CN115803198A - Printed matter - Google Patents

Abstract

Provided is a printed matter using an easily adhesive polyester film which has high transparency, blocking resistance, and good adhesion to various ink compositions, particularly to a UV-curable ink during low-dose processing or high-speed printing. A printed matter having specific characteristics, which is obtained by laminating at least 1ink layer selected from a group consisting of UV-curable ink, solvent-based ink, oxidative polymerization ink, thermal transfer ink ribbon and LBP toner on an easy-adhesion polyester film having a coating layer on at least one surface of a polyester film substrate, wherein the coating layer is obtained by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent and a polyester resin.

Description

Printed matter

Technical Field

The present invention relates to a printed matter having excellent adhesion to various ink layers. More specifically, the present invention relates to a printed matter having a coating layer which is most suitable for easy adhesion of all kinds of ink layers such as Ultraviolet (UV) curable ink, solvent-based ink, oxidative polymerization ink, thermal transfer ribbon, LBP toner, and the like.

Background

Biaxially stretched polyester films are widely used for various industrial material applications, consumer applications, and the like because of their mechanical strength, heat resistance, chemical resistance, dimensional stability, and price balance. In particular, it is indispensable to apply printing to a transparent film for various commercial printing applications, decorative sheets, packaging cans, labels, and the like. However, since the adhesion between the polyester film and the printing ink is generally poor, an anchor coating layer using a resin having easy adhesion is generally provided. Among them, it has been proposed to use a water-soluble or water-dispersible polyester resin or acrylic resin for a film having a relatively high polarity, mainly polyester (see, for example, patent documents 1,2, 3 and 4). However, the polyester-based resin has disadvantages that blocking resistance in a film roll state is easily deteriorated and adhesiveness of the acrylic resin to a base film and a printing ink is easily deteriorated. Therefore, in order to improve these, it has been proposed to use the polyester resin in combination with the acrylic resin (see, for example, patent document 5). Further, various modified polyesters mainly based on graft modification have been proposed. In addition, disclosed are: a resin obtained by grafting an unsaturated bond-containing compound to a hydrophilic group-containing polyester resin which is water-soluble or water-dispersible is suitable as an anchor coating agent for a polyester film (see, for example, patent documents 6, 7, and 8). However, the adhesive properties and water resistance are still insufficient. Further, a graft-modified polyester resin is disclosed (for example, see patent documents 9 and 10), but because of lack of aggregating power, there is a problem in terms of peeling, scratching, and the like.

These problems are associated with fatal defects that cause generation of scratch scratches, peeling of coating/lubricant particles, and transfer failure/peeling of ink in printing applications. In particular, in the case of the offset sheet printing, strong friction is applied during feeding and transportation, and high adhesiveness is required by using a UV curable ink, which is an essential characteristic.

In recent years, in the printing industry, printing speed has been increased for the purpose of improving productivity. In the speeding-up of printing using UV curable ink, the time required from ink application to UV irradiation and the amount of UV accumulated light decrease. That is, the interaction of the ink with the polyester film and with the coating layer becomes weak. Therefore, the coating layer is required to have higher adhesion to the UV curable ink.

Documents of the prior art

Patent literature

Patent document 1: japanese laid-open patent publication No. Sho 54-43017

Patent document 2: japanese examined patent publication No. 49-10243

Patent document 3: japanese patent laid-open No. S52-19786

Patent document 4: japanese patent laid-open publication No. S52-19787

Patent document 5: japanese patent laid-open publication No. 58-124651

Patent document 6: japanese unexamined patent publication No. 2-3307

Patent document 7: japanese laid-open patent publication No. 2-171243

Patent document 8: japanese laid-open patent publication No. 2-310048

Patent document 9: japanese laid-open patent publication No. 3-273015

Patent document 10: japanese patent laid-open publication No. 3-67626

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a printed matter using an easy-adhesion polyester film which has high transparency and blocking resistance, has good adhesion to various ink compositions, and particularly has good adhesion to various ink compositions typified by UV-curable inks at the time of low-dose processing or high-speed printing.

Means for solving the problems

In order to solve the above problems, the present inventors have found, in the course of research on the causes of the above problems and the like: the present invention has been accomplished by providing a polyester film substrate with a coating layer on at least one surface thereof, the coating layer containing a crosslinking agent, a polyurethane resin having a polycarbonate structure, and a polyester resin, and by solving the problems of the present invention when the ratio of nitrogen atoms in the coating layer and the ratio of OCOO bonds on the surface of the coating layer on the opposite side of the polyester film substrate satisfy specific conditions.

The above-described problems can be solved by the following means.

1. A printed matter comprising a polyester film base and, superimposed thereon, an easily adhesive polyester film having a coating layer on at least one surface thereof, at least 1ink layer selected from the group consisting of UV-curable inks, solvent-based inks, oxidative polymerization inks, thermal transfer ribbons and LBP toners,

the coating layer is formed by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent and a polyester resin,

in a distribution curve of nitrogen element in the coating layer measured based on the element distribution in the depth direction of the X-ray photoelectron spectroscopy, when the nitrogen atom ratio of the surface of the coating layer on the opposite side of the polyester film substrate is A (at%), the maximum value of the nitrogen atom ratio is B (at%), the etching time at which the nitrogen atom ratio shows the maximum value B (at%) is B (second), and the etching time at which the nitrogen atom ratio becomes 1/2B (at%) after B (second) is C (second), the following formulas (i) to (iii) are satisfied, and in a surface analysis spectrum measured by the X-ray photoelectron spectroscopy, the following formula (iv) is satisfied when the total of the peak areas derived from the respective bonding species in the C1s spectrum region is 100 (%), and the peak area derived from the OCOO bond is X (%),

(i)0.5≤B-A(at％)≤3.0

(ii) B is more than or equal to 30 and less than or equal to 180 in second

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

(iv)2.0≤X(％)≤10.0。

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

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, various printed matters having good adhesion between the base material and the ink layer can be obtained. Particularly, the ink composition has good adhesion to various ink compositions typified by UV curable inks in low-dose processing or high-speed printing. Further, the easy-adhesion polyester film of the present invention has high transparency and excellent blocking resistance.

Drawings

Fig. 1 is a nitrogen element distribution curve based on the element distribution measurement in the depth direction by the X-ray photoelectron spectroscopy method for the easy-adhesion polyester film of example 2.

FIG. 2 is an explanatory view for obtaining B-A, B, and c-B from ase:Sub>A distribution curve of nitrogen element based on the measurement of element distribution in the depth direction by X-ray photoelectron spectroscopy.

Fig. 3 is a nitrogen element distribution curve based on the element distribution measurement in the depth direction by the X-ray photoelectron spectroscopy with respect to the easy-adhesion polyester film of example 5.

Fig. 4 is a distribution curve of nitrogen element measured based on element distribution in the depth direction by X-ray photoelectron spectroscopy with respect to the easy-adhesion polyester film of experimental example 6.

Fig. 5 is a graph showing the analysis result of the C1s spectrum of the surface region of the coating layer of the easy-adhesion polyester film of example 6.

Fig. 6 is a graph showing the analysis result of the C1s spectrum of the surface region of the coating layer of the easy-adhesion polyester film of experimental example 1.

Detailed Description

(polyester film substrate)

In the present invention, the polyester resin constituting the polyester film base material is a copolymerized polyester resin obtained by substituting a part of the diol component or the dicarboxylic acid component of the polyester resin described above with a copolymerized component such as diethylene glycol, neopentyl glycol, 1, 4-cyclohexanedimethanol, or polyalkylene glycol, or a dicarboxylic acid component such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, sodium 5-isophthalate, or 2, 6-naphthalenedicarboxylic acid, in addition to polyethylene terephthalate, polybutylene terephthalate, polyethylene-2, 6-naphthalenedicarboxylate, or polypropylene terephthalate.

The polyester resin which can be suitably used in the present invention is mainly selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene-2, 6-naphthalate. Among these polyester resins, polyethylene terephthalate is most preferable in terms of balance between physical properties and cost. The polyester film base material made of these polyester resins is preferably a biaxially stretched polyester film, and can improve chemical resistance, heat resistance, mechanical strength, and the like.

The catalyst for polycondensation used in the production of the polyester resin is not particularly limited, but antimony trioxide is preferred because it is an inexpensive catalyst having excellent catalytic activity. Further, a germanium compound or a titanium compound is preferably used. Further preferable polycondensation catalysts include a catalyst containing aluminum and/or a compound thereof and a phenolic compound, a catalyst containing aluminum and/or a compound thereof and a phosphorus compound, and a catalyst containing an aluminum salt of a phosphorus compound.

The polyester film substrate in the present invention may be a single-layer polyester film, may be composed of 2 layers having different components, or may be a polyester film substrate composed of at least 3 layers having an outer layer and an inner layer.

(description of characteristic values in the invention)

The easy-to-adhere polyester film of the present invention is preferably one having a coating layer on at least one surface of a polyester film substrate as described above. The coating layer is obtained by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent and a polyester resin. Here, the expression "the composition is cured" is used because: it is extremely difficult to accurately express the chemical composition of the state in which the polyurethane resin having a polycarbonate structure, the crosslinking agent, and the polyester resin are cured by the crosslinking agent forming a crosslinked structure. In addition, when the maximum value of the distribution curve of the nitrogen element in the depth direction of the coating layer measured based on the element distribution is present in the vicinity of the surface of the coating layer on the opposite side to the polyester film substrate, it is preferable that the transparency and the blocking resistance can be improved. Further, when a proper amount of polycarbonate structure is present on the surface of the coating layer on the side opposite to the polyester film substrate, it is preferable to improve the UV ink adhesion during low-dose processing and high-speed printing.

The characteristics of the coating layer in the above-mentioned easy-adhesion polyester film will be described. First, a distribution curve of nitrogen elements based on the element distribution measurement in the depth direction of the coating layer was plotted by X-ray photoelectron spectroscopy (ESCA). That is, the pattern collection was performed every 30 seconds until the etching time reached 120 seconds, and then every 60 seconds. As shown in fig. 2, the horizontal axis represents the etching time (unit: second) from the surface of the coating layer, the vertical axis represents the ratio of the amount of nitrogen atoms to the total amount of carbon atoms, oxygen atoms, nitrogen atoms, and silicon atoms (nitrogen atom ratio, unit: at%), the etching time when the nitrogen atom ratio of the coating layer surface on the opposite side of the polyester film substrate is a (at%), the maximum value of the nitrogen atom ratio is B (at%), and the etching time when the nitrogen atom ratio becomes 1/2B (at%) after B (second) is c (second). B-A (at%), c-B (sec) was calculated from the read datase:Sub>A. The nitrogen atom ratio A (at%) of the surface of the coating layer on the opposite side of the polyester film substrate was the nitrogen atom ratio at the time of etching time 0 (second).

Further, when the characteristic values read from the distribution curve of nitrogen element measured based on the element distribution in the depth direction of the coating layer are in the following relationship, an easily adhesive polyester film excellent in transparency, blocking resistance, and adhesion to the solvent-based ink layer can be obtained.

(i)0.5≤B-A(at％)≤3.0

(ii) B is more than or equal to 30 and less than or equal to 180 in second

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

The lower limit of B-A is preferably 0.5at%, more preferably 0.6at%, still more preferably 0.7at%, particularly preferably 0.8at%, most preferably 0.9at%. When the amount is 0.5at% or more, the amount of the urethane resin component having toughness is sufficient, blocking resistance can be obtained, and adhesion to the solvent-based ink layer is excellent. The upper limit of B-A is preferably 3.0at%, more preferably 2.9at%, still more preferably 2.8at%, particularly preferably 2.7at%, most preferably 2.5at%. When the content is 3.0at% or less, the haze is low, and transparency can be obtained.

The lower limit of b is preferably 30 seconds, and when it is 30 seconds or more, it is preferable to maintain the toughness of the surface of the coating layer on the opposite side to the polyester film substrate, and to obtain the blocking resistance. The upper limit of b is preferably 180 seconds, more preferably 120 seconds, further preferably 90 seconds, particularly preferably 60 seconds. When the amount is 180 seconds or less, the toughness of the surface of the coating layer on the side opposite to the polyester film substrate is maintained, and the blocking resistance is preferably good.

The upper limit of c-b is preferably 300 seconds, more preferably 240 seconds, and further preferably 180 seconds. When the amount is 300 seconds or less, the urethane resin component in the coating layer is not excessively increased, and the haze is low and transparency can be obtained. The lower limit of c-b is 30 seconds or more because the spectrum collection is every 30 seconds from the start of measurement to 120 seconds of etching time.

In the present invention, it is preferable that the polycarbonate moiety in the polyurethane resin in the coating layer constituting the easy-adhesion polyester film is localized in many parts on the surface of the coating layer on the opposite side to the polyester film substrate. This is because adhesion to various ink compositions is improved by allowing an appropriate amount of polycarbonate moieties to be present on the surface. On the other hand, it has also been found that: when a polycarbonate structural part is present on the surface, flexibility may be increased and blocking resistance may not be sufficient. Therefore, as described above, when the characteristic values read from the distribution curve of nitrogen element measured based on the element distribution in the depth direction of the coating layer are in the following relationship, an easily adhesive polyester film having excellent transparency and blocking resistance can be obtained.

(i)0.5≤B-A(at％)≤3.0

(ii) B (second) is more than or equal to 30 and less than or equal to 180

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

In the easy-adhesion polyester film of the present invention, as a means for satisfying the above-mentioned formulas (i) to (iii), in the synthesis and polymerization of a polyurethane resin having a polycarbonate structure forming the coating layer, the polyurethane resin is synthesized and polymerized while containing 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 the content of the solid content of the crosslinking agent is 10 to 50% by mass when the total of the solid contents of the polyester resin, the polyurethane resin and the crosslinking agent in the coating solution is 100% by mass. Further, by using ase:Sub>A blocked isocyanate as ase:Sub>A crosslinking agent and using ase:Sub>A blocked isocyanate having an isocyanate group of 3 or more functions, efficient adjustment of B-ase:Sub>A can be achieved.

As described above, it is preferable that the polycarbonate moiety in the polyurethane resin in the coating layer in the present invention is present in a large amount on the surface of the coating layer opposite to the polyester film substrate. In the present invention, the total peak area of each bond species derived from the C1s spectrum region in the surface analysis spectrum measured by X-ray photoelectron spectroscopy is defined as 100 (%), and the peak area derived from the OCOO bond (as a polycarbonate structure) is defined as X (%), and these are expressed as percentages.

Here, the ratio X (%) of OCOO bonds (in a polycarbonate structure) in the surface region was evaluated by X-ray photoelectron spectroscopy (ESCA). Fig. 5 and 6 are examples of graphs showing the results of analysis of C1s spectra of the surface regions of the easy-adhesive polyester films of example 6 and experimental example 1, which will be described later. The solid gray line represents the measured data of the C1s profile. The peak of the obtained actual measurement pattern is separated into a plurality of peaks, and the bond species corresponding to each peak is identified based on the position and shape of each peak. Further, curve fitting is performed with peaks derived from various bond species, and the peak area can be calculated. The coating layer in the present invention contains: a polyurethane resin having a polycarbonate structure, a crosslinking agent represented by a blocked isocyanate having an isocyanate group having a 3-or more functional group, and a polyester resin, and in the case of the coating layer, peaks of the bond species of peaks (1) to (6) in table 1 can be detected. The bond species of peaks (1) to (6) in table 1 are not limited to those shown in table 1, and may include similar bond species in a trace amount. Here, in fig. 5 related to example 6, the C = O bond peak of (3) and the pi-pi x binding peak of (6) of table 1 are not shown. In fig. 6 related to experimental example 1, the C = O bond peak of (3) and the OCOO bond peak of (5) in table 1 are not shown. The ratio X (%) of the OCOO bonds in the surface region is a value represented by a percentage (%) of the area ratio of the peak (5) when the total of the peak areas of the peaks (1) to (6) is 100%.

[ Table 1]

	Key seed
		(1) Black two-dot dotted line	A C-C bond
(2) Black dotted line	C-O bond, C-N bond
		(3) Black three dotted line	C = O bond
(4) Black dotted line	COO bond
		(5) Black dotted line	OCOO key
(6) Solid black line	Pi-pi bonds

Suitable ranges of the peak area X (%) derived from the OCOO bond are as follows. The lower limit of X is preferably 2.0%, more preferably 2.5%, further preferably 3.0%, particularly preferably 3.5%, most preferably 4.0%. When the content is 2.0% or more, the ink adhesion can be effectively satisfied, which is preferable. The upper limit of X is preferably 10.0%, more preferably 9.0%, further preferably 8.0%, particularly preferably 7.5%, most preferably 7%. When the content is 10.0% or less, the flexibility of the skin layer is not excessively high, and the blocking resistance is easily obtained.

In the method for producing an easily adhesive polyester film according to the present invention, it is preferable that the mass ratio of the polycarbonate polyol component to the polyisocyanate component in the synthesis and polymerization of the polyurethane resin having a polycarbonate structure forming the coating layer is 0.5 or more, and the content of the polyurethane resin is 5 to 50% by mass when the total of the polyester resin, the polyurethane resin having a polycarbonate structure and the solid content of the crosslinking agent in the coating liquid is 100% by mass, because the X characteristic value based on the C1s spectrum region can be effectively achieved in the range of 2.0 to 10.0%.

(coating layer)

The easy-adhesion polyester film of the present invention is preferably: in order to improve adhesion to the ink layer, a coating layer formed from a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin is laminated on at least one surface of 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 with different kinds of resin coating layers on the other side.

The respective compositions of the coating layer will be described in detail below.

(polyurethane resin)

The polyurethane resin having a polycarbonate structure in the present invention has at least urethane bond portions derived from a polycarbonate polyol component and a polyisocyanate component, and further contains a chain extender as necessary.

The lower limit of the mass ratio of the polycarbonate polyol component to the polyisocyanate component (mass of polycarbonate polyol component/mass of polyisocyanate component) during synthesis and polymerization of the polyurethane resin having a polycarbonate structure in the present invention is preferably 0.5, more preferably 0.6, even more preferably 0.7, particularly preferably 0.8, and most preferably 1.0. When the content is 0.5 or more, the content X of the OCOO bonds on the surface of the coating layer can be adjusted to 2% or more with high efficiency. The upper limit of the mass ratio of the polycarbonate polyol component to the polyisocyanate component in the synthesis and polymerization of the polyurethane resin having a polycarbonate structure in the present invention is preferably 2.5, more preferably 2.2, still more preferably 2.0, particularly preferably 1.7, and most preferably 1.5. When the content is 2.5 or less, the content X of the OCOO bond on the surface of the coating layer can be preferably adjusted to 10% or less with high efficiency. Further, in the nitrogen distribution curve measured based on the element distribution in the depth direction by the X-ray photoelectron spectroscopy, B-A can be effectively adjusted to 0.5at% or more, and c-B can be effectively adjusted to 300 seconds or less.

The polycarbonate polyol component used for synthesizing and polymerizing the polyurethane resin having a polycarbonate structure in the present invention preferably contains an aliphatic polycarbonate polyol having excellent heat resistance and hydrolysis resistance. The aliphatic polycarbonate polyol includes aliphatic polycarbonate diol, aliphatic polycarbonate triol and the like, and aliphatic polycarbonate diol can be suitably used. Examples of the aliphatic polycarbonate diol used for synthesizing and polymerizing the polyurethane resin having a polycarbonate structure in the present invention include: aliphatic polycarbonate diols obtained by reacting 1 or 2 or more kinds of diols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, 1, 9-nonanediol, 1, 8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, and the like with carbonates such as dimethyl carbonate, ethylene carbonate, phosgene, and the like.

The number average molecular weight of the polycarbonate polyol in the present invention is preferably 500 to 1800. More preferably 600 to 1700, most preferably 700 to 1500. When the content is 500 or more, the content X of the OCOO bond on the surface of the coating layer can be effectively adjusted to 10% or less, which is preferable. When the nitrogen concentration is 1800 or less, it is preferable that B-A be effectively adjusted to 0.5 or more and c-B be effectively adjusted to 300 seconds or less in ase:Sub>A nitrogen distribution curve measured based on the element distribution in the depth direction by X-ray photoelectron spectroscopy.

Examples of the polyisocyanate used for synthesizing and polymerizing the polyurethane resin having a polycarbonate structure in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, 4-dicyclohexylmethane diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2, 4-trimethylhexamethylene diisocyanate, and polyisocyanates obtained by previously adding one or more compounds thereof to trimethylolpropane or the like. When the aromatic aliphatic diisocyanate, the alicyclic diisocyanate, the aliphatic diisocyanate, or the like is used, the yellowing problem does not occur, and the use is preferable. Further, it is preferable that the coating film is not excessively hard, and stress due to thermal shrinkage of the polyester film substrate can be relaxed to improve adhesiveness.

Examples of the chain extender include: glycols such as ethylene glycol, diethylene glycol, 1, 4-butanediol, neopentyl glycol and 1, 6-hexanediol; polyhydric alcohols such as glycerin, trimethylolpropane and pentaerythritol; diamines such as ethylenediamine, hexamethylenediamine, and piperazine; aminoalcohols such as monoethanolamine and diethanolamine; thiodiglycols such as thiodiglycol; or water.

The coating layer in the present invention is preferably formed by an in-line coating method described later using an aqueous coating liquid. Therefore, the polyurethane resin of the present invention is desired to have water solubility or water dispersibility. The term "water-soluble or water-dispersible" as used herein means that the water-soluble or water-dispersible resin is dispersed in water or an aqueous solution containing less than 50 mass% of a water-soluble organic solvent.

In order to impart water dispersibility to the polyurethane resin, a (co) sulfonic acid (salt) group or a carboxylic acid (salt) group may be introduced into the urethane molecular skeleton. In order to maintain moisture resistance, it is preferable to introduce a weakly acidic carboxylic acid (salt) group. Further, a nonionic group such as polyoxyalkylene group may be introduced.

In order to introduce a carboxylic acid (salt) group into the polyurethane resin, for example, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid or dimethylolbutyric acid is introduced as a polyol component, and neutralized with a salt forming agent. Specific examples of the salt-forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine and tri-n-butylamine; n-alkylmorpholines such as N-methylmorpholine and N-ethylmorpholine; n-dialkylalkanolamines such as N-dimethylethanolamine and N-diethylethanolamine. These can be used alone, can also be combined with 2 or more.

When a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component in order to impart water dispersibility, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the polyurethane resin is preferably 3 to 60 mol%, and preferably 5 to 40 mol%, based on 100 mol% of the total polyisocyanate component in the polyurethane resin. When the composition molar ratio is less than 3 mol%, water dispersibility may be difficult. When the composition molar ratio exceeds 60 mol%, the water resistance may be lowered, and the moist heat resistance may be lowered.

In order to improve the hardness, the polyurethane resin of the present invention may be terminally bonded with a blocked isocyanate.

(crosslinking agent)

In the present invention, the crosslinking agent contained in the coating layer-forming composition is preferably a blocked isocyanate, more preferably a blocked isocyanate having 3 or more functions, and particularly preferably a blocked isocyanate having 4 or more functions. The blocking resistance is improved by these. When the blocked isocyanate crosslinking agent is used, it is preferable that B-A can be efficiently adjusted to 0.5at% or more in ase:Sub>A nitrogen distribution curve measured based on the element distribution in the depth direction by X-ray photoelectron spectroscopy.

The lower limit of the boiling point of the blocking agent for blocking the isocyanate is preferably 150 ℃, more preferably 160 ℃, still more preferably 180 ℃, particularly preferably 200 ℃, and most preferably 210 ℃. The higher the boiling point of the end-capping agent, the more the end-capping agent is, the more the film transparency of the film can be improved by suppressing volatilization of the end-capping agent and suppressing generation of fine irregularities on the surface of the coating film even by thermal addition in the film forming step in the case of the drying step after coating with the coating liquid or in the case of the inline coating method. The upper limit of the boiling point of the end-capping agent is not particularly limited, and it is considered that about 300 ℃ is the upper limit in view of productivity. Since the boiling point is related to the molecular weight, it is preferable to use a blocking agent having a large molecular weight in order to increase the boiling point of the blocking agent, and the molecular weight of the blocking agent is preferably 50 or more, more preferably 60 or more, and further preferably 80 or more.

The upper limit of the dissociation temperature of the blocking agent is preferably 200 ℃, more preferably 180 ℃, further preferably 160 ℃, particularly preferably 150 ℃, and most preferably 120 ℃. In the case of the drying step after coating of the coating liquid or the in-line coating method, the blocking agent is dissociated from the functional group by heat addition in the film forming step to generate a regenerated isocyanate group. Therefore, a crosslinking reaction with the urethane resin or the like proceeds, and the adhesiveness is improved. When the dissociation temperature of the blocked isocyanate is not higher than the above temperature, dissociation of the blocking agent proceeds sufficiently, and thus adhesiveness, particularly moist heat resistance, is improved.

Examples of the blocking agent having a dissociation temperature of the blocked isocyanate of 120 ℃ or lower and a boiling point of the blocking agent of 150 ℃ or higher in the present invention include bisulfite compounds: sodium bisulfite and the like; pyrazole compounds: 3, 5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3, 5-dimethylpyrazole, 4-nitro-3, 5-dimethylpyrazole, or the like; an active methylene group: malonic acid diester (dimethyl malonate, diethyl malonate, di-n-butyl malonate, di-2-ethylhexyl malonate), methyl ethyl ketone, and the like; triazole-based compound: 1,2, 4-triazole, and the like. Among them, a pyrazole compound is preferable from the viewpoint of moist heat resistance and yellowing.

The polyisocyanate used as the precursor of the blocked isocyanate in the present invention can be obtained by introducing a diisocyanate. Examples thereof include urethane-modified products, allophanate-modified products, urea-modified products, biuret-modified products, uretdione-modified products, uretonimine-modified products, isocyanurate-modified products, and carbodiimide-modified products of diisocyanates.

<xnotran> , 2,4- ,2,6- ,4,4 '- ,2,4' - ,2,2 '- ,1,5- ,1,4- , , ,4,4' - ,2- -4,4'- ,2,2' - -4,4'- ,3,3' - -4,4'- ,4,4' - ,3,3 '- -4,4' - ; </xnotran> Aromatic aliphatic diisocyanates such as xylylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, 4-dicyclohexylmethane diisocyanate, and 1, 3-bis (isocyanatomethyl) cyclohexane; aliphatic diisocyanates such as hexamethylene diisocyanate and 2, 4-trimethylhexamethylene diisocyanate. From the viewpoint of transparency, adhesiveness, and moist heat resistance, aliphatic, alicyclic isocyanates and modified products thereof are preferable, and optical applications requiring less yellowing and high transparency are preferable.

In the blocked isocyanate of the present invention, a hydrophilic group may be introduced into the polyisocyanate as a precursor in order to impart water solubility or water dispersibility. Examples of the hydrophilic group include (1) quaternary ammonium salts of dialkylamino alcohols, quaternary ammonium salts of dialkylaminoalkylamines, and the like, (2) sulfonates, carboxylates, phosphates, and the like, (3) polyethylene glycols, polypropylene glycols, and the like, each of which is singly terminated with an alkoxy group. When a hydrophilic site is introduced, the polymer is (1) cationic, (2) anionic, or (3) nonionic. Among them, most of the other water-soluble resins are anionic, and therefore, anionic and nonionic resins which can be easily compatible are preferable. Further, the anionic resin is excellent in compatibility with other resins, and the nonionic resin does not have an ionic hydrophilic group, and therefore, it is also preferable for improving the moist heat resistance.

The anionic hydrophilic group is preferably one having a hydroxyl group for introducing into the polyisocyanate and a carboxylic acid group for imparting hydrophilicity. Examples thereof include glycolic acid, lactic acid, tartaric acid, citric acid, hydroxybutyric acid, hydroxypentanoic acid, hydroxypivalic acid, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, and polycaprolactone having a carboxylic acid group. For neutralizing carboxylic acid groups, organic amine compounds are preferred. Examples thereof include linear or branched primary, secondary or tertiary amines having 1to 20 carbon atoms such as ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine and ethylenediamine, cyclic amines such as morpholine, N-alkylmorpholine and pyridine, monoisopropanolamine, methylethanolamine, methylisopropanolamine, dimethylethanolamine, diisopropanolamine, diethanolamine, triethanolamine, diethylethanolamine and triethanolamine.

The repeating unit of ethylene oxide and/or propylene oxide of polyethylene glycol or polypropylene glycol obtained by single capping with an alkoxy group is preferably 3 to 50, more preferably 5 to 30, as the nonionic hydrophilic group. When the repeating unit is small, the compatibility with the resin is poor, and the haze is high, and when the repeating unit is large, the adhesiveness under high temperature and high humidity is sometimes low. The blocked isocyanate of the present invention may be added with a nonionic, anionic, cationic or amphoteric surfactant to improve water dispersibility. Examples thereof include nonionic surfactants such as polyethylene glycol and polyol fatty acid esters, anionic surfactants such as fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonate salts, sulfosuccinate salts and alkyl phosphate salts, cationic surfactants such as alkylamine salts and alkylbetaine, and surfactants such as carboxylate amine salts, sulfonate amine salts and sulfate ester salts.

In addition to water, a water-soluble organic solvent may be contained. For example, the organic solvent used in the reaction may be added, or another organic solvent may be added after removing it.

(polyester resin)

The polyester resin for forming the coating layer in the present invention may be a linear polyester resin, and more preferably a polyester resin containing a dicarboxylic acid and a branched diol as constituent components. The dicarboxylic acid used herein includes aliphatic dicarboxylic acids such as adipic acid and sebacic acid, in addition to terephthalic acid, isophthalic acid, and 2, 6-naphthalenedicarboxylic acid as main components; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and 2, 6-naphthalenedicarboxylic acid. The branched diol is a diol having a branched alkyl group, and examples thereof include 2, 2-dimethyl-1, 3-propanediol, 2-methyl-2-ethyl-1, 3-propanediol, 2-methyl-2-butyl-1, 3-propanediol, 2-methyl-2-propyl-1, 3-propanediol, 2-methyl-2-isopropyl-1, 3-propanediol, 2-methyl-2-n-hexyl-1, 3-propanediol, 2-diethyl-1, 3-propanediol, 2-ethyl-2-n-butyl-1, 3-propanediol, 2-ethyl-2-n-hexyl-1, 3-propanediol, 2-di-n-butyl-1, 3-propanediol, 2-n-butyl-2-propyl-1, 3-propanediol, and 2, 2-di-n-hexyl-1, 3-propanediol.

The polyester resin can be said to contain the branched diol component as the above-described more preferable embodiment in a proportion of preferably 10 mol% or more, and more preferably 20 mol% or more of the total diol component. As the diol component other than the above compounds, ethylene glycol is most preferable. If the amount is small, diethylene glycol, propylene glycol, butanediol, hexanediol, 1, 4-cyclohexanediol, or the like may be used.

The dicarboxylic acid as a constituent of the polyester resin is most preferably terephthalic acid or isophthalic acid. If the amount is small, other dicarboxylic acids, particularly aromatic dicarboxylic acids such as diphenylformic acid and 2, 6-naphthalenedicarboxylic acid, may be added for copolymerization. In addition to the above dicarboxylic acids, 5-sulfoisophthalic acid is preferably copolymerized in an amount of 1to 10 mol% in order to impart water dispersibility to the copolyester resin, and examples thereof include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfonaphthalene isophthalic acid-2, 7-dicarboxylic acid, 5- (4-sulfophenoxy) isophthalic acid, and salts thereof.

The lower limit of the content of the crosslinking agent is preferably 5% by mass, more preferably 7% by mass, still more preferably 10% by mass, and most preferably 12% by mass, assuming that the total of the solid contents of the polyester resin, the polyurethane resin having a polycarbonate structure, and the crosslinking agent in the coating liquid is 100% by mass. When the content is 5% by mass or more, it is preferable that B-A is easily adjusted to 0.5at% or more in ase:Sub>A nitrogen distribution curve measured based on the element distribution in the depth direction by X-ray photoelectron spectroscopy. The upper limit of the content of the crosslinking agent is preferably 50% by mass, more preferably 40% by mass, still more preferably 35% by mass, and most preferably 30% by mass. When the content is 50% by mass or less, c-b is preferably adjusted to 300 seconds or less easily in a nitrogen distribution curve measured based on the element distribution in the depth direction by X-ray photoelectron spectroscopy.

The lower limit of the content of the polyurethane resin having a polycarbonate structure is preferably 5% by mass, assuming that the total of the solid contents of the polyester resin, the polyurethane resin having a polycarbonate structure, and the crosslinking agent in the coating liquid is 100% by mass. When the amount is 5% by mass or more, the ratio X of the OCOO bonds on the surface of the coating layer can be easily adjusted to 2.0% or more, and is preferable. The upper limit of the content of the polyurethane resin having a polycarbonate structure is preferably 50% by mass, more preferably 40% by mass, still more preferably 30% by mass, and most preferably 20% by mass. When the content of the urethane resin is 50% by mass or less, the ratio X of the OCOO bond on the surface of the coating layer is preferably easily adjusted to 10.0% or less.

The lower limit of the content of the polyester resin is preferably 10% by mass, more preferably 20% by mass, still more preferably 30% by mass, particularly preferably 35% by mass, and most preferably 40% by mass, assuming that the total of the solid contents of the polyester resin, the polyurethane resin, and the crosslinking agent in the coating liquid is 100% by mass. When the content of the polyester resin is 10% by mass or more, the coating layer preferably has good adhesion to the polyester film substrate. The upper limit of the content of the polyester resin is preferably 70% by mass, more preferably 67% by mass, still more preferably 65% by mass, particularly preferably 62% by mass, and most preferably 60% by mass. When the content of the polyester resin is 70% by mass or less, the wet heat resistance of a printed matter after UV ink processing is good and preferable.

(additives)

In the coating layer of the present invention, known additives such as a surfactant, an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, a dye, organic or inorganic particles, an antistatic agent, a nucleating agent, and the like may be added to the coating layer within a range not to impair the effects of the present invention.

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

The average particle diameter (the same applies hereinafter) of the particles in the coating layer is preferably 0.04 to 2.0 μm, and more preferably 0.1to 1.0 μm. When the average particle diameter of the inactive particles is 0.04 μm or more, unevenness is easily formed on the surface of the film, so that the workability such as the sliding property and the windability of the film is improved, and the workability at the time of bonding is good. On the other hand, when the average particle diameter of the inactive particles is 2.0 μm or less, the particles are less likely to fall off. The particle concentration in the coating layer is preferably 1to 20 mass% in the solid content.

The average particle diameter of the particles can be measured, for example, as follows: the particles on the cross section of the easy-adhesion polyester film were observed by a scanning electron microscope, and 30 particles were observed, and the average value thereof was defined as the average particle diameter.

The shape of the particles is not particularly limited as long as the object of the present invention is satisfied, and spherical particles and irregularly shaped non-spherical particles can be used. The particle size of the irregularly shaped particles can be calculated as the circle-equivalent diameter. The circle equivalent diameter is a value obtained by dividing the area of the observed particle by pi and calculating the square root to be 2 times.

(production of easily bondable polyester film)

The method for producing the easy-adhesion polyester film of the present invention is described by taking an example in which a polyethylene terephthalate (hereinafter, may be abbreviated as PET) film substrate is used, but it is needless to say that the method is not limited thereto.

After sufficiently vacuum-drying the PET resin, the PET resin was supplied to an extruder, and a molten PET resin at about 280 ℃ was melt-extruded from a T die in a sheet form to a rotating cooling roll, and cooled and solidified by an electrostatic application method to obtain an unstretched PET sheet. The non-stretched PET sheet may be a single layer or a multilayer structure formed by coextrusion.

The obtained unstretched PET sheet is subjected to uniaxial stretching or biaxial stretching to be crystal-oriented. For example, in the case of biaxial stretching, the film is stretched 2.5 to 5.0 times in the longitudinal direction by a roll heated to 80 to 120 ℃ to obtain a uniaxially stretched PET film, and then the film is held at its end by a jig, introduced into a hot air zone heated to 80 to 180 ℃ and stretched 2.5 to 5.0 times in the width direction. In the case of uniaxial stretching, the stretching is carried out in a tenter to 2.5 to 5.0 times. After the stretching, the resultant is introduced into a heat treatment region and heat treated to complete the crystal orientation.

The lower limit of the temperature of the heat treatment zone is preferably 170 c, more preferably 180 c. When the temperature of the heat treatment zone is 170 ℃ or higher, the curing becomes sufficient, and the blocking resistance in the presence of water in a liquid becomes good, and it is preferable that the drying time is not prolonged. On the other hand, the upper limit of the temperature of the heat treatment region is preferably 230 ℃ and more preferably 200 ℃. When the temperature of the heat treatment zone is 230 ℃ or lower, there is no fear of deterioration of the physical properties of the film, and it is preferable.

The coating layer may be provided after the film is produced or during the production process. In particular, from the viewpoint of productivity, it is preferable to form a coating layer by applying a coating liquid to at least one side of an unstretched or uniaxially stretched PET film in any stage of the film production process.

Any known method can be used for applying the coating liquid to the PET film. Examples thereof include a reverse roll coating method, a gravure coating method, a kiss coating method, a die coating method, a roll brush method, a spray coating method, an air knife coating method, a wire bar coating method, a tube blade coating method, a dip coating method, a curtain coating method, and the like. These methods may be applied singly or in combination.

The thickness of the coating layer in the present invention can be suitably set in the range of 0.001 to 2.00. Mu.m, but in order to achieve both workability and adhesion, the thickness is preferably in the range of 0.01 to 1.00. Mu.m, more preferably 0.02 to 0.80. Mu.m, and still more preferably 0.05 to 0.50. Mu.m. When the thickness of the coating layer is 0.001 μm or more, the adhesiveness is good and preferable. When the thickness of the coating layer is 2.00 μm or less, blocking is less likely to occur, and it is preferable.

The upper limit of the haze of the easy-adhesion polyester film in the present invention is preferably 1.5%, more preferably 1.3%, still more preferably 1.2%, and particularly preferably 1.0%. When the haze is 1.5% or less, it is preferable from the viewpoint of transparency, and it can be suitably used for an optical film which requires transparency.

(UV curing ink)

The UV curable ink in the present invention is a generic name of inks cured by ultraviolet light. The ink is an ink containing a pigment (dye), an oligomer, a monomer, a photopolymerization initiator, an accelerator, an auxiliary agent, and the like as components. The oligomer and the monomer function as a fluid component in the main component, spread on a printing object, and then cured by radicals generated from a photopolymerization initiator by an ultraviolet lamp. The ratio of the oligomer and monomer species contained varies depending on the printing method described later. Basically, it is preferable that the solvent is not contained or even contained at most by about 10 parts by mass except for the purpose of viscosity adjustment.

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

(light-resistant UV curing ink)

The light-resistant UV curable ink in the present invention preferably contains an ultraviolet absorber. The ultraviolet absorber absorbs the irradiated ultraviolet rays to prevent deterioration of the coating film due to the ultraviolet rays. The content of the ultraviolet absorber is preferably 0.5 to 10 parts by weight, and more preferably 1to 3 parts by weight, based on the total amount of the ink. When the content of the ultraviolet absorber is less than 0.5%, the lamination strength tends to deteriorate due to deterioration of the coating film after irradiation with ultraviolet rays, and when the content is 10% by weight or more, initial adhesion to a printed matter may be suppressed by suppressing flexibility of the resin contained in the ink. The ultraviolet absorber may be used alone or in combination of 2 or more. As the ultraviolet absorber, any of a benzotriazole-based ultraviolet absorber having a benzotriazole skeleton having an ethylenically unsaturated bond, a benzophenone-based ultraviolet absorber having a benzophenone skeleton, a salicylic acid-based ultraviolet absorber having a salicylic acid in the skeleton, a cyanoacrylate-based ultraviolet absorber having a cyanoacrylate skeleton, a hindered phenol-based ultraviolet absorber having a hindered phenol skeleton, and a triazine-based ultraviolet absorber having a triazine skeleton may be used, or 2 or more kinds may be used in combination.

For example, a product packaged with a laminate may be stored under light irradiation for a long period of time. The decrease in the aggregating force or the decrease in the adhesive force of the printing ink coating film due to the influence of the radicals generated under such conditions leads to a decrease in the lamination strength, and when a laminate stored for a long period under light irradiation is unsealed, there is a concern that the problem of delamination of the layers may occur, and therefore, light resistance is required.

(UV curing type screen ink)

The UV-curable screen ink in the present invention preferably contains acrylic resin acrylate. The acrylic resin acrylate may have an acid value. By having an acid value, dispersibility with the colorant can be promoted. As a result, clogging at the time of screen printing can be prevented, and a printed layer having high appearance can be provided. From the viewpoint of improving the pigment dispersibility, the acid value of the acrylic resin acrylate is preferably 10mgKOH/g or more.

As a method of imparting an acid value to the acrylic resin acrylate, a method of copolymerizing a monomer containing a monomer having an acid value as a monomer can be exemplified. Examples of the monomer having an acid value include (meth) acrylic acid, maleic anhydride, 2- (meth) acryloyloxyethyl-succinic acid, 2- (meth) acryloyloxyethyl-hexahydrophthalic acid, 2- (meth) acryloyloxyethyl-phthalic acid, and 2- (meth) acryloyloxyethyl acid phosphate, and among them, (meth) acrylic acid is preferably used.

(Screen printing)

Screen printing is a kind of stencil printing in which ink is applied to a material to be printed by placing ink on a plate between holes (holes) and pushing the ink out to the opposite side using a doctor blade called a squeegee. This is a system in which the degree of freedom of the ink and the object to be printed that can be printed is higher than that of other printing systems. Further, it is also a feature of screen printing that the ink thickness (print film thickness) at the time of printing can be adjusted to be larger than in other printing methods.

(solvent-based ink)

The solvent-based ink in the present invention is a generic term of ink that is cured by evaporation drying. The ink is an ink containing a pigment (dye), a resin component, a diluting solvent, an auxiliary agent, and the like as a composition. The ink is an ink in which a solvent is rapidly evaporated after printing to leave a resin component and a pigment component fixed on a surface to be printed, and is suitable for high-speed and large-volume printing because the drying speed is extremely high.

Oxidative polymerization type ink

(oxidative polymerization type ink)

The oxidative polymerization type ink in the present invention is an ink having as a main component a drying oil which is polymerized/curable by oxygen in the air, and further contains a pigment (dye), a polymerization accelerator, an auxiliary agent, and the like. The drying oil functions as a fluid component, and the viscosity is adjusted according to the printing method. Recently, there are also composite types including both an ultraviolet curing component and a drying oil, and the solvents described above mainly represent organic solvents, and include hydrocarbons such as hexane and heptane, esters such as methyl acetate and ethyl acetate, ketones such as acetone and MEK, and these solvents alone or in a mixture with alcohols. Monomers, oligomers, and oils having polymerization/curing properties are not contained in the organic solvent. Examples of printing methods using these include flexographic printing, screen printing, and offset printing. The viscosity of the ink can be set higher the latter.

(thermal transfer ink)

The thermal transfer ink in the present invention is a thermal melting pigment ink, and is used in a thermal transfer method in which ink applied to an ink ribbon is dissolved by heat and transferred to paper for printing. The ink contains various additives such as a colorant such as a pigment and a dye, a binder such as a wax and a thermoplastic resin, and a softening agent and a dispersing agent. As the ink used for the thermal transfer method, a resin type or a wax type can be used. Among them, the resin type is excellent in weather resistance and therefore can be suitably used. For use, the printer can be used for monochromatic document output of a word processor, a typewriter and a bar code label printer. In addition, some of the color tapes are used for color printers and image printers.

(LBP toner)

The toner in the present invention is a powder for coloring used in a laser printer or a copier, and is a mixture of particles (polymer resin) having chargeability, wax, pigment, and the like. In the case of color printing, 4 colors of cyan/magenta/yellow/black are used. LBP refers to a sheet printer in which a roller is charged with laser light and toner is electrostatically attached.

Examples

Next, the present invention will be described in detail with reference to examples and experimental examples, but the present invention is not limited to the following examples.

[ production of polyester resin pellets P-1 ]

High-purity terephthalic acid and 2-fold molar amount of ethylene glycol were charged into a 2-liter stainless steel autoclave equipped with a stirrer, and esterification reaction was carried out by adding 0.3 mol% of triethylamine to the acid component and distilling off water to the outside of the system at 250 ℃ under a pressure of 0.25MPa, whereby a mixture of bis (2-hydroxyethyl) terephthalate and an oligomer (hereinafter referred to as BHET mixture) having an esterification rate of about 95% was obtained. Subsequently, while stirring the BHET mixture, an ethylene glycol solution of antimony trioxide as a polymerization catalyst was added so that the amount of antimony atoms was 0.04 mol% based on the acid component in the polyester, and the mixture was stirred at 250 ℃ for 10 minutes under normal pressure in a nitrogen atmosphere. Then, it took 60 minutes to heat up to 280 ℃ and gradually decrease the pressure of the reaction system to 13.3Pa (0.1 Torr), and further, polycondensation reaction was carried out at 280 ℃ and 13.3 Pa. After releasing the pressure, the resin was quenched by ejecting the resin in a strand form into cold water, and then kept in the cold water for 20 seconds, and then cut into pellets having a cylinder shape of about 3mm in length and about 2mm in diameter.

The polyester pellets obtained by melt polymerization were dried under reduced pressure (13.3 Pa or less, 80 ℃ C., 12 hours), and then subjected to crystallization treatment (13.3 Pa or less, 130 ℃ C., 3 hours, further 13.3Pa or less, 160 ℃ C., 3 hours). The polyester pellets after cooling were subjected to solid-phase polymerization while keeping the system at 215 ℃ or lower at 13.3Pa or lower in a solid-phase polymerization reactor to obtain polyester pellets having an intrinsic viscosity of 0.62 dl/g.

[ production of polyester pellets P-2 ]

(preparation of aluminum Compound)

A20 g/l aqueous solution of basic aluminum acetate (aluminum hydroxydiacetate; manufactured by Aldrich) prepared by heating at 80 ℃ for 2 hours under stirring and having confirmed a chemical shift of the peak position of the 27Al-NMR spectrum to the low magnetic field side was put into a flask together with an equal amount (volume ratio) of ethylene glycol, stirred at room temperature for 6 hours, and then water was distilled out of the system while stirring at 90 to 110 ℃ under reduced pressure (133 Pa) for several hours to prepare a 20g/l ethylene glycol solution of an aluminum compound.

(preparation of phosphorus Compound)

Irganox1222 (manufactured by Ciba Japan K.K.) as a phosphorus compound was put in a flask together with ethylene glycol, and heated at a liquid temperature of 160 ℃ for 25 hours while stirring under nitrogen substitution, to prepare 50g/l of an ethylene glycol solution of the phosphorus compound. About 60 mol% conversion to hydroxyl groups was confirmed by measurement of 31P-NMR spectrum.

(preparation of a mixture of ethylene glycol solution of aluminum Compound/ethylene glycol solution of phosphorus Compound)

Each of the ethylene glycol solutions obtained in the above aluminum compound production and phosphorus compound production was put into a flask so that the molar ratio of aluminum atoms to phosphorus atoms became 1:2 manner, the catalyst solution was prepared by mixing at room temperature and stirring for 1 day. Chemical shifts were observed in both the 27Al-NMR spectrum and the 31P-NMR spectrum of the mixed solution in any cases.

The same operation as in the production of the polyester pellet P-1 was carried out except that the above-mentioned mixture of the ethylene glycol solution of the aluminum compound/the ethylene glycol solution of the phosphorus compound was used as the polycondensation catalyst and added in such a manner that the amount of the aluminum atom and the amount of the phosphorus atom in the acid component in the polyester were 0.014 mol% and 0.028 mol%, respectively. Polyester pellets P-2 having an intrinsic viscosity of 0.65dl/g were obtained.

(polymerization of polyurethane resin A-1 having a polycarbonate Structure)

Into a 4-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen introduction tube, a silica gel drying tube and a thermometer were introduced 32 parts by mass of 1, 3-cyclohexyl diisocyanate, 7 parts by mass of dimethylolpropionic acid, 58 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 800, 3 parts by mass of neopentyl glycol and 84.00 parts by mass of acetone as a solvent, and the mixture was stirred at 75 ℃ for 3 hours under a nitrogen atmosphere to confirm that the reaction mixture had reached a predetermined amine equivalent. Next, the reaction solution was cooled to 40 ℃, and 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450g 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 ℃ for 2000min ^-1 The polyurethane prepolymer solution was added to the mixture while stirring and mixing the mixture, and the mixture was dispersed in water. Then, a part of acetone and water was removed under reduced pressure to prepare a water-dispersible polyurethane resin solution (A-1) having a solid content of 34%.

(polymerization of polyurethane resin A-2 having a polycarbonate Structure)

Into a 4-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet, a silica gel drying tube and a thermometer, 38 parts by mass of 4, 4-dicyclohexylmethane diisocyanate and 9 parts by mass of dimethylolpropionic acid were charged53 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 1000, and 84.00 parts by mass of acetone as a solvent were stirred at 75 ℃ for 3 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution reached a predetermined amine equivalent. Then, the reaction solution was cooled to 40 ℃ and 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450g 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 ℃ for 2000min ^-1 The mixture was stirred and dispersed in water by adding the polyurethane prepolymer solution. Then, a part of acetone and water was removed under reduced pressure to prepare a water-dispersible polyurethane resin solution (A-2) having a solid content of 35%.

(polymerization of polyurethane resin A-3 having a polycarbonate Structure)

In a 4-neck flask equipped with a stirrer, a serpentine condenser, a nitrogen introduction tube, a silica gel drying tube and a thermometer, 30 parts by mass of 4, 4-dicyclohexylmethane diisocyanate, 16 parts by mass of polyethylene glycol monomethyl ether having a number average molecular weight of 700, 50 parts by mass of polyhexamethylene carbonate glycol having a number average molecular weight of 1200, 4 parts by mass of neopentyl glycol and 84.00 parts by mass of acetone as a solvent were charged, and the mixture was stirred at 75 ℃ for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached a predetermined amine equivalent. Then, the reaction solution was cooled to 40 ℃ to obtain a polyurethane prepolymer solution. Next, 450g 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 ℃ for 2000min ^-1 The polyurethane prepolymer solution was added to the mixture while stirring and mixing the mixture, and the mixture was dispersed in water. Then, a water-dispersible polyurethane resin solution (a-3) having a solid content of 35% was prepared by removing a part of acetone and water under reduced pressure.

(polymerization of polyurethane resin A-4 having polycarbonate Structure)

Into a 4-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet, 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 having a number average molecular weight of 2000, and 1 part by mass of neopentyl glycol were chargedThe reaction mixture was stirred at 75 ℃ for 3 hours under a nitrogen atmosphere with 84.00 parts by mass of acetone as a solvent to confirm that the reaction mixture had reached a predetermined amine equivalent. Next, the reaction solution was cooled to 40 ℃, and 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450g 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 ℃ for 2000min ^-1 The mixture was stirred and dispersed in water by adding the polyurethane prepolymer solution. Then, a water-dispersible polyurethane resin solution (A-4) having a solid content of 34 mass% was prepared by removing a part of acetone and water under reduced pressure.

(polymerization of polyurethane resin A-5 containing no polycarbonate polyol component)

A multistage isocyanate polyaddition method using a polyether polyol, an organic polyisocyanate and diethylene glycol as a chain extender, wherein the reaction is carried out at a temperature of 70 to 120 ℃ for 2 hours. The obtained urethane prepolymer was mixed with an aqueous bisulfite solution, and reacted with stirring sufficiently for about 1 hour to terminate the urethane prepolymer. The reaction temperature is set to 60 ℃ or lower. Then, the mixture was diluted with water to prepare a heat-reactive water-dispersible polyurethane resin solution (A-5) having a solid content of 20 mass%.

(polymerization of polyurethane resin A-6 having polycarbonate Structure)

In a 4-neck flask equipped with a stirrer, a serpentine condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer, 54 parts by mass of 4, 4-dicyclohexylmethane diisocyanate, 16 parts by mass of polyethylene glycol monomethyl ether having a number average molecular weight of 700, 18 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 1200, 12 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were charged, and the mixture was stirred at 75 ℃ for 3 hours under a nitrogen atmosphere to confirm that the reaction solution had reached a predetermined amine equivalent. Next, the reaction solution was cooled to 40 ℃, and 8.77 parts by mass of triethylamine was added thereto to obtain a polyurethane prepolymer solution. Next, 450g 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 ℃ for 2000min ^-1 Stirring and mixing, adding polyurethane prepolymer solutionThe water was dispersed. Then, a water-dispersible polyurethane resin solution (a-6) having a solid content of 34 mass% was prepared by removing a part of the acetone and water under reduced pressure.

Table 2 shows 2 items described below.

Mass ratio of polycarbonate polyol component to polyisocyanate component (polycarbonate polyol component/polyisocyanate component) in the synthesis and polymerization of polyurethane resin for forming coating layer

Molecular weight of the polycarbonate polyol component

[ Table 2]

(polymerization of blocked isocyanate crosslinking agent B-1)

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

(polymerization of blocked isocyanate crosslinking agent B-2)

100 parts by mass of a polyisocyanate compound having an isocyanurate structure (manufactured by Asahi Kasei Chemicals Corporation, duRANATE TPA), 55 parts by mass of propylene glycol monomethyl ether acetate, and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) each of which was prepared from hexamethylene diisocyanate were charged into a flask equipped with a stirrer, a thermometer, and a reflux condenser, and the mixture was held at 70 ℃ for 4 hours under a nitrogen atmosphere. Then, the temperature of the reaction solution was lowered to 50 ℃, and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of the isocyanate group had disappeared, thereby obtaining oxime-blocked isocyanate crosslinking agent (B-2) having a solid content of 40% by mass. The number of functional groups of the blocked isocyanate crosslinker is 3.

(polymerization of carbodiimide B-3)

168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400) were put into a flask equipped with a stirrer, a thermometer and a reflux condenser, and stirred at 120 ℃ for 1 hour, and further 26 parts by mass of 4,4' -dicyclohexylmethane diisocyanate and 3.8 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide (2% by mass relative to the total isocyanate) as a carbodiimidization catalyst were added thereto, and further stirred under nitrogen flow at 185 ℃ for 5 hours. The infrared spectrum of the reaction solution was measured, and the wavelength of 220 to 2300cm was confirmed ^-1 The absorption of (2) disappears. The mixture was cooled to 60 ℃ and then added with 567 parts by mass of ion-exchanged water to obtain a carbodiimide aqueous resin solution (B-3) having a solid content of 40% by mass.

(polymerization of polyester resin C-1)

194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass of sodium dimethyl-5-sulfoisophthalate, 185 parts by mass of neopentyl glycol, 188 parts by mass of ethylene glycol, and 0.2 part by mass of tetra-n-butyl titanate were charged into a stainless autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, and an ester exchange reaction was carried out at a temperature of 160 ℃ to 220 ℃ over 4 hours. Subsequently, the temperature was raised to 255 ℃ and the pressure of the reaction system was gradually reduced, followed by reaction under a reduced pressure of 30Pa for 1 hour and 30 minutes to obtain a copolyester resin (C-1). The resulting copolyester resin (C-1) was pale yellow and transparent. The reduced viscosity of the copolyester resin (C-3) was measured, and found to be 0.40dl/g. The glass transition temperature based on DSC is 65 ℃.

(preparation of aqueous polyester Dispersion Cw-1)

In a reactor equipped with a stirrer, a thermometer and a reflux unit, 25 parts by mass of the polyester resin (C-1) and 10 parts by mass of ethylene glycol n-butyl ether were charged, and the mixture was heated and stirred at 110 ℃ to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water was slowly added to the polyester solution while stirring. After the addition, the mixture was cooled to room temperature while stirring the liquid, to prepare a milky white aqueous polyester dispersion (Cw-1) having a solid content of 25 mass%.

(example 1)

(1) Preparation of coating liquid

A coating solution having a solid content mass ratio of 25/26/49 of polyurethane resin solution (A-1)/crosslinking agent (B-1)/aqueous polyester dispersion (Cw-1) was prepared by mixing the following coating agent in a mixed solvent of water and isopropyl alcohol.

(2) Production of easily bondable polyester film

As a film base polymer, polyester pellets P-1 were dried at 135 ℃ under a reduced pressure of 133Pa for 6 hours. Then, the sheet was fed to an extruder, melt-extruded at about 280 ℃ into a sheet form, and rapidly cooled, closely adhered and solidified on a rotating cooling metal roll kept at a surface temperature of 20 ℃ to obtain an unstretched PET sheet.

The unstretched PET sheet was heated to 100 ℃ with a heated roll set and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll set having a peripheral speed difference to obtain a uniaxially stretched PET film.

Subsequently, the coating liquid was left to stand at room temperature for 5 hours or more, applied to one side of a PET film by a roll coating method, and then dried at 80 ℃ for 20 seconds. The coating weight after drying of the final (after biaxial stretching) was adjusted to 0.15g/m ² (thickness of the coating layer after drying 150 nm). Then, the film was stretched 4.0 times in the width direction at 120 ℃ by a tenter, and the film was held at 230 ℃ with the length in the width direction fixedThen, the film was heated for 5 seconds and further subjected to a relaxation treatment in the width direction at 100 ℃ for 3% for 10 seconds to obtain a 100 μm polyester film having easy adhesiveness.

(3) Manufacture of printed matter

( Print (1) with UV-curable ink layer: low radiation dose )

On the coating layer of the easy-adhesion polyester film, a light-resistant UV curable ink having the following composition was used, and the ink was printed by a printer (product name "RI Taster" manufactured by Ming Ltd.) "]And (6) printing. Then, 30 seconds after the start of printing, the film coated with the ink layer was irradiated with a cumulative light amount of 40mJ/cm using a high-pressure mercury lamp ² The UV curable offset printing ink is cured by the ultraviolet ray of (1), and a printed matter (1) having a light-resistant UV curable ink layer is obtained.

(light-resistant UV curable ink)

100 parts by mass of "BEST CURE (registered trademark) UV161 blue S" manufactured by T & K TOKA

Benzophenone-based ultraviolet absorber (manufactured by Chemisaw 11, chemipro Kasei Ltd.) 4 parts by mass

( Print (2) with UV-curable ink layer: screen printing )

On the coating layer of the easily adhesive polyester film, a UV curable screen printing INk (product name "TU240 FDSS 911INk" manufactured by TOYOINK CORPORATION) was used "]Printing was performed using a Tetoron Screen (# 250 mesh), and then the ink layer-coated film was irradiated with 500mJ/cm using a high-pressure mercury lamp ² The UV curable screen printing ink is cured by the ultraviolet ray of (2) to obtain a printed matter (2) having a UV curable screen printing ink layer.

( Printed matter (3) having UV-curable ink layer: high speed printing )

On the coating layer of the easy-adhesion polyester film, printing was performed by a center impression (central impression) type printer using a light-resistant UV curable ink having the following composition. With a pore volume of 11cm ³ The anilox roller measures the ink, transfers it to the full-face plate, and then transfers it to the film. The ink transferred onto the film was cured by a 160W/cm metal halide lamp UV lamp to obtain a printed matter (3) having a light-resistant UV-curable ink layer. From ink transfer to the film to UThe time until V light irradiation was performed at 0.94 seconds.

(light-resistant UV curable ink)

100 parts by mass of "BEST CURE (registered trademark) UV161 blue S" manufactured by T & K TOKA

Benzophenone-based ultraviolet absorber (manufactured by Chemisaw 11, chemipro Kasei Ltd.) 4 parts by mass

(printed matter having solvent-based ink layer)

On the coating layer of the easy-adhesion polyester film, printing was performed using solvent-based ink [ Jujo ink co., ltd. System, 900 series Tetron ink ] using a Tetron Screen (# 250 mesh), and then the film coated with the ink layer was left to dry for 24 hours to obtain a printed matter having a solvent-based ink layer.

(printed matter having oxidative polymerization type ink layer)

Oxidative polymerization type ink (black, manufactured by Jujo chemical co., ltd., manufactured by Teton) was mixed with a dilution solvent (Jujo chemical co., ltd., manufactured by Teton) in an amount of ink: dilution solvent =4:1 (volume ratio), and printing on the surface of the film (the surface of the cover layer in the case where the cover layer is provided) by a Tetoron Screen (# 250 mesh), followed by drying for 24 hours after leaving to obtain a printed matter having an oxidative polymerization type ink layer.

(printed matter having thermal transfer ink layer)

A bar code pattern arbitrarily prepared was printed on the coating layer of the easy-adhesion polyester film by mounting on a BLP-323 made by Bon Electric co.

(printed matter having LBP toner layer)

An arbitrarily prepared pattern was printed on the coating layer of the easy-adhesion polyester film using ApeosPort-V C3376, FUJI XEROX, to obtain a printed matter having an LBP toner layer.

The evaluation results are shown in table 5.

(example 2)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the urethane resin was changed to (a-2).

(example 3)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the urethane resin was changed to (a-3).

(example 4)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the crosslinking agent was changed to (B-2).

(example 5)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropyl alcohol so that the solid content mass ratio of the polyurethane resin solution (a-1)/the crosslinking agent (B-1)/the aqueous polyester dispersion (Cw-1) was changed to 22/10/68.

(example 6)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 5 except that the urethane resin was changed to (a-2).

As shown in Table 5, in examples 1to 6, "B-A", "B" and "c-B" each satisfy the following formulase:Sub>A range, and the haze and the blocking resistance can be satisfied.

(i)0.5≤B-A(at％)≤3.0

(ii) B (second) is more than or equal to 30 and less than or equal to 180

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

Further, "X" satisfies the following formula and can satisfy adhesion to each ink layer. Further, it was found that the UV curable ink was excellent in adhesion to the UV curable ink during low-dose processing and high-speed printing.

(iv)2.0≤X(％)≤10.0

(example 7)

An easily adhesive polyester film and a printed matter were obtained in the same manner as in example 1 except that the polyester pellets were changed to (P-2) as a film raw material polymer.

As shown in Table 5, in example 7, "B-A", "B" and "c-B" each satisfy the following formulase:Sub>A range, and the blocking resistance can be satisfied.

(i)0.5≤B-A(at％)≤3.0

(ii) B is more than or equal to 30 and less than or equal to 180 in second

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

Further, "X" satisfies the following formula, and can satisfy adhesion to each ink layer. Further, it is found that the UV curable ink has excellent adhesion particularly in low-dose processing and high-speed printing.

(iv)2.0≤X(％)≤10.0

Further, it was confirmed that: the haze value was small and the transparency of the film was improved as compared with examples 1to 6 using the polyester pellets P-1.

(Experimental example 1)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropyl alcohol so that the solid content ratio of the polyurethane resin solution (a-5)/the aqueous polyester dispersion (Cw-1) was changed to 29/71.

As shown in table 5, in experimental example 1, "X" was less than 2.0%, and therefore, the adhesion to each ink layer was not satisfied. In addition, since "b" exceeds 180 seconds, the blocking resistance cannot be satisfied.

(Experimental example 2)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the urethane resin was changed to (a-4).

(Experimental example 3)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the urethane resin was changed to (A-4) and the crosslinking agent was changed to (B-2).

As shown in table 5, in experimental examples 2 and 3, "B-ase:Sub>A" was less than 0.5at%, and therefore adhesion to the solvent-based ink layer was not satisfied.

(Experimental example 4)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropyl alcohol so that the solid content ratio of the urethane resin solution (a-4)/the crosslinking agent (B-1) was changed to 70/30.

As shown in table 5, in experimental example 4, "c-b" exceeded 300 seconds, and thus the haze could not be satisfied.

(Experimental example 5)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropyl alcohol so that the solid content ratio of the urethane resin solution (a-4)/the crosslinking agent (B-1) was changed to 20/80.

As shown in Table 5, in Experimental example 5, "c-b" exceeded 300 seconds, and thus the haze could not be satisfied.

(Experimental example 6)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 5 except that the polyurethane resin was changed to (A-2) and the crosslinking agent was changed to (B-3).

As shown in Table 5, in Experimental example 6, "B-A" was less than 0.5at%, and therefore the blocking resistance and the adhesion to the solvent-based ink layer could not be satisfied.

(Experimental example 7)

An easily adhesive polyester film and a printed material were obtained in the same manner as in example 5 except that the urethane resin was changed to (a-6).

As shown in table 5, in experimental example 7, since "X" was less than 2.0%, adhesion to each ink layer could not be satisfied.

The evaluation method used in the present invention will be described below.

(1) Haze degree

The haze of the obtained easy-adhesion polyester film was measured in accordance with JIS K7136: 2000 and measured by a turbidimeter (NDH 5000, manufactured by Nippon Denshoku Kogyo Co., ltd.).

(2) Blocking resistance

2 film samples were stacked so that the coating layers faced each other, and a load of 98kPa was applied to the film samples, and the film samples were closely adhered and left to stand at 50 ℃ for 24 hours. Then, the film was peeled off, and the peeled state was determined by the following criteria.

O: the coating layer is less transferred and can be peeled off lightly.

And (delta): the coating layer is maintained, but the surface layer of the coating layer is locally transferred to the opposite surface.

X: the 2 films were fixed and could not be peeled off, or even if peeled off, the film substrate was cracked.

(3) Adhesion Property

For the ink layer of the obtained printed matter, 100 grid-like cuts penetrating the ink layer and reaching the base film were cut out using a cutter guide having a gap interval of 2 mm. Then, a cellophane tape (Nichiban CO., LTD., manufactured by No. 405; 24mm width) was stuck to the cut surface of the square lattice pattern, and the cut surface was completely adhered by rubbing with an eraser. Then, the cellophane tape was peeled off 5 times perpendicularly from the ink layer surface of the easy-adhesive polyester film on which the ink layer was laminated, and the number of squares peeled off from the ink layer surface of the printed matter was visually counted to determine the adhesion between the ink layer and the film base material based on the following formula. Note that, of the squares, partially peeled ones are also counted as peeled squares. The adhesion was rated to 95 (%) or more.

Adhesion (%) = (1-number of peeled cells/100) × 100

(4) Determination of element distribution in depth direction

The element distribution in the depth direction of the coating layer was measured by X-ray photoelectron spectroscopy (ESCA). An Ar cluster beam expected to have low damage to an organic material is used as an ion source for etching. In order to perform uniform etching, the sample is rotated during etching. In order to minimize damage due to X-ray irradiation, the map collection at each etching time is performed using a snapshot mode capable of evaluation in a short time. For evaluation, the pattern collection was performed every 30 seconds up to 120 seconds of etching time, and every 60 seconds thereafter. Details of the measurement conditions are shown below. In the analysis, the background was removed by the shirley method.

Device K-Alpha + (manufactured by Thermo Fisher Scientific Co., ltd.)

Measurement conditions

Excitation of X-rays: monochromatized AlKa radiation

X-ray output: 12kV and 2.5mA

Photoelectron escape angle: 90 degree

Spot size: 200 μm phi

General potency (pass energy): 150eV (Snapshot mode)

Acceleration voltage of ion gun: 6kV

Cluster size: big (a)

Etching rate: the respective components of 10 nm/min (polystyrene conversion)

Sample rotation during etching: is provided with

( The etch rate was calculated using: mixing the molecular weight Mn:91000 (Mw/Mn = 1.05) monodisperse polystyrene was dissolved in toluene, and the solution was spin-coated onto a silicon wafer to produce a 155nm thick silicon wafer. )

Based on the data thus evaluated, a nitrogen distribution curve was plotted with the etching time from the surface of the coating layer as the horizontal axis and the ratio of the amount of nitrogen atoms to the total amount of carbon atoms, oxygen atoms, nitrogen atoms, and silicon atoms (nitrogen atom ratio) as the vertical axis. The nitrogen distribution curves of the easy-adhesion polyester film samples (examples 2 and 5, and experimental example 6) described later are shown in fig. 1,3, and 4, respectively. The method of determining the characteristic value of the present invention will be described with reference to fig. 2 based on the nitrogen distribution curve of example 2 shown in fig. 1. As shown in FIG. 2, the nitrogen atom ratio on the surface of the coating layer opposite to the polyester film substrate was determined by calculating B-A (at%), c-B (second) by reading A (at%), B (second) as the etching time when the nitrogen atom ratio was at ase:Sub>A maximum, B (at%), and c (second) as the etching time when the nitrogen atom ratio became 1/2B (at%) after B (second). The nitrogen atom ratio of the surface of the coating layer on the opposite side of the polyester film substrate is the nitrogen atom ratio at the time of etching time 0 (second) in the figure. (in addition, "s" in which the horizontal axis in FIGS. 1to 4 represents "etching time s" means "second" in units.)

(5) Determination of the OCOO bond ratio of the surface region

The ratio (X) of the OCOO bonds in the surface region was evaluated by X-ray photoelectron spectroscopy (ESCA). The device used was K-Alpha + (manufactured by Thermo Fisher Scientific Co.). Details of the measurement conditions are shown below. In the analysis, the background was removed by the shirley method. Further, X is calculated as an average value of measurement results of 3 or more sites.

Measurement conditions

Excitation of X-rays: monochromatic AlK alpha rays

X-ray output: 12kV and 6mA

Photoelectron escape angle: 90 degree

Spot size:

general energy (pass energy): 50eV of

Stride: 0.1eV

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

Fig. 5 and 6 are graphs showing the results of analysis of C1s spectra of the surface regions of the easy-adhesion polyester films of example 6 and experimental example 1, respectively. The solid gray line represents the measured data of the C1s profile. The peaks of the obtained actual measurement pattern are separated into a plurality of peaks, and the bond species corresponding to each peak are identified from the position and shape of each peak. Further, curve fitting was performed using peaks derived from the respective bond species, and the peak area was calculated. The bond types of the peaks (1) to (6) which may appear are shown in Table 3.

[ Table 3]

	Key seed
		(1) Black two-dot dotted line	A C-C bond
(2) Black dotted line	C-O bond, C-N bond
		(3) Black three dotted line	C = O bond
(4) Black dotted line	COO bond
		(5) Black dotted line	OCOO key
(6) Solid black line	Pi-pi bonds

The total of the peak areas derived from the respective bond species in the C1s spectrum region is the total of the peak areas of the peaks (1) to (6), and the peak area derived from the OCOO bond is the peak area of the peak (5). When the total of the peak areas derived from the respective bond species in the C1s spectrum region is taken as 100%, X (%) represents the ratio (%) of the area of the peak (5) in percentage.

Table 4 shows the results of peak area calculation for peaks (1) to (6) in example 6 and experimental example 1. As mentioned above, the data of percentage of peak (5) is X (%). The peak (3) and the peak (6) in example 6, and the peak (3) and the peak (5) in experimental example 1 were not observed.

[ Table 4]

	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％

(6) Method for measuring number average molecular weight of polycarbonate polyol

A peak derived from a methylene group adjacent to the OCOO bond was observed in the vicinity of 4.1ppm when the polyurethane resin having a polycarbonate structure was measured by proton nuclear magnetic resonance spectroscopy (1H-NMR). Further, a peak derived from methylene groups adjacent to urethane bonds formed when a polyisocyanate reacts with a polycarbonate polyol was observed in a magnetic field higher by about 0.2ppm than the peak. The number average molecular weight of the polycarbonate polyol was calculated based on the integrated value of these 2 types of peaks and the molecular weight of the monomer constituting the polycarbonate polyol.

The evaluation results of the examples and experimental examples are shown in table 5.

[ Table 5]

Industrial applicability

The easy-adhesion polyester film of the present invention has excellent adhesion to UV curable inks, solvent-based inks, oxidative polymerization-based inks, thermal transfer ribbons, and LBP toners, and is suitable as a base film for various printed matters having excellent adhesion to UV curable inks, particularly in low-radiation processing or high-speed printing.

Claims (2)

1. A printed matter comprising a polyester film base and, superimposed thereon, an easily adhesive polyester film having a coating layer on at least one surface thereof, at least 1ink layer selected from the group consisting of UV-curable inks, solvent-based inks, oxidative polymerization inks, thermal transfer ribbons and LBP toners,

the coating layer is formed by curing a composition containing a polyurethane resin having a polycarbonate structure, a crosslinking agent and a polyester resin,

in a distribution curve of nitrogen element in the coating layer measured based on the element distribution in the depth direction of the X-ray photoelectron spectroscopy, when the nitrogen atom ratio of the surface of the coating layer on the opposite side of the polyester film substrate is A (at%), the maximum value of the nitrogen atom ratio is B (at%), the etching time at which the nitrogen atom ratio shows the maximum value B (at%) is B (second), and the etching time at which the nitrogen atom ratio becomes 1/2B (at%) after B (second) is C (second), the following formulas (i) to (iii) are satisfied, and in a surface analysis spectrum measured by the X-ray photoelectron spectroscopy, the following formula (iv) is satisfied when the total of the peak areas derived from the respective bonding species in the C1s spectrum region is 100 (%), and the peak area derived from the OCOO bond is X (%),

(i)0.5≤B-A(at％)≤3.0

(ii) B (second) is more than or equal to 30 and less than or equal to 180

(iii) C-b (second) is more than or equal to 30 and less than or equal to 300

(iv)2.0≤X(％)≤10.0。

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

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