0.5 at%, it cannot meet the requirements for anti-blocking and adhesion to solvent-based ink layers.

[0250] (Experiment Example 7)

[0251] By changing the polyurethane resin to (A-6), otherwise the same easy-to-adhere polyester film and print were obtained as in Example 5.

[0252] As shown in Table 5, in Experiment 7, since “X” is less than 2.0%, it is impossible to meet the tightness with each ink layer.

[0253] The evaluation method used in this invention will be described below.

[0254] (1) Haze

[0255] The haze of the obtained easy-to-adhere polyester film was measured according to JIS K 7136:2000 using a turbidimeter (Nippon Denshoku Corporation, NDH5000).

[0256] (2) Anti-adhesion

[0257] Two thin film samples were overlapped with their coating layers facing each other, a load of 98 kPa was applied, and they were sealed and placed at 50°C for 24 hours. Then, the films were peeled off, and their peeling condition was determined using the following criteria.

[0258] ○: The coating layer has minimal transfer and can be easily peeled off.

[0259] △: The coating layer was maintained, but the surface of the coating layer was partially transferred to the opposite side.

[0260] ×: Two films are stuck together and cannot be peeled off, or even if they can be peeled off, the film substrate is cracked.

[0261] (3) Fit

[0262] For the ink layer of the obtained print, 100 square cuts were made through the ink layer and reaching the substrate film using a 2mm gap cutter guide. Next, cellophane tape (made by NICHIBAN CO.,LTD., No. 405; 24mm width) was applied to the square cut surfaces and rubbed with an eraser to ensure complete adhesion. Then, the cellophane tape was peeled off vertically five times from the ink layer of the easily bondable polyester film with the stacked ink layer. The number of squares peeled off from the ink layer of the print was visually counted, and the adhesion between the ink layer and the film substrate was calculated using the following formula. It should be noted that partially peeled squares are also counted as peeled squares. An adhesion of 95% or higher is considered acceptable.

[0263] Adhesion (%) = (1 - number of squares peeled off / 100) × 100

[0264] (4) Determination of elemental distribution in the depth direction

[0265] The elemental distribution along the depth direction of the coating layer was determined using X-ray photoelectron spectroscopy (ESCA). An Ar cluster beam, which is expected to be low-damaging for organic materials, was used as the ion source for etching. Furthermore, the sample was rotated during etching to ensure uniform etching. To minimize X-ray irradiation-based damage, spectral data collection at each etching time was performed using a snapshot mode that allows for short-term evaluation. For ease of evaluation, spectral data collection was performed every 30 seconds until the etching time reached 120 seconds, and then every 60 seconds thereafter. Details of the measurement conditions are shown below. It should be noted that background removal was performed using the Shirley method during resolution.

[0266] • Device: K-Alpha+ (manufactured by Thermo Fisher Scientific)

[0267] • Measurement conditions

[0268] Excitation of X-rays: Monochromatic AlKα rays

[0269] X-ray output: 12kV, 2.5mA

[0270] Photoelectron escape angle: 90°

[0271] Spot size: 200μmφ

[0272] Pass energy: 150eV (snapshot mode)

[0273] Accelerating voltage of the ion gun: 6kV

[0274] Bundle size: Large

[0275] Etching rate: 10 nm / min (converted from polystyrene) ※

[0276] Sample rotation during etching:

[0277] (The etching rate was calculated using a 155 nm thick film fabricated on a silicon wafer by dissolving monodisperse polystyrene with a molecular weight of 91000 (Mw / Mn = 1.05) in toluene.)

[0278] Based on the data from this evaluation, the etching time of the self-coated layer surface was used as the horizontal axis, and the ratio of the amount of nitrogen atoms to the total amount of carbon, oxygen, nitrogen, and silicon atoms (nitrogen atom ratio) was used as the vertical axis to plot a nitrogen distribution curve. The nitrogen distribution curves of the easily bondable polyester film samples (Examples 2, 5, and Experimental Example 6) described later are shown below. Figure 1 , 3 4. Based on Figure 1 The nitrogen distribution curve of Example 2 shown is obtained by using... Figure 2 The method for determining the characteristic values ​​of this invention will be explained. For example... Figure 2 As shown, the nitrogen atom ratio on the coating surface opposite to the polyester film substrate is read as A (at%), the maximum nitrogen atom ratio is set as B (at%), the etching time when the nitrogen atom ratio is at its maximum value B (at%) is read as b (seconds), and the etching time when the nitrogen atom ratio becomes 1 / 2 B (at%) after b (seconds) is read as c (seconds). BA (at%) and cb (seconds) are then calculated. The nitrogen atom ratio on the coating surface opposite to the polyester film substrate refers to the nitrogen atom ratio at etching time 0 (seconds) in the figure. (It should be noted that...) Figures 1-4 The horizontal axis in the figure is recorded as "etching time s," where "s" refers to the unit "second."

[0279] (5) Determination of the OCOO bond ratio in the surface region

[0280] The ratio (X) of OCOO bonds in the surface region was evaluated using X-ray photoelectron spectroscopy (ESCA). The apparatus used was K-Alpha+ (Thermo Fisher Scientific). Details of the measurement conditions are shown below. It should be noted that background removal was performed using the Shirley method during analysis. Furthermore, X was calculated as the average of measurements from three or more sites.

[0281] • Measurement conditions

[0282] Excitation of X-rays: Monochromatic AlKα rays

[0283] X-ray output: 12kV, 6mA

[0284] Photoelectron escape angle: 90°

[0285] Spot size:

[0286] Pass energy: 50eV

[0287] Stride length: 0.1 eV

[0288] Energy resolution: FWHM of Ag3d(5 / 2) spectrum = 0.75 eV

[0289] Figure 5 , 6 This is a graph showing the analytical results of the C1s spectra of the surface regions of the easily bondable polyester films of Example 6 and Experimental Example 1, respectively. The gray solid line represents the measured data of the C1s spectra. The peaks of the obtained measured spectra were separated into multiple peaks, and the bond types corresponding to each peak were identified by the position and shape of each peak. Then, curve fitting was performed using the peaks derived from each bond type, and the peak area was calculated. The bond types of each possible peak (1) to (6) are shown in Table 3.

[0290] [Table 3]

[0291] Key species (1) Black two-dot dashed line CC key (2) Black dashed line CO bond, CN bond (3) Black three-dot dashed line C=O bond (4) Black dotted line COO key (5) Black dashed line OCOO key (6) Black solid line π-π* bond

[0292] The total peak area originating from each bond in the C1s spectral region refers to the total peak area of ​​peaks (1) to (6), and the peak area originating from the OCOO bond refers to the peak area of ​​peak (5). When the total peak area originating from each bond in the C1s spectral region is set to 100%, X(%) is expressed as the percentage of the area of ​​peak (5).

[0293] Table 4 shows the peak area calculation results for peaks (1) to (6) of Example 6 and Experimental Example 1. As mentioned above, the percentage data for peak (5) is X (%). Peaks (3) and (6) of Example 6, and peaks (3) and (5) of Experimental Example 1 did not appear.

[0294] [Table 4]

[0295] Example 6 Experimental Example 1 (1) 63.5％ 64.4％ (2) 23.1％ 20.9％ (3) - - (4) 7.5％ 12.7％ (5) 5.9％ - (6) - 2.0％

[0296] (6) Method for determining the number-average molecular weight of polycarbonate polyols

[0297] Proton nuclear magnetic resonance (¹H-NMR) spectroscopy was used to determine the polyurethane resin with a polycarbonate structure. A peak originating from the methylene group adjacent to the OCOO bond was observed near 4.1 ppm. Additionally, at a magnetic field approximately 0.2 ppm higher than this peak, a peak originating from the methylene group adjacent to the urethane bond formed during the reaction of the polyisocyanate with the polycarbonate polyol was observed. The number-average molecular weight of the polycarbonate polyol was calculated based on the integrated values ​​of these two peaks and the molecular weights of the monomers constituting the polycarbonate polyol.

[0298] Table 5 summarizes the evaluation results of each embodiment and experimental example.

[0299] [Table 5]

[0300]

[0301] Industrial availability

[0302] The easily bondable polyester film of this invention exhibits excellent adhesion to UV-curable inks, solvent-based inks, oxidative polymer inks, heat transfer ink tapes, and LBP toners. It is particularly suitable as a substrate film for various printed materials with good adhesion to UV-curable inks during low-radiation-dose processing or high-speed printing.

Claims

1. A printed matter which is obtained by laminating at least one ink layer selected from the group consisting of UV-curable ink, solvent-based ink, oxidatively polymerizable ink, thermal transfer ink ribbon, and LBP toner on a coating layer of an easy-adhesion polyester film having the coating layer on at least one side of a polyester film substrate, the coating layer is formed by curing a composition containing a polycarbonate-structure-containing polyurethane resin, a crosslinking agent, and a polyester resin, the polycarbonate-structure-containing polyurethane resin is obtained by polymerization of a polycarbonate polyol component and a polyisocyanate component, a mass ratio of the polycarbonate polyol component to the polyisocyanate component, i.e., mass of polycarbonate polyol component / mass of polyisocyanate component, is in the range of 0.5 to 2.5, a number average molecular weight of the polycarbonate polyol component is 500 to 1800, a content of a solid component of the crosslinking agent is 10 to 50 mass% when a total of solid components of the polyester resin, the polycarbonate-structure-containing polyurethane resin, and the crosslinking agent in the composition is set to 100 mass%, the crosslinking agent is a blocked isocyanate having 3 or more isocyanate groups, in a distribution curve of nitrogen element determined by elemental distribution measurement in a depth direction based on X-ray photoelectron spectroscopy with respect to the coating layer, when a nitrogen atomic ratio of a coating layer surface on the opposite side to the polyester film substrate is set to A (at%), a maximum value of the nitrogen atomic ratio is set to B (at%), an etching time at which the nitrogen atomic ratio shows the maximum value B (at%) is set to b (sec), an etching time at which the nitrogen atomic ratio becomes 1 / 2 B (at%) after b (sec) is set to c (sec), the following formulas (i) to (iii) are satisfied, and when a total of peak areas derived from each bond type in a Cls spectrum region in a surface analysis spectrum determined by X-ray photoelectron spectroscopy is set to 100 (%), a peak area derived from an OCOO bond is set to X (%), the following formula (iv) is satisfied, (i) 0.5 < B - A (at%) < 3.0 (ii) 30 < b (sec) < 180 (iii) 30 < c - b (sec) < 300 (iv) 2.0 < X (%) < 10.

0.

2. The printed matter according to claim 1, wherein a haze of the easy-adhesion polyester film is 1.5 (%) or less.

3. The printed matter according to claim 1 or 2, wherein a thickness of the coating layer is in the range of 0.001 to 2.00 μm.

4. The printed matter according to claim 1, wherein the following formulas (i) to (iv) are satisfied, (i) 0.6 < B - A (at%) < 2.8 (ii) 30 < b (sec) < 120 (iii) 30 < c - b (sec) < 240 (iv) 2.5 < X (%) < 9.

0.

5. The printed matter according to claim 1, wherein the polyisocyanate component is at least one selected from the group consisting of alicyclic diisocyanate, aliphatic diisocyanate, and a polyisocyanate obtained by preliminarily adding trimethylolpropane to these compounds in a single or plural number.

6. The printed matter according to claim 1, wherein The polyisocyanate component is at least one selected from the group consisting of xylylene diisocyanate and polyisocyanates obtained by previously adding xylylene diisocyanate to trimethylolpropane in a single or plural number.

7. The printed matter according to claim 1 or 2, wherein The ink layer is at least one layer selected from the group consisting of light-resistant UV-curable ink, UV-curable screen ink, solvent ink, oxidation polymerization ink, thermal transfer ink ribbon, and LBP toner.

8. A production method, which is a method of producing the printed matter according to claim 1, comprising: (1) a step of forming a coating layer by applying a coating liquid containing a composition to at least one side of a polyester film substrate, the composition containing a polycarbonate-structure-containing polyurethane resin, a crosslinking agent, and a polyester resin, the polycarbonate-structure-containing polyurethane resin is obtained by polymerization of a polycarbonate polyol component and a polyisocyanate component, the mass ratio of the polycarbonate polyol component to the polyisocyanate component, i.e., the mass of the polycarbonate polyol component / the mass of the polyisocyanate component, is in the range of 0.5 to 2.5, the number average molecular weight of the polycarbonate polyol component is 500 to 1800, when the total of the solid components of the polyester resin, the polycarbonate-structure-containing polyurethane resin, and the crosslinking agent in the composition is taken as 100% by mass, the content of the solid component of the crosslinking agent is 10 to 50% by mass, the crosslinking agent is a blocked isocyanate having 3 or more isocyanate groups; and (2) a step of laminating an ink layer selected from at least one of UV-curable ink, solvent ink, oxidation polymerization ink, thermal transfer ink ribbon, and LBP toner on the coating layer.

9. The manufacturing method according to claim 8, wherein, The polyisocyanate component is at least one selected from the group consisting of alicyclic diisocyanate, aliphatic diisocyanate, and polyisocyanates obtained by previously adding these compounds to trimethylolpropane in a single or plural number.

10. The manufacturing method according to claim 8, wherein, The polyisocyanate component is at least one selected from the group consisting of xylylene diisocyanate and polyisocyanates obtained by previously adding xylylene diisocyanate to trimethylolpropane in a single or plural number.

11. The manufacturing method according to claim 8, wherein, When the total of the solid components of the polyester resin, the polycarbonate-structure-containing polyurethane resin, and the crosslinking agent in the coating liquid is taken as 100% by mass, the content of the polycarbonate-structure-containing polyurethane resin is 5 to 50% by mass.

12. The manufacturing method of claim 8, wherein, The blocked isocyanate having 3 or more isocyanate groups has a hydrophilic group.

13. The manufacturing method of claim 8, wherein, When the total of the solid components of the polyester resin, the polycarbonate-structure-containing polyurethane resin, and the crosslinking agent in the coating liquid is taken as 100% by mass, the content of the polyester resin is 10 to 70% by mass.

14. The manufacturing method of claim 8, wherein, The ink layer is at least one layer selected from the group consisting of light-resistant UV-curable ink, UV-curable screen ink, solvent ink, oxidation polymerization ink, thermal transfer ink ribbon, and LBP toner.

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