Printed media and packaging

Abstract

Printed matter (101) offset-printed with an active energy ray-curable-type ink containing an active energy ray-curable resin, the printed matter comprising an ink layer (4) comprising the active energy ray-curable-type ink, a base layer (1) having an affinity for the active energy ray-curable resin, and a modification layer (3) for modifying the ink.

Description

Printed materials, printed media, and packaging

[0001] The present invention relates to a printed matter that has been offset printed with active energy ray-curable ink, a printing medium suitable for offset printing with active energy ray-curable ink, and a packaging product formed from the printed matter.

[0002] In packaging bags for packaging food and the like, printing or the like is sometimes performed on the inner or outer surface of the base material layer, which is the outermost layer, for decorative purposes. Conventionally, this type of printing has mainly been performed using a gravure method (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-9134

[0004] The packaging bag described in Patent Document 1 is manufactured from a laminate having a film substrate layer, a printing layer, and a laminate layer. The printing layer is formed by gravure printing, and the ink composition used in this process contains an organic solvent such as an ester and a polyurethane urea resin.

[0005] As described above, in conventional packaging bags, including those disclosed in Patent Document 1, organic solvents have been used in gravure printing. However, in light of recent environmental considerations, printing methods that do not use organic solvents are desired. However, when organic solvents are replaced with, for example, aqueous solvents in gravure printing, problems arise, such as reduced print quality, which restricts design, reduced physical properties of the printed layer, and reduced productivity due to longer drying times.

[0006] To solve this problem, it is conceivable to replace gravure printing with offset printing that does not use organic solvents, for example, with active energy ray-curable ink. However, conventional offset printing is a printing method that generally uses rigid paper (e.g., cardboard) as the printing substrate, and therefore is not formulated to take into account a relatively thin substrate layer, which may result in insufficient adhesion between the substrate layer and the ink used in offset printing.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a printed matter having improved adhesion between the base layer and the ink layer, a printing medium used for the printed matter, and a packaging body using the printed matter.

[0008] A characteristic configuration of the printed matter according to the present invention for solving the above-mentioned problems is that the printed matter is offset printed with an active energy ray-curable ink containing an active energy ray-curable resin, and comprises an ink layer containing the active energy ray-curable ink, a base layer having affinity with the active energy ray-curable resin, and a modifying layer that modifies the ink layer.

[0009] According to the printed matter of this configuration, the ink layer, i.e., the ink used in offset printing with active energy ray-curable ink, is modified by providing a modified layer, which, combined with the affinity of the base layer for the active energy ray-curable resin, can improve adhesion between the base layer and the ink layer.

[0010] In the printed matter according to the present invention, the modified layer preferably contains a urethane resin.

[0011] According to the printed matter having this configuration, the modified layer contains a urethane-based resin, which can further improve the adhesion between the base layer and the ink layer.

[0012] The printed matter according to the present invention preferably further comprises a sealant layer on the side of the modified layer opposite to the ink layer.

[0013] According to the printed matter of this configuration, when a sealant layer is provided on the side of the modified layer opposite the ink layer, the modified layer can also function as an adhesive layer that bonds the base layer and the sealant layer.

[0014] In the printed matter according to the present invention, the modified layer preferably contains an acrylic resin.

[0015] According to the printed matter having this configuration, since the modified layer contains an acrylic resin, the modified layer can also function as a surface protection layer that protects the surface of the ink layer.

[0016] The printed matter according to the present invention preferably further comprises a sealant layer on the opposite side of the base layer to the ink layer, with an adhesive layer interposed therebetween.

[0017] According to the printed matter having this configuration, it is possible to protect the surface of the ink layer on one side with the modified layer, while the sealant layer on the other side can be subjected to heat sealing.

[0018] The printed matter according to the present invention is preferably irradiated with active energy rays.

[0019] According to the printed matter of this configuration, by irradiating it with active energy rays, the adhesion between the base layer and the ink layer is improved, and a printed matter with improved strength and flexibility can be obtained.

[0020] A characteristic configuration of the printing medium according to the present invention for solving the above-mentioned problems is that the printing medium is suitable for offset printing using an active energy ray-curable ink containing an active energy ray-curable resin, and comprises at least a substrate layer having affinity with the active energy ray-curable resin, and the substrate layer is configured so that adhesion to the active energy ray-curable resin can be improved by irradiation with active energy rays.

[0021] According to the printing medium of this configuration, by providing a substrate layer that has affinity with at least the active energy ray-curable resin, it is possible to maintain high adhesion of the active energy ray-curable resin (which is the main component of the ink layer) to the substrate layer even after the active energy ray-curable resin is cured by irradiation with active energy rays, and it is also possible to achieve both strength and flexibility of the printing medium.

[0022] In the printing medium according to the present invention, the actinic energy rays preferably have an acceleration voltage of 120 kV or less and an exposure dose of 25 to 50 kGy.

[0023] According to the print medium of this configuration, the adhesion of the active energy ray-curable resin to the substrate layer can be further improved.

[0024] Another characteristic configuration of a printing medium according to the present invention for solving the above problems is a printing medium suitable for offset printing with an active energy ray-curable ink containing an active energy ray-curable resin, comprising a substrate layer having at least an affinity with the active energy ray-curable resin, wherein the substrate layer has an intensity ratio R of 2 to 20, expressed by the following formula (1): R = (I1 + I2) / I0 (1), where I0 is the intensity of the amorphous peak, I1 is the intensity of the first peak (110) plane, and I2 is the intensity of the second peak (200) plane, in an X-ray diffraction pattern measured by grazing incidence X-ray diffraction measurement using a zero-dimensional detector according to the 2θ method using CuKα radiation.

[0025] In the printing medium of this configuration, the substrate layer is a crystalline material irradiated with active energy rays having a specific X-ray diffraction pattern, which improves adhesion between the substrate layer and the active energy ray-curable resin (which is the main component of the ink layer).Furthermore, the strength of the substrate layer, such as its puncture resistance, can be improved, and its flexibility can also be improved.

[0026] In the printing medium according to the present invention, the base layer is preferably configured so that adhesion to the active energy ray-curable resin can be improved by irradiation with active energy rays at an acceleration voltage of 120 kV or less and an exposure dose of 25 to 50 kGy.

[0027] According to the printing medium of this configuration, the adhesion of the active energy ray-curable resin to the base layer can be further improved, and the strength of the base layer, such as bending resistance and puncture strength, can be increased, as well as flexibility can be increased.

[0028] The print medium according to the present invention preferably further comprises a modifying layer that modifies the active energy ray-curable resin.

[0029] According to the printing medium of this configuration, by further providing a modified layer, when the printing medium is subjected to offset printing with active energy ray-curable ink, the ink layer, i.e., the ink used in the offset printing with active energy ray-curable ink, is modified, and this, combined with the fact that the base layer has affinity for the active energy ray-curable resin, can improve adhesion between the base layer and the ink layer.

[0030] In the printing medium according to the present invention, the modified layer preferably contains a urethane resin or an acrylic resin.

[0031] According to the print medium of this configuration, the adhesion between the base layer and the ink layer can be further improved, and the surface of the ink layer can be protected.

[0032] Another characteristic feature of the packaging body according to the present invention for solving the above problem resides in that it is formed from the printed matter or the printing medium.

[0033] According to the packaging body of this configuration, since it is formed from the above-mentioned printed matter or the above-mentioned printing medium, the adhesion between the base material layer and the active energy ray-curable resin is enhanced, and peeling or falling off of the active energy ray-curable resin is suppressed.

[0034] FIG. 1 is a cross-sectional view schematically showing the layer structure of a printed matter according to a first embodiment of the present invention. FIG. 2 is a schematic view illustrating an example of a printing method used in the present invention. FIG. 3 is a cross-sectional view schematically showing the layer structure of a printed matter according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing the layer structure of a printed matter according to a third embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing the layer structure of a printed matter according to a fourth embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing the layer structure of a printed matter according to a fifth embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing the layer structure of a printed matter according to a sixth embodiment of the present invention. FIG. 8 is a cross-sectional view schematically showing the layer structure of a printed matter according to a seventh embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing the layer structure of a printed matter according to an eighth embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing the layer structure of a printed matter according to a ninth embodiment of the present invention. FIG. 11 is a cross-sectional view schematically showing the layer structure of a printed matter according to a tenth embodiment of the present invention. FIG. 12 is a cross-sectional view schematically showing the layer structure of a printed matter according to an eleventh embodiment of the present invention. FIG. 13 is a schematic diagram showing an example of a packaged product including a package according to the thirteenth embodiment of the present invention. FIG. 14 is a schematic diagram showing the placement of a sample for crystallinity evaluation. FIG. 15 is a graph showing the relationship between EB irradiation energy and puncture strength. FIG. 16 is a graph showing the incidence angle dependence of the X-ray penetration depth from the PE surface. FIG. 17 is an X-ray diffraction profile of HDPE measured under specified conditions. FIG. 18 is an X-ray diffraction profile of HDPE and LLDPE measured under specified conditions. FIG. 19 is a graph showing the relationship between EB irradiation energy and peak intensity in the X-ray diffraction profile. FIG. 20 is a graph showing the relationship between EB irradiation energy and peak intensity in the X-ray diffraction profile. FIG. 21 is a table summarizing the relationship between EB irradiation energy and the X-ray diffraction profile. FIG. 22 is a schematic diagram showing the crystal system of polyethylene and the crystal planes and unit cell observed in X-ray diffraction measurement. FIG. 23 is a graph showing the relationship between EB irradiation energy and peak intensity of HDPE in the X-ray diffraction profile. Fig. 24 is a graph showing the relationship between EB irradiation energy and the peak intensity of HDPE in the X-ray diffraction profile. Fig. 25 is a graph showing the relationship between EB irradiation energy and the peak intensity of LLDPE in the X-ray diffraction profile.FIG. 26 is a graph showing the relationship between EB irradiation energy and the peak intensity of LLDPE in the X-ray diffraction profile. FIG. 27 is a table summarizing the trend in crystallinity depending on the EB irradiation energy. FIG. 28 is a schematic diagram showing the crosslinking mechanism of polyethylene using an electron beam. FIG. 29 is a photograph showing the film shape after gel fraction measurement. FIG. 30 is a photograph showing the film shape after gel fraction measurement. FIG. 31 is a graph showing the relationship between EB irradiation dose and gel fraction. FIG. 32 is a graph showing dissolution contrast. FIG. 33 is a schematic illustration showing EB single-side irradiation and double-side irradiation. FIG. 34 is a graph showing the relationship between EB irradiation dose and gel fraction for LLDPE with single-side / double-side irradiation. FIG. 35 is a graph showing the dissolution contrast for LLDPE with single-side / double-side irradiation. FIG. 36 is a graph showing the dissolution contrast for HDPE with single-side / double-side irradiation. FIG. 37 is a table summarizing the gel fraction study. Figure 38 is a graph showing the DSC / DDSC curves of LLDPE. Figure 39 is a graph showing the DSC curves of LLDPE. Figure 40 is a graph showing the relationship between EB irradiation dose and the melting point and melting enthalpy of LLDPE. Figure 41 is a graph showing the DSC curves of HDPE. Figure 42 is a graph showing the relationship between EB irradiation dose and the melting point and melting enthalpy of HDPE. Figure 43 is a graph showing the relationship between EB irradiation dose and the crystallinity of PE.

[0035] Hereinafter, embodiments of the printed matter and print medium according to the present invention will be described. However, the present invention is not intended to be limited to the embodiments, examples, and drawings described below. Note that the layer configurations shown in the drawings do not strictly represent the actual structure, shape, dimensions, thickness ratios, and size relationships of each layer.

[0036] [Printed Matter] When gravure printing is replaced by offset printing, the adhesion between the ink and the substrate layer, which is the printing medium, tends to decrease. For example, if an active energy ray-curable resin is used as the curable resin contained in the ink, and the ink is offset-printed onto the substrate layer and then irradiated with active energy rays, the ink layer becomes relatively hard, and the adhesion between the ink layer and the substrate layer decreases compared to gravure printing. When the adhesion between the ink layer and the substrate layer decreases, the occurrence of defective products increases and the yield in the manufacturing process of printed matter decreases. Furthermore, during transportation of printed matter, the ink layer may peel off due to impact or the like. Peeling of the ink layer is particularly likely to occur when the substrate layer is flexible.

[0037] One possible method for solving these problems is to increase the concentration of the active energy ray-curable resin in the ink to improve the adhesion of the ink. However, increasing the concentration of the active energy ray-curable resin in the ink increases the viscosity of the ink, which can reduce the ink's fluidity, dispersibility, leveling, and other properties, potentially resulting in a decrease in printing accuracy (reproducibility). Poor print reproducibility leads to poor visibility, which is particularly noticeable in complex patterns, characters with many strokes, and the like. As such, there is a trade-off between adhesion and print reproducibility, and it is difficult to improve adhesion while suppressing a decrease in print reproducibility simply by improving the ink components.

[0038] Based on this knowledge, the inventors conducted extensive research and found that by providing a modified layer that modifies the ink constituting the ink layer on top of the ink layer that has been cured on a substrate layer, it is possible to improve adhesion while suppressing a decrease in printing reproducibility, without relying on the concentration of the active energy ray-curable resin contained in the ink.

[0039] The mechanism by which the present invention improves ink adhesion is not clear, but is presumed to be as follows. In offset printing, the surface of the ink layer is not necessarily smooth due to factors such as the printing method and the leveling properties of the ink. Therefore, when the ink particles harden, minute gaps are formed between the ink particles in the ink layer. In this state, if a liquid ink modifier is applied to the ink layer after or before the ink layer has hardened, the ink modifier penetrates between the ink particles, and some of the ink modifier reaches the substrate layer. Then, in the process of the ink modifier hardening to form a modified layer, the ink modifier not only improves the adhesion between the ink particles but also improves the adhesion between the ink particles and the substrate layer, thereby improving the durability of the ink layer.

[0040] In offset printing, the ink peels off during transfer from the printing plate to the blanket, causing stringiness. When the ink becomes stringy, tiny bubbles can form in the ink. These tiny bubbles can reduce the adhesion of the ink layer. In particular, when the printed material is used in a retort pouch, the tiny bubbles in the ink expand during heating, significantly reducing the adhesion of the ink layer. However, it has been discovered that when an ink modifier penetrates these bubbles, the adhesion between the ink layer and the substrate layer is unexpectedly improved.

[0041] This unique phenomenon is unique to offset printing, regardless of whether the printing method is water-based or waterless. In particular, in the water-based method, printing is performed with some of the dampening water contained in the ink. When the dampening water evaporates due to irradiation with active energy rays, tiny voids (micropores) are formed in the ink. At this time, the ink modifier penetrates into the micropores in the ink by capillary action. This is thought to increase the adhesion between ink particles, which in turn increases the adhesion between the ink layer and the substrate layer.

[0042] Based on the above findings, the inventors have created a printed matter that improves the adhesion between the substrate layer and the ink layer, as well as the strength and flexibility. First to twelfth embodiments of the printed matter of the present invention will be described. The printed matter of the present invention is obtained by irradiating with active energy rays, but as mentioned above, the mechanism by which irradiation with active energy rays improves the adhesion, strength, and flexibility of the ink to the substrate layer has not been fully elucidated. Therefore, it may be considered impractical to completely specify the structure of the printed matter of the present invention as a product.

[0043] First Embodiment FIG. 1 is a cross-sectional view schematically showing the layer structure of a printed matter according to a first embodiment of the present invention.

[0044] 1 is a laminate formed by reverse offset printing. The printed matter 101 comprises, from the top (surface side), a substrate layer 1 having affinity for an active energy ray-curable resin, an ink layer 4 containing the active energy ray-curable resin, and a modifying layer 3 that modifies the ink layer 4.

[0045] Active energy rays are energy rays that can generate radical active species, and examples thereof include electromagnetic waves such as X-rays and gamma rays, particle beams such as electron beams (EB), proton beams, and alpha rays, and non-ionizing radiation such as microwaves and ultraviolet rays. Of these, electron beams (EB) have higher activation energy (energy that generates radical active species) than ultraviolet rays (UV), yet are less absorbed by the pigment contained in the ink, making them preferred for offset printing using active energy ray-curable inks. Generally, a polymerization initiator is required when curing a resin (monomer) by irradiating it with ultraviolet rays (UV). However, when a polymerization initiator is incorporated, there is a risk that the polymerization initiator not used in the curing reaction will remain in the cured product. Furthermore, even if a polymerization initiator is incorporated, the resin may not be sufficiently cured, and unreacted residual monomers may remain. Considering these factors, it is preferable that the active energy rays do not include ultraviolet rays (other than ultraviolet rays). Furthermore, the active energy rays are preferably active energy rays having higher activity energy than ultraviolet rays, since they can eliminate the need for a polymerization initiator.

[0046] <Ink Layer> The ink layer (printed layer) 4 contains an active energy ray-curable ink (hereinafter also referred to as "ink") that contains an active energy ray-curable resin. The active energy ray-curable resin is the main component of the ink layer (printed layer) 4. Here, "main component" means that it is contained in an amount of 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. The active energy ray-curable resin has a property of crosslinking (curing) between molecules of the active energy ray-curable resin (crosslinkability) by irradiating it with active energy rays, and the active species form new bonds with each other, thereby forming chemical bonds (curing) between the active energy ray-curable resin and other resins, etc. (curability).

[0047] As described above, the active energy ray-curable resin is preferably a resin that is cured by active energy rays that do not contain ultraviolet rays, and more preferably a resin that is cured by active energy rays that are stronger than ultraviolet rays. Selecting such a resin as the active energy ray-curable resin eliminates the need for a polymerization initiator in the reaction of the active energy ray-curable resin, and can reduce the amount of polymerization initiator and residual monomer remaining after curing, which is advantageous from a hygienic standpoint. In addition, if ultraviolet rays are used when curing a resin by irradiation with active energy rays, the pot life (the time until the active energy ray-curable resin cures during storage (i.e., the time it remains uncured)) is shortened, and the active energy ray-curable resin hardens over time, which may cause changes in the concentration and viscosity of the active energy ray-curable resin. Furthermore, because ultraviolet rays have low transmittance through the active energy ray-curable resin, curing progresses on the surface (irradiated surface) irradiated with ultraviolet rays in the thickness direction, while curing slows down with increasing distance from the irradiated surface, resulting in a curing gradient and making it difficult to uniformly cure the active energy ray-curable resin. However, by using active energy rays that do not contain ultraviolet rays or active energy rays with higher activity than ultraviolet rays (e.g., electron beams) as described above, the active energy ray-curable resin can be instantaneously cured (faster than when ultraviolet rays are used) without the need for a polymerization initiator. This results in a much longer pot life, and the active energy rays can reach deeper into the active energy ray-curable resin than ultraviolet rays. As a result, even when the active energy ray-curable resin is relatively thick, it can be cured more uniformly (with a smaller gradient) than when ultraviolet rays are used. Furthermore, because the active energy rays can reach the entire resin in the thickness direction, poor drying can be reduced even when the active energy ray-curable resin is relatively thick.

[0048] The ink, which is a raw material for the ink layer 4, contains the above-mentioned active energy ray-curable resin that is cured by irradiation with active energy rays, and may further contain a pigment. When the active energy ray-curable resin cures by irradiation with active energy rays, internal stress is generated due to cure shrinkage, which can be a factor in reducing adhesion between the ink layer 4 and the substrate layer 1. However, in this embodiment, the modified layer 3 is provided, so that the modified layer 3 acts as a buffer layer to suppress reduction in adhesion between the ink layer 4 and the substrate layer 1. Furthermore, the modified layer 3 modifies the ink contained in the ink layer 4, thereby improving adhesion between the ink layer 4 and the substrate layer 1.

[0049] The active energy ray-curable resin, which is one of the raw materials of the ink layer 4, may be a resin composition having (a) a resin having a hydrophilic group and an ethylenically unsaturated group (referred to as "resin (a)"), (b) a polyfunctional (meth)acrylate having a hydrophilic group (referred to as "polyfunctional (meth)acrylate (b)"), and (c) a bifunctional (meth)acrylate having hydrophobic properties (referred to as "bifunctional (meth)acrylate (c)". Note that "(meth)acrylate" means "acrylate and / or methacrylate".

[0050] (Resin (a)) The resin (a) has a hydrophilic group. Examples of the hydrophilic group include a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, and a phosphate group. Among these, a carboxy group and a hydroxy group are preferred because they provide good dispersibility of the pigment in the ink.

[0051] Resin (a) has an ethylenically unsaturated group. The iodine value of the ethylenically unsaturated group is preferably 0.5 mol / kg or more, more preferably 1.0 mol / kg or more, and even more preferably 1.5 mol / kg or more. By setting the iodine value of the ethylenically unsaturated group to the above-mentioned lower limit or more, good curing sensitivity by irradiation with active energy rays can be obtained. The iodine value of the ethylenically unsaturated group is preferably 3.0 mol / kg or less, more preferably 2.5 mol / kg or less, and even more preferably 2.2 mol / kg or less. By setting the iodine value of the ethylenically unsaturated group to the above-mentioned upper limit or less, the storage stability of the ink can be improved. The iodine value is measured in accordance with the method described in Section 6.0 of the test method of JIS K 0070:1992.

[0052] The resin (a) having a hydrophilic group and an ethylenically unsaturated group can be obtained, for example, by the following production method. That is, the resin (a) having a hydrophilic group and an ethylenically unsaturated group can be obtained by addition reaction of an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride, allyl chloride, or the like, with an active hydrogen-containing group in the resin having a hydrophilic group, such as a mercapto group, an amino group, a hydroxyl group (a hydroxy group), or a carboxyl group. However, the production method of the resin (a) is not limited to this.

[0053] Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl crotonate, and glycidyl isocrotonate.

[0054] Examples of the ethylenically unsaturated compound having an isocyanate group include acryloyl isocyanate, methacryloyl isocyanate, acryloylethyl isocyanate, and methacryloylethyl isocyanate.

[0055] The acid value of resin (a) is preferably 30 mgKOH / g or more, more preferably 60 mgKOH / g or more, and even more preferably 75 mgKOH / g or more. By setting the acid value to the above lower limit or higher, the pigment dispersibility of the ink is improved. The acid value of resin (a) is preferably 250 mgKOH / g or less, more preferably 200 mgKOH / g or less, and even more preferably 150 mgKOH / g or less. By setting the acid value to the above upper limit or lower, the ink fluidity is maintained at an appropriate level. The acid value of resin (a) is measured in accordance with the neutralization titration method in Section 3.1 of the test method of JIS K 0070:1992.

[0056] The hydroxyl value of resin (a) is preferably 30 mgKOH / g or more, more preferably 75 mgKOH / g or more, and even more preferably 100 mgKOH / g or more. By setting the hydroxyl value of resin (a) to the above lower limit or more, the pigment dispersibility of the ink is improved. The hydroxyl value of resin (a) is preferably 350 mgKOH / g or less, more preferably 275 mgKOH / g or less, and even more preferably 250 mgKOH / g or less. By setting the hydroxyl value of resin (a) to the above upper limit or less, the fluidity of the ink is maintained appropriately. The hydroxyl value of resin (a) is measured in accordance with the neutralization titration method in Section 7.1 of the test method of JIS K 0070:1992.

[0057] The weight average molecular weight (Mw) of resin (a) is preferably 5,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. By setting the weight average molecular weight (Mw) of resin (a) to the above lower limit or more, the viscosity of the ink at high shear is increased. The weight average molecular weight (Mw) of resin (a) is preferably 100,000 or less, more preferably 75,000 or less, and even more preferably 50,000 or less. By setting the weight average molecular weight (Mw) of resin (a) to the above upper limit or less, the fluidity of the ink is increased. The weight average molecular weight (Mw) of resin (a) is measured using gel permeation chromatography (GPC) in polystyrene equivalent terms.

[0058] The content of resin (a) in the ink is preferably 3 to 50% by mass, more preferably 4 to 35% by mass, even more preferably 5 to 20% by mass, and particularly preferably 10 to 15% by mass. By setting the content within this range, the pigment dispersibility of the ink can be appropriate.

[0059] Examples of resin (a) include acrylic resins, styrene-acrylic resins, styrene-maleic acid resins, rosin-modified maleic acid resins, rosin-modified acrylic resins, epoxy resins, polyester resins, polyurethane resins, and phenolic resins. Among these, acrylic resins, styrene-acrylic resins, and styrene-maleic acid resins are preferred in terms of ease of monomer availability, low cost, ease of synthesis, compatibility with other components in the ink, pigment dispersibility, etc. Resin (a) may be used alone or in combination of two or more.

[0060] More preferred specific examples of the resin (a) include (meth)acrylic acid copolymers, (meth)acrylic acid-(meth)acrylic acid ester copolymers, styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymers, styrene-maleic acid copolymers, styrene-maleic acid-(meth)acrylic acid copolymers, and styrene-maleic acid-(meth)acrylic acid ester copolymers.

[0061] (Polyfunctional (meth)acrylate (b)) The hydrophilic group contained in the polyfunctional (meth)acrylate (b) stabilizes the dispersion of the pigment in the ink, and can therefore prevent the ink from excessively decreasing in viscosity even under high shear. Examples of the hydrophilic group include an ethylene oxide skeleton, a carboxy group, a hydroxy group, an amino group, and a sulfonic acid group. Of these, a hydroxy group, which has particularly high hydrophilicity, is preferred.

[0062] The polyfunctional (meth)acrylate (b) is preferably a urethane acrylate containing a urethane group. Increasing the content of the polyfunctional (meth)acrylate (b) in the ink or increasing its molecular weight increases the viscosity of the ink and reduces its flowability. Therefore, by appropriately setting the content of the urethane group in the urethane acrylate, the cohesive force of the ink is increased, thereby improving the adhesion of the ink layer 4. By appropriately setting the content of the urethane group in the urethane acrylate, peeling of the ink layer 4 is suppressed, especially during hot water treatment, and the durability of the ink layer 4 is enhanced. The urethane bond group has a relatively high rigidity structure (hard segment), which can suppress entanglement of molecular chains. As a result, an increase in the viscosity of the ink can be suppressed, and the cohesive force of the ink printed (applied) on the substrate layer 1 can be enhanced. It is presumed that this is how the adhesion between the ink layer 4 and the substrate layer 1 is improved. Furthermore, it is presumed that the polyfunctional (meth)acrylate (b) contains a urethane acrylate, which crosslinks with radical species generated from unsaturated groups in the resin (a) upon irradiation with active energy rays, and this strong covalent bond can harden the ink particles. The proportion of urethane bonds in the polyfunctional (meth)acrylate (b) is preferably set to 0.05 mass% or less in the ink. The proportion of urethane bonds is measured by nuclear magnetic resonance (NMR).

[0063] The content of the polyfunctional (meth)acrylate (b) in the ink is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. By setting the content of the polyfunctional (meth)acrylate (b) to the above-mentioned lower limit or more, the adhesion of the ink layer 4 and the fluidity of the ink are improved. The content of the polyfunctional (meth)acrylate (b) in the ink is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, and particularly preferably 50% by mass or less. By setting the content of the polyfunctional (meth)acrylate (b) to the above-mentioned upper limit or less, an increase in the viscosity of the ink due to intermolecular forces between polar groups is suppressed, and the fluidity is improved.

[0064] The hydroxyl value of the polyfunctional (meth)acrylate (b) is preferably 30 mgKOH / g or more, more preferably 75 mgKOH / g or more, and even more preferably 100 mgKOH / g or more. By setting the hydroxyl value of the polyfunctional (meth)acrylate (b) to the above-mentioned lower limit or more, the fluidity of the ink is improved. The hydroxyl value of the polyfunctional (meth)acrylate (b) is preferably 200 mgKOH / g or less, more preferably 180 mgKOH / g or less, and even more preferably 160 mgKOH / g or less. By setting the hydroxyl value of the polyfunctional (meth)acrylate (b) to the above-mentioned upper limit or less, an increase in the viscosity of the ink due to intermolecular forces between polar groups is suppressed, and the fluidity of the ink is improved.

[0065] The weight-average molecular weight (Mw) of the polyfunctional (meth)acrylate (b) is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more. By setting the weight-average molecular weight (Mw) to the above-mentioned lower limit or higher, the ink coating film becomes flexible and the adhesion of the ink layer 4 is improved. The weight-average molecular weight (Mw) of the polyfunctional (meth)acrylate (b) is preferably 1,000 or less, more preferably 700 or less, and even more preferably 500 or less. By setting the weight-average molecular weight (Mw) to the above-mentioned upper limit or lower, an increase in the viscosity of the ink is suppressed and the fluidity of the ink is improved. The weight-average molecular weight (Mw) can be measured using gel permeation chromatography (GPC) in terms of polystyrene. Furthermore, when multiple types of polyfunctional (meth)acrylate (b) are contained in the ink, the arithmetic average value of their values ​​is taken as the weight-average molecular weight (Mw) of the polyfunctional (meth)acrylate (b) in the present invention.

[0066] The polyfunctional (meth)acrylate (b) preferably has a hydroxy group. Examples of the polyfunctional (meth)acrylate (b) having a hydroxy group include poly(meth)acrylates of polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, diglycerin, ditrimethylolpropane, isocyanuric acid, and dipentaerythritol, and alkylene oxide adducts thereof. Specific examples include trimethylolpropane di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, diglycerin di(meth)acrylate, diglycerin tri(meth)acrylate, ditrimethylolpropane di(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc. Further examples include ethylene oxide adducts, propylene oxide adducts, butylene oxide adducts, tetramethylene oxide adducts, etc. of these. Among these, pentaerythritol tri(meth)acrylate, diglycerin tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate are preferred because they can improve the pigment dispersibility and fluidity of the ink. The polyfunctional (meth)acrylate (b) may be used alone or in combination of two or more. When the polyfunctional (meth)acrylate (b) contains the same type of functional group as the resin in the modified layer 3, for example, when the polyfunctional (meth)acrylate (b) in the ink contains a urethane group and the modified layer 3 contains a urethane-based resin having a urethane group, the affinity between the two is increased, thereby further improving the adhesion of the ink layer 4 to the substrate layer 1.

[0067] (Bifunctional (meth)acrylate (c)) The bifunctional (meth)acrylate (c) has a hydroxyl value of 5 mgKOH / g or less and exhibits hydrophobicity. The bifunctional (meth)acrylate (c) preferably has a chain aliphatic skeleton having 8 to 18 carbon atoms. The chain aliphatic skeleton may be either a linear skeleton or a branched skeleton, and may have either a saturated bond or an unsaturated bond. The bifunctional (meth)acrylate (c) is moderately compatible with the resin (a) and the polyfunctional (meth)acrylate (b), thereby suppressing entanglement of molecular chains in the ink. This suppresses stringiness (stringing) when the ink is transferred, resulting in improved ink transferability. Furthermore, by including the bifunctional (meth)acrylate (c) in the ink, the surface tension of the ink is reduced and its wettability to the base layer 1 is improved, thereby improving ink transferability. Here, ink transferability refers to the property that indicates the ease with which ink transfers from a rubber (metal) roll to a rubber (metal) roll, from a rubber (metal) roll to a printing plate, from a printing plate to a blanket, and from a blanket to a base layer, and is evaluated by the ink transfer rate.

[0068] The number of carbon atoms in the bifunctional (meth)acrylate (c) is preferably 8 or more, more preferably 9 or more, and even more preferably 10 or more. By setting the number of carbon atoms in the bifunctional (meth)acrylate (c) to the above-mentioned lower limit or more, compatibility with the resin (a) and the polyfunctional (meth)acrylate (b) is maintained at a suitable level, resulting in improved ink transferability. The number of carbon atoms in the bifunctional (meth)acrylate (c) is preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less. By setting the number of carbon atoms in the bifunctional (meth)acrylate (c) to the above-mentioned upper limit or less, deterioration in compatibility with the resin (a) and the polyfunctional (meth)acrylate (b), increase in ink viscosity, and deterioration in ink transferability are suppressed.

[0069] The content of the bifunctional (meth)acrylate (c) in the ink is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more. On the other hand, the content of the bifunctional (meth)acrylate (c) in the ink is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and particularly preferably 8% by mass or less. By setting the content of the bifunctional (meth)acrylate (c) within the above range, compatibility with the resin (a) and the polyfunctional (meth)acrylate (b) is maintained at an appropriate level, resulting in improved ink transferability.

[0070] Examples of the bifunctional (meth)acrylate (c) include 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,11-undecanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, and 1,14-tetradecanediol di(meth)acrylate. Examples of suitable di(meth)acrylates include 1,15-pentadecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,17-heptadecanediol di(meth)acrylate, 1,18-octadecanediol di(meth)acrylate, 4-methyl-1,10-decanediol di(meth)acrylate, and 4-ethyl-1,10-decanediol di(meth)acrylate. Other examples include polyester di(meth)acrylates having an aliphatic skeleton having 8 to 18 carbon atoms as a repeating unit. Of these, 1,10-decanediol di(meth)acrylate is more preferred because it maintains adequate compatibility with the resin (a) and the polyfunctional (meth)acrylate (b) and can improve ink transferability. The functionality refers to the number of structures derived from (meth)acrylate. The bifunctional (meth)acrylate (c) may be used singly or in combination of two or more.

[0071] The weight average molecular weight (Mw) of the bifunctional (meth)acrylate (c) is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more. By setting the weight average molecular weight (Mw) of the bifunctional (meth)acrylate (c) to be equal to or greater than the above-mentioned lower limit, the ink coating film becomes flexible, thereby improving adhesion to the substrate layer 1. The weight average molecular weight (Mw) of the bifunctional (meth)acrylate (c) is preferably 1,000 or less, more preferably 700 or less, and even more preferably 500 or less. By setting the weight average molecular weight (Mw) of the bifunctional (meth)acrylate (c) to be equal to or less than the above-mentioned upper limit, the viscosity of the ink is maintained at a good level, resulting in good ink flowability. The weight average molecular weight (Mw) of the bifunctional (meth)acrylate (c) is measured using gel permeation chromatography (GPC) in terms of polystyrene.

[0072] The content of the bifunctional (meth)acrylate (c) relative to the total amount of the polyfunctional (meth)acrylate (b) (1.00 part by mass) is preferably 0.02 part by mass or more, more preferably 0.04 part by mass or more, and even more preferably 0.06 part by mass or more, from the viewpoint of maintaining a suitable compatibility with the polyfunctional (meth)acrylate (b) and improving ink transferability. On the other hand, the content of the bifunctional (meth)acrylate (c) is preferably 0.30 part by mass or less, more preferably 0.20 part by mass or less, even more preferably 0.15 part by mass or less, and particularly preferably 0.10 part by mass or less.

[0073] The content of the bifunctional (meth)acrylate (c) relative to the total amount of resin (a) (1.00 part by mass) is preferably 0.10 parts by mass or more, more preferably 0.15 parts by mass or more, and even more preferably 0.20 parts by mass or more, from the viewpoint of maintaining a suitable compatibility with resin (a) and improving ink transferability, while the content of the bifunctional (meth)acrylate (c) is preferably 0.60 parts by mass or less, more preferably 0.45 parts by mass or less, and even more preferably 0.30 parts by mass or less.

[0074] When the active energy ray-curable resin contained in the ink has a urethane bond, the content of the urethane bond in the ink is preferably 0.05 mass% or less. The content of the urethane bond is measured by nuclear magnetic resonance (NMR).

[0075] <Pigment> The ink preferably contains an organic pigment and / or an inorganic pigment in addition to the active energy ray-curable resin. Examples of organic pigments include phthalocyanine pigments, soluble azo pigments, insoluble azo pigments, lake pigments, quinacridone pigments, isoindoline pigments, threne pigments, and metal complex pigments. Specific examples include phthalocyanine blue, phthalocyanine green, azo red, monoazo red, monoazo yellow, disazo red, disazo yellow, quinacridone red, quinacridone magenta, and isoindoline yellow.

[0076] Examples of inorganic pigments include titanium oxide, zinc oxide, alumina white, calcium carbonate, barium sulfate, red iron oxide, cadmium red, yellow lead, zinc yellow, iron blue, ultramarine, oxide-coated glass powder, silicate minerals (mica), oxide-coated mica, oxide-coated metal particles, aluminum powder, gold powder, silver powder, copper powder, zinc powder, stainless steel powder, nickel powder, bentonite, iron oxide, carbon black, and graphite.

[0077] In the case of ink to be printed as the base color of the transparent substrate layer 1, a white pigment such as titanium dioxide, zinc oxide, or alumina white, which imparts hiding power, is preferred. The particle size of the white pigment is preferably 200 to 300 nm, from the viewpoint that the transmittance of visible light is most likely to decrease due to scattering. One type of pigment may be used alone, or two or more types may be mixed and used.

[0078] In the case of organic pigments or carbon black having a specific gravity of 2 or less, the content of the pigment in the ink is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of improving print density. Furthermore, in the case of improving ink fluidity and obtaining good transferability, the content is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. In the case of inorganic pigments having a specific gravity of more than 2, the content is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, from the viewpoint of improving ink fluidity and obtaining good transferability. Furthermore, in the case of improving ink fluidity and obtaining good transferability, the content is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0079] The ink may contain other components such as a sensitizer. The ink preferably contains a surfactant. By including a surfactant in the ink, the ink can incorporate dampening water and stabilize the emulsified state in water-based printing. The surfactant content in the ink is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of stabilizing the emulsified state. The surfactant content in the ink is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of suppressing miscibility with dampening water due to excessive absorption of dampening water by the ink during printing.

[0080] On the other hand, it is preferable that the ink is substantially free of polymerization initiators. This is because the ink can be cured by irradiation with active energy rays even without blending a polymerization initiator into the ink. Here, "substantially free of polymerization initiators" does not completely exclude the inclusion of a polymerization initiator, but means that a polymerization initiator may be contained as long as it is of a type and amount that does not adversely affect the adhesion and reproducibility of the ink layer 4 to the substrate layer 1. In other words, it is not intended that the content of polymerization initiators be strictly 0% in all cases. For example, if an extremely small amount of polymerization initiator is unintentionally contained, or if an intentionally contained extremely small amount of polymerization initiator does not exhibit any effect attributable to the polymerization initiator, it is considered to be free of polymerization initiators. Examples of cases where a trace amount of polymerization initiator is unintentionally contained include when another product containing a polymerization initiator was previously produced in the production equipment for the ink or printed matter 101, and a trace amount of polymerization initiator adhering to a container or pipe gets mixed into the ink as contamination, or when fine particles of polymerization initiator floating or volatilizing in the air in the production room adhere to the ink during production, etc. In such cases, even if a trace amount of polymerization initiator is contained, it is treated as if the ink does not substantially contain a polymerization initiator.

[0081] The viscosity of the ink, as measured using a cone-plate type rotational viscometer at 25°C and a rotation speed of 0.5 rpm, is preferably 5 to 100 Pa·s, more preferably 10 to 80 Pa·s, and even more preferably 20 to 60 Pa·s. By setting the viscosity (A) to be equal to or higher than the lower limit of each of the above ranges, the transferability of the ink becomes better. By setting the viscosity (A) to be equal to or lower than the upper limit of each of the above ranges, the fluidity of the ink becomes better, and in the case of white inks in particular, the hiding power can be improved.

[0082] The viscosity (B) at a rotation speed of 50 rpm is preferably 10 to 40 Pa·s, more preferably 15 to 35 Pa·s, and even more preferably 20 to 30 Pa·s. By setting the viscosity (B) to be equal to or higher than the lower limit of each of the above ranges, the ink transferability becomes better. By setting the viscosity (B) to be equal to or lower than the upper limit of each of the above ranges, the ink transferability can be improved.

[0083] The viscosity ratio (B) / (A), which is the ratio of the viscosity (A) to the viscosity (B), is preferably 0.25 to 0.4, more preferably 0.30 to 0.4, and even more preferably 0.35 to 0.4. By setting the viscosity ratio (B) / (A) within the above range, high-quality printed matter with smooth image lines can be obtained.

[0084] When the ink contains the above components and the physical properties of the ink are set as described above, offset printing is performed and active energy rays are irradiated (i.e., for example, by performing EB offset printing), high-precision reproducibility comparable to or exceeding that of gravure printing can be achieved.

[0085] <Substrate Layer> The substrate layer 1 is a layer that has affinity with the active energy ray-curable resin. The property of the substrate layer 1 that "has affinity with the active energy ray-curable resin" is preferably achieved by the substrate layer 1 including a resin that has affinity with the active energy ray-curable resin. "Having affinity with the active energy ray-curable resin" means that the surface of the substrate layer 1 has a property that increases adhesion to the active energy ray-curable resin in the ink layer 4 upon irradiation with active energy rays. The reason why the surface of the substrate layer 1 increases in adhesion upon irradiation with active energy rays is not clear, but it is presumed that the active energy rays generate radical active species in the molecules of the resin present on the surface of the substrate layer 1, and that these active species interact with the radical active species generated in the molecules of the active energy ray-curable resin in the ink layer 4 through some kind of interaction, such as crosslinking (covalent bonding), weaker electrostatic interaction (dipole interaction, van der Waals force, etc.), or other interaction.

[0086] In the reverse printing of this embodiment, it is desirable that the substrate layer 1 is transparent, or at least semi-transparent, so that the ink layer 4 can be seen. Therefore, a transparent thermoplastic resin is preferably used as the substrate layer 1. Specific examples include polyolefin resins such as polyethylene, polypropylene, polystyrene, and polymethylpentene; alicyclic polyolefin resins; polyamide resins such as nylon 6 and nylon 66; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polypropylene terephthalate, polybutyl succinate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and polyethylene diphenylate; polycarbonate resins, polyarylate resins, polyacetal resins, polyphenylene sulfide resins, fluorine-based resins such as trifluoroethylene resins, tetrafluoroethylene-hexafluoropropylene copolymers, and vinylidene fluoride resins; acrylic resins, methacrylic resins, polyacetal resins, polyglycolic acid resins, and polylactic acid resins. Of these, polyester resins are preferred because they can enhance strength, heat resistance, and transparency. Polyolefin resins are also preferred because they can enhance transparency, with polyethylene being more preferred. The thermoplastic resins may be used singly or in combination of two or more.

[0087] The substrate layer 1 may be a single layer or multiple layers. When the substrate layer 1 is a single layer, the substrate layer 1 may have only a resin film formed from the thermoplastic resin. When the substrate layer 1 is a multiple layer, examples of the substrate layer 1 include the following laminates. When the substrate layer 1 is a two-layer substrate, examples of the substrate layer 1 include a laminate (resin film / easy-adhesion layer) having the resin film as a base and an easy-adhesion layer described below, and a laminate (resin film / barrier layer) having the resin film layer and a barrier layer (first barrier layer) described below. When the substrate layer 1 is a three-layer substrate, examples of the substrate layer 1 include a laminate (resin film layer / easy-adhesion layer / barrier layer) having the resin film layer, easy-adhesion layer, and barrier layer in this order, and a laminate (resin film layer / barrier layer / barrier layer) having the resin film and two types of barrier layers. The barrier layer included in the substrate layer 1 may be a single layer or multiple layers. Examples of the barrier layer include a transparent vapor-deposited layer formed by vapor-depositing an inorganic compound or the like onto the resin film, a barrier coat layer of polyvinylidene chloride (PVDC) or the like, and a stretched film layer of oriented (for example, biaxially stretched) polypropylene (OPP) film or the like. Specific examples of the substrate layer 1 having such a barrier layer include a transparent vapor-deposited film formed by vapor-depositing an inorganic compound or the like onto the resin film, a PVDC-coated film formed by coating the resin film with polyvinylidene chloride (PVDC), and an OPP barrier film formed by laminating an OPP film onto the resin film.

[0088] The resin film may have a plurality of transparent vapor deposition layers, barrier coat layers, stretched film layers, etc. laminated thereon as barrier layers. For example, the substrate layer 1 may be a laminate (resin film / transparent vapor deposition layer / barrier coat layer) in which the resin film, the transparent vapor deposition layer, and the barrier coat layer are laminated in this order. For example, the substrate layer 1 may be a laminate (resin film / barrier coat layer) in which the resin film and the barrier coat layer are laminated in this order. In this case where the substrate layer 1 has the resin film layer and a single or multiple barrier layers, the ink layer 4 may be laminated on one surface of the substrate layer 1 (e.g., the surface on the resin film side), or the ink layer 4 may be laminated on the other surface (e.g., the surface on the barrier layer side). It is preferable that at least the outermost layer of the substrate layer 1 on the ink layer 4 side is a resin layer.

[0089] The thickness of the substrate layer 1 is preferably 9 to 200 μm, more preferably 9 to 100 μm, even more preferably 9 to 50 μm, and particularly preferably 9 to 35 μm. By setting the thickness of the substrate layer 1 to be equal to or greater than the lower limit of each of the above ranges, the printed matter 101 is not too thin and its strength is increased. Furthermore, by setting the thickness of the substrate layer 1 to be equal to or less than the upper limit of each of the above ranges, the processability of the printed matter 101 is improved.

[0090] The substrate layer 1 is preferably surface-treated. Specifically, for example, the substrate layer 1 is preferably a resin film formed from the above-mentioned thermoplastic resin, the surface of which is surface-treated. This enhances the adhesion between the substrate layer 1 and the layer adjacent to the substrate layer 1.

[0091] The surface treatment method is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0092] The base layer 1 may further contain additives, such as a crosslinking agent, an antioxidant, an antiblocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, and a modifying resin.

[0093] <Easy-Adhesion Layer> The substrate layer 1 preferably has an easy-adhesion layer that enhances adhesion to the ink layer 4. The easy-adhesion layer is realized by providing a layer (not shown) containing at least one compound selected from amines, amides, isocyanates, and urethanes as an easy-adhesion layer on the surface of the substrate layer 1, on the ink layer 4 side, of a resin film formed from, for example, the above-mentioned thermoplastic resin. The functional groups derived from the easy-adhesion layer are subjected to intermolecular forces such as hydrogen bonding between the resin (a) having a hydrophilic group and the polyfunctional (meth)acrylate (b) in the ink, thereby enhancing the transferability of the ink and the adhesion between the ink layer 4 and the substrate layer 1.

[0094] Examples of amines include ethylenediamine, propylenediamine, hexamethylenediamine, phenylenediamine, tolylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, ethylenediaminetetraacetic acid, N,N-dialkylaminoalkyl(meth)acrylates such as N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, and N,N-dimethylaminopropyl(meth)acrylate, 2-(methacryloyloxy)ethyltrimethylammonium chloride, 2-(methacryloyloxy)ethyltrimethylammonium chloride, and 2-(methacryloyloxy)ethyltrimethylammonium chloride. ammonium bromide, (meth)acryloyloxyalkyltrialkylammonium salts such as 2-(methacryloyloxy)ethyltrimethylammonium dimethylphosphate, (meth)acryloylaminoalkyltrialkylammonium salts such as methacryloylaminopropyltrimethylammonium chloride, methacryloylaminopropyltrimethylammonium bromide, tetraalkyl(meth)acrylates such as tetrabutylammonium (meth)acrylate, trialkylbenzylammonium (meth)acrylates such as trimethylbenzylammonium (meth)acrylate, etc. The amines may be used alone or in combination of two or more.

[0095] Examples of the amides include aliphatic amides such as ethylene bisstearic acid amide and hexamethylene bisstearic acid amide, and N,N-dialkylaminoalkyl(meth)acrylamides such as N,N-dimethylaminoethyl(meth)acrylamide, N,N-diethylaminoethyl(meth)acrylamide and N,N-dimethylaminopropyl(meth)acrylamide. One type of amide may be used alone, or two or more types may be used in combination.

[0096] Examples of isocyanates include aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane-4,4-diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, and polyisocyanates in which one or more of these compounds are pre-added with trimethylolpropane or the like. For example, containing an amine compound and an isocyanate compound in the adhesion layer also includes having an amine group and an isocyanate group in a single compound. The isocyanates may be used alone or in combination.

[0097] The urethanes contain at least a polyol and an isocyanate compound, and further contain a chain extender as needed. Urethanes can be obtained, for example, by polymerizing a polyol and an isocyanate compound using a known polymerization method. Examples of polyols include polyester polyols obtained by reacting a polycarboxylic acid (e.g., malonic acid, succinic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or an acid anhydride thereof with a polyhydric alcohol (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, neopentyl glycol, 1,6-hexanediol, etc.); polyether polyols such as polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol; polycarbonate polyols; polyolefin polyols; and acrylic polyols. The urethanes may be used alone or in combination of two or more.

[0098] The content of amines, amides, isocyanates, and urethanes contained in the easy-adhesion layer is not particularly limited, but is preferably 0.1 to 80% by mass, more preferably 1 to 50% by mass, and even more preferably 5 to 20% by mass.

[0099] The easy-adhesion layer may further contain a resin component. The resin component is not particularly limited as long as it has adhesiveness to the substrate layer 1 and / or the ink layer 4, but for example, polyester-based resins, polycarbonate-based resins, epoxy-based resins, alkyd-based resins, acrylic-based resins, urea-based resins, urethane-based resins, etc. can be suitably used. Of these, polyester-based resins, acrylic-based resins, and urethane-based resins are preferred, and polyester-based resins having a phthalic acid skeleton are more preferred.

[0100] The easy-adhesion layer may contain various additives, such as a crosslinking agent, a plasticizer, a heat stabilizer, a weather stabilizer, organic and / or inorganic fine particles, a wax, an antioxidant, a weathering agent, an antistatic agent, a pigment, etc., within a range that does not impair the properties of the film. Examples of the crosslinking agent that can be used include a melamine-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, a methylolated or alkylolated urea-based crosslinking agent, an acrylamide-based crosslinking agent, a polyamide-based crosslinking agent, an oxazoline-based crosslinking agent, a carbodiimide-based crosslinking agent, an isocyanate-based crosslinking agent, various silane coupling agents, and various titanate-based coupling agents.

[0101] The thickness of the easy-adhesion layer can be adjusted appropriately depending on the optical properties, productivity, etc., but is preferably 10 to 5,000 nm, more preferably 50 to 3,000 nm, and even more preferably 100 to 1,000 nm. By setting the thickness of the easy-adhesion layer to the above-mentioned lower limit or more, it becomes easier to apply the raw material liquid of the easy-adhesion layer uniformly and without defects onto the base layer 1, and as a result, variation in the adhesion of the easy-adhesion layer is reduced. By setting the thickness of the easy-adhesion layer to the above-mentioned upper limit or less, it is possible to prevent the easy-adhesion layer from adversely affecting the optical properties.

[0102] When the easy-adhesion layer contains the same type of resin as the resin in the modified layer 3, for example, when the modified layer 3 contains a urethane-based resin and the easy-adhesion layer contains a urethane-based resin, the affinity between the two is increased, thereby further improving the adhesion of the ink layer 4 to the base layer 1.

[0103] <Offset Printing> Fig. 2 is a schematic diagram for explaining an example of a printing method used in the present invention. As the printing method, an offset printing method is adopted.

[0104] Offset printing is a printing method that takes advantage of the water-repellent properties of oil-based offset printing ink. Unlike letterpress printing, which uses a printing plate with a textured surface, offset printing uses a printing plate 51 without a textured surface. Instead of textured surfaces, the printing plate 51 has lipophilic image areas and hydrophilic non-image areas. Offset printing may be a water-based printing method using dampening water W (water-based offset printing), or a waterless printing method using a dedicated printing plate as the printing plate 51 to print without dampening water (waterless offset printing). In water-based offset printing, the non-image areas are first moistened with dampening water W supplied to the printing plate 51 from a dampening water supply roll 52. Next, oil-based ink I is supplied to the printing plate 51 from an ink supply roll 53. At this time, ink I repels and does not adhere to the non-image areas that have been moistened with dampening water W, but adheres only to the lipophilic image areas. In this way, an image is formed in ink I on the surface of printing plate 51, the image in ink I is transferred to blanket 54, and the image is transferred (printed) from blanket 54 to base material layer 1 being transported by blanket 54 and roll 55. When ink I transferred to base material layer 1 hardens, ink layer 4 is formed, resulting in printed matter 101.

[0105] In the case of waterless offset printing, a printing plate on which non-image areas are formed using, for example, silicone resin can be used. In waterless offset printing, silicone resin, instead of dampening water, repels the ink, forming the non-image areas. Apart from this, waterless offset printing is also a common printing method with water-based offset printing using dampening water. Therefore, in this specification, the term "offset printing" is used to refer to not only water-based offset printing using dampening water, but also waterless offset printing. When waterless offset printing is used, there is no need to emulsify the dampening water and ink, which allows for a wider range of ink choices.

[0106] <Color gamut> Compared to gravure printing, offset printing tends to have lower color density and a narrower color gamut. This is presumably because the pigment content is lower than in gravure printing and the type of pigment suitable for printing is different.

[0107] <Color Density> From the viewpoint of increasing color density and widening the color gamut, for example, when using six ink colors, it is preferable to adjust the ink layer 4 with two complementary colors among the six colors to set the color gamut parameters appropriately. For example, two colors can be selected as complementary colors from among orange, green, and purple, and the density of the complementary colors can be appropriately set depending on the area where the color gamut is insufficient. Furthermore, by increasing the color density, even if the adhesion between the base layer 1 and the ink layer 4 is reduced due to the ink, the modified layer 3 prevents the reduction in adhesion as described above.

[0108] <Dot Shape> In offset printing, there is a risk of defects in the dot shape, such as dryness, occurring around the edges of dots in an image. This is thought to be caused by poor ink transfer and poor release from the blanket.

[0109] From the viewpoint of obtaining a good halftone dot shape, it is preferable to appropriately set the shape, material, etc. of the ink and process materials (rolls, blankets, etc.). In addition, in water-based offset printing, the emulsification suitability of the ink can affect the shape, so it is preferable to use an ink with excellent emulsification suitability.

[0110] <Concealing property> As described above, in offset printing, the surface of the ink layer is not necessarily smooth, and therefore, when the ink particles harden, fine gaps are formed between the ink particles in the ink layer. Therefore, when printing white ink, gaps are generated, and there is a risk of a decrease in concealing property. In order to improve concealing property, it is preferable to print the white ink twice, or to print the second time at a position shifted from the first time, and fill in the gaps generated in the first time.

[0111] It is also preferable to appropriately set the transmission density, thickness, etc. of the ink so as to enhance hiding power. For example, when printing using eight color inks, it is effective to perform offset printing for seven of the color inks and flexographic printing for the white ink. In this case, a protective layer may be formed in the flexographic printing using a varnish suitable for flexographic printing.

[0112] Offset printing is solvent-free (does not use organic solvents), so odors can be suppressed. Water-based gravure printing can also be done without using organic solvents, but it is difficult to increase the printing speed with gravure printing, resulting in reduced productivity. In contrast, offset printing can be done at a higher printing speed than gravure printing, so it is solvent-free and can increase productivity while reducing the burden on the environment.

[0113] <Irradiation with Active Energy Rays> After the ink is printed on the substrate layer 1, the active energy ray-curable resin contained in the ink is cured by irradiating it with active energy rays, and the cured resin is then fixed to obtain the ink layer 4. Electron beams (EB) are preferred as active energy rays. When curing the ink with electron beams, the irradiation dose can be appropriately set depending on the thickness of the printed ink, the pigment content in the ink, and other factors. In the case of electron beams, the irradiation dose is preferably 10 to 100 kGy, more preferably 20 to 60 kGy, and even more preferably 25 to 50 kGy. Setting the irradiation dose to above the lower limit further enhances adhesion between the substrate layer 1 and the ink layer 4. Setting the irradiation dose to below the upper limit also suppresses the decomposition reaction of the active energy ray-curable resin. Irradiation with active energy rays is preferably performed in an oxygen-depleted atmosphere (e.g., a nitrogen-filled environment). Irradiation with active energy rays in the presence of oxygen tends to make it difficult for the active energy ray-curable resin to cure. However, by irradiating the active energy ray in a deoxidized atmosphere, the active energy ray-curable resin can be easily cured.

[0114] <Modified Layer> The modified layer 3 is a layer that modifies the ink layer 4. The modified layer 3 contains an ink modifier. The substrate layer 1 and the ink layer 4 are irradiated with active energy rays, and after the ink layer 4 is cured, the modified layer 3 is provided on the ink layer 4. The modified layer 3 can also function as an adhesive. The ink modifier may be a one-component curing resin, a two-component curing resin, or a non-curing resin. It may also be a solventless resin or a solvent-based resin.

[0115] Examples of ink modifiers include polyether resins, polyester resins, silicone resins, polyamine resins, polybutadiene resins, resins obtained by adding epoxy groups to these resins, urethane resins, rubber resins, vinyl resins, epoxy resins other than those mentioned above, phenolic resins, and olefin resins. Resins containing biomass components can also be preferably used. Polyamine resins and urethane resins having gas barrier properties are more preferred as ink modifiers. One type of ink modifier may be used alone, or two or more types may be mixed together.

[0116] It is more preferable that the ink modifier contains a urethane-based resin. When the ink modifier contains a urethane-based resin, the adhesion between the substrate layer 1 and the ink layer 4 is further enhanced. The mechanism behind this is unclear, but it is presumed that, for example, urethane-based resins contain amino groups and carboxyl groups in their molecules, which makes them more likely to undergo chemical interactions (covalent bonds, electrostatic interactions, etc.) with the ink particles and the substrate layer 1. The ink modifier may be composed of a solventless adhesive composition that is also used as an adhesive composition, a cured product thereof, or a mixture thereof. The adhesive composition serving as the ink modifier may be a two-component curing type. When the ink modifier contains two components, a polyisocyanate component and a polyol component, these components may at least partially react with each other to form a cured product. The cured product may contain polyurethane. This adhesive composition can be prepared by blending a polyether polyol (manufactured by Toyo-Morton Co., Ltd., product name: EA-N373B, hereinafter referred to as "(A)") as a base agent and an aromatic polyisocyanate (manufactured by Toyo-Morton Co., Ltd., product name: EA-N373A, hereinafter referred to as "(B)") as a curing agent. The blending ratio (by mass) of the respective components can be (A):(B) = 100:50. Another example of this adhesive composition can be prepared by blending a polyester polyol (manufactured by Mitsui Chemicals, Inc., product name: Takelac A626, hereinafter referred to as "(C)") as a base agent and an aliphatic polyisocyanate (manufactured by Mitsui Chemicals, Inc., product name: Takenate A50, hereinafter referred to as "(D)") as a curing agent. The blending ratio (by mass) of the respective components can be (C):(D) = 8:1.

[0117] The thickness of the modified layer 3 can be set appropriately taking into consideration the degree to which the adhesion of the ink layer 4 to the base layer 1 can be improved, and is, for example, preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm.

[0118] The modified layer 3 can be formed by applying an ink modifier onto the ink layer 4 and drying it using a conventionally known method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, or transfer roll coating, or by applying the ink modifier onto the sealant layer 2 described below and drying it, and then laminating the sealant layer 2 on the ink layer 4.

[0119] The ratio (T1 / T2) of the thickness (T2) of the modified layer 3 to the thickness (T1) of the ink layer 4 is preferably 0.15 to 5. By setting the ratio (T1 / T2) within the above range, the adhesion between the base material layer 1 and the ink layer 4 can be further improved. In addition, heat resistance can be improved.

[0120] As described above, the provision of the modified layer 3 modifies the ink used in offset printing with active energy ray-curable ink, and this, combined with the fact that the substrate layer 1 has affinity for the active energy ray-curable resin, can improve the adhesion between the substrate layer 1 and the ink layer 4. The mechanism behind this is not clear, but as described above, it is presumed that the ink modifier penetrates into the gaps between the ink particles and into the ink particles, thereby improving the adhesion between the ink particles and between the ink particles and the substrate layer 1.

[0121] <Other Layers> The printed matter 101 may be provided with other layers such as a protective layer (impact-resistant layer), an adhesive layer, a barrier layer, a coating layer, an intermediate layer, a sealant layer, etc. Embodiments of printed matters having these layers will be described later.

[0122] The printed matter 101 may contain 90% by mass or more of the same type of resin (for example, polyethylene). In this case, the printed matter 101 may be configured as a highly recyclable mono-material. Alternatively, even in the case of olefin-based resins, from the perspective of recycling, the printed matter 101 may have a mono-olefin configuration in which, for example, the sealant layer 2 described below contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0123] As described above, the printed matter 101 of this embodiment is provided with the modified layer 3, thereby enabling the adhesion between the base material layer 1 and the ink layer 4 to be improved.

[0124] <Applications> Compared to gravure printing and the like, offset printing has lower adhesion between the base layer and the ink layer. Therefore, when applied to packaging (light packaging) for confectionery and other products intended for use at room temperature, improved adhesion tends to be required. Furthermore, when applied to packaging for heating or moist heat, such as boiling or retorting, higher adhesion tends to be required to withstand the deterioration of adhesion due to heat. In this regard, the printed matter 101 of this embodiment is provided with a modified layer 3, thereby improving adhesion between the base layer 1 and the ink layer 4, thereby satisfying the adhesion requirements when applied to light packaging. Furthermore, it is also possible to satisfy the adhesion requirements when applied to packaging for heating or moist heat. Thus, the printed matter 101 can be suitably used not only for light packaging, but also for packaging that is heated or moist heat, such as boiled or retort foods, spout pouches, and microwaveable foods. In this case, examples of heat sterilization treatments applied to the printed matter 101 include retorting, boiling, and autoclaving. The temperature for the retort treatment may be, for example, 110 to 135°C, and the treatment time may be 5 to 120 minutes. The temperature for the boiling treatment may be, for example, 80 to 100°C, and the treatment time may be 5 to 120 minutes.

[0125] [Second embodiment] Fig. 3 is a cross-sectional view schematically showing the layer structure of a printed matter according to a second embodiment of the present invention. The printed matter 102 shown in Fig. 3 comprises, from the top (surface side), a base layer 1, an ink layer 4, a modified layer 3, and a sealant layer 2, in this order.

[0126] The printed matter 102 is a laminate formed by reverse offset printing. The printed matter 102 has the same configuration as the printed matter 101, except that it further includes a sealant layer 2 provided on a modified layer 3. The substrate layer 1, ink layer 4, and modified layer 3 provided in the printed matter 102 have the same configurations as those described in the first embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the first embodiment.

[0127] In the printed matter 102, the modified layer 3 also functions as an adhesive layer. The ink layer 4 cured by active energy rays is relatively hard and tends to have difficulty adhering to adjacent layers. However, by having the modified layer 3 function as an adhesive layer, the adhesion between the adjacent layers is improved.

[0128] <Sealant Layer> The sealant layer 2 may contain polyethylene, polypropylene, polyethylene terephthalate, polybutylene succinate (PBS), or the like. The polyethylene may be low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very-high-density polyethylene (VLDPE), with linear low-density polyethylene (LLDPE) being preferred. The polypropylene is preferably unstretched polypropylene (CPP). Polyethylene, polyethylene terephthalate, and polybutylene succinate are also preferably unstretched. As described above, the sealant layer 2 is preferably an unstretched film, but other stretched films such as heat-sealable oriented polypropylene (HSOPP) and heat-sealable polyethylene terephthalate (HSPET) can also be used.

[0129] From the viewpoint of reducing the environmental load, the polyethylene may be biomass-derived polyethylene or recycled polyethylene.

[0130] The sealant layer 2 may contain other additives. The content of polyethylene in the sealant layer 2 is preferably 50% by mass or more, and more preferably 80% by mass or more.

[0131] The sealant layer 2 may be transparent or opaque. When the printed matter 102 has a transparent sealant layer 2, the contents are easily visible when used in a package. When the printed matter 102 has an opaque sealant layer 2, the contents do not interfere with the visibility of information such as letters and images displayed in the ink layer 4 when used in a package. When the sealant layer 2 is opaque, the sealant layer 2 is preferably white, gray, black, or the like. These white, gray, black, or other colors of the sealant layer 2 can improve the visibility of information displayed in the ink layer 4.

[0132] When the printed matter 102 has the sealant layer 2 on the side of the modified layer 3 opposite to the ink layer 4, the modified layer 3 can function as an adhesive layer. In this case, the sealant layer 2 can be subjected to heat sealing.

[0133] The thickness of the sealant layer 2 can be appropriately set in consideration of the shape of the packaging bag to be manufactured, the mass of the contents to be contained, etc., and can be, for example, 5 to 150 μm.

[0134] The sealant layer 2 can be formed, for example, by laminating an unstretched polyethylene film directly onto the modified layer 3 or by extruding molten polyethylene onto the modified layer 3 .

[0135] The sealant layer 2 may contain titanium oxide. In this case, the sealant layer 2 can be configured as a light-blocking sealant layer for retort packaging. This suppresses the hardening and deterioration of polyethylene caused by light, thereby preventing a decrease in seal strength.

[0136] In this way, when the sealant layer 2 is provided on the side of the modified layer 3 opposite the ink layer 4 , the modified layer 3 can also function as an adhesive layer that bonds the base layer 1 and the sealant layer 2 together.

[0137] <Color Difference> The printed matter 102 deteriorates due to the heat of heat sealing, and this deterioration can manifest as a tint. It is preferable that the color difference (ΔE) of the printed matter 102, calculated by the following formula (A), before and after heating and pressurizing under heat sealing conditions of a temperature of 220°C, a pressure of 0.2 MPa, and a time of 1.5 seconds, is less than 3.0. By setting the color difference within the above range, the color difference before and after heat sealing can be reduced. As a result, the heat resistance of the printed matter 102 is improved.

[0138] [In the above formula (A), ΔL ＊ , Δa ＊ , and Δb ＊ is the L adopted in JIS Z 8781-4:2013 ＊ a ＊ b ＊ In the color space, the lightness (L ＊ ), chromaticity (a ＊ ), and saturation (b ＊ ) indicates the difference.

[0139] The upper limit of the color difference is preferably 1.5 or less, more preferably 1.3 or less, from the viewpoint of sufficiently suppressing discoloration during heat sealing. The lower limit of the color difference is preferably 0.1 or more, more preferably 0.3 or more, from the viewpoint of ease of production. When the printed matter 102 is viewed in plan from the substrate layer 1 side, the coverage ratio of the ink layer 4 to the entire region (area) subject to measurement of the color difference may be 50 area% or more, 70 area% or more, or even 100 area%. A coverage ratio of 100 area% means that the entire region subject to measurement of the "color difference" is covered by the ink layer 4. A coverage ratio of 50 area% means that half of the region subject to measurement of the "color difference" is covered by the ink layer 4.

[0140] Although the factors that can reduce the color difference before and after heat sealing are not clear, it is presumed that the components contained in the modified layer 3 have the effect of agglomerating the ink in the ink layer 4 to improve the strength of the ink layer 4 itself, and the effect of improving the adhesive strength between the ink layer 4 and an adjacent layer. This prevents gaps from occurring at the interface between the ink layer 4 and the modified layer 3, the ink layer 4 from moving and deforming, or the ink layer 4 from breaking. As a result, it is presumed that discoloration associated with the occurrence of gaps, deformation, and breakage is suppressed, and discoloration of the ink layer 4 is sufficiently suppressed.

[0141] <Discoloration Points> The number of discoloration points in the printed matter 102 can be an index of the heat resistance of the printed matter 102. When the sealant layer 2 is heated and pressed under heat sealing conditions of a temperature of 220°C, a pressure of 0.2 MPa, and a time of 1.5 seconds, the number of discoloration points having a size of 20 μm or more that occurs in the printed matter 102 is 1 mm ２ It is preferable that the number of particles is 10 or less per unit area. This prevents discoloration of the sealed portion and sufficiently prevents discoloration due to heat sealing. Therefore, the heat resistance of the printed matter 102 is improved.

[0142] <Relationship between Laminate Strength Change Rate and Ink Coverage Rate> The ink modifier in the modified layer 3 may have the function of forming urethane bonds and cross-linking the ink that forms the ink layer 4. This improves the adhesive strength between the ink layer 4 and the sealant layer 2 or an adjacent layer. Even if the ink coverage rate in the ink layer 4 increases, the epoxy compound can be sufficiently penetrated into the ink layer 4 by increasing the content of the epoxy compound contained in the ink modifier accordingly. The penetrated epoxy compound can cross-link the ink, thereby increasing the strength of the ink layer 4. Therefore, even if the ink coverage rate in the ink layer 4 increases, discoloration due to heat sealing is suppressed. Therefore, the heat resistance of the printed matter 102 is improved.

[0143] <Lamination Strength> The printed matter 102 preferably has an adhesive strength of 0.5 to 4.0 N / 15 mm as measured in accordance with JIS K 6854-1:1999. The adhesive strength can be measured, for example, by cutting the printed matter 102 to a width of 15 mm to prepare a measurement sample, peeling the layers at the edge of the measurement sample, and then measuring the peel strength between the layers of the laminate using a tensile tester at an angle of 90°, a tensile speed of 300 mm / min, and room temperature. This peel strength can be determined as the adhesive strength at room temperature (20°C). Setting the adhesive strength within the above range increases the laminate strength of the printed matter 102.

[0144] <Bag rupture resistance during heating> The printed material 102 is preferably such that the sealant layer 2 is heated and pressurized under heat-sealing conditions of a temperature of 220°C, a pressure of 0.2 MPa, and a time of 1.5 seconds to form a bag, and then heated in a microwave oven (output: 600 W) for 3 minutes without rupturing the sealed portion. This improves the heat resistance of the printed material 102, making it particularly suitable for use as a packaging material for food to be heated in a microwave oven.

[0145] <Peel Adhesion Strength> When the printed matter 102 is heated and pressurized under heat-sealing conditions of a temperature of 220°C, a pressure of 0.2 MPa, and a time of 1.5 seconds, and then exposed to a water vapor-containing atmosphere, the peel adhesion strength after the outer surface (the substrate layer 1 side) is S1 and the peel adhesion strength after the inner surface (the sealant layer 2 side) is S2, the ratio (S2 / S1) is preferably 0.6 to 1.6. This improves the heat resistance of the printed matter 102. This makes the printed matter 102 particularly suitable for use as a packaging material for retort pouch foods.

[0146] The printed matter 102 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 102 may be configured as a highly recyclable mono-material. Alternatively, even in the case of olefin-based resins, from the perspective of recycling, the printed matter 102 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, in an amount of 90% by mass or more.

[0147] As described above, the printed matter 102 of this embodiment includes the modified layer 3, which can improve the adhesion between the base material layer 1 and the ink layer 4. Furthermore, the provision of the modified layer 3 can further improve heat resistance.

[0148] <Applications> The printed matter 102 has improved adhesion between the base material layer 1 and the ink layer 4, as well as improved heat resistance, and therefore can be suitably used for boiled or retort foods (boiled or retort treatment), spout pouches (usually, welding of the sealant layer 2 in the welded portion and the non-sealed portion is performed by heating to 150°C or higher), cans, steam venting applications, and packages that are retorted and subjected to heating or moist heat, such as reheating in a microwave by the end consumer.

[0149] The printed matter 102 can also be used for packaging such as laminated tubes. In this case, for example, a second sealant layer (not shown) is further laminated on the upper side of the substrate layer 1 in the printed matter 102 in FIG. 3 (i.e., the side of the substrate layer 1 opposite the ink layer 4). This printed matter 102 includes, from the upper side (surface side), the second sealant layer, the substrate layer 1, the ink layer 4, the modified layer 3, and the sealant layer (first sealant layer) 2, in this order. This printed matter 102 is fed out and rolled into a cylindrical shape with the second sealant layer on the outer surface and the first sealant layer 2 on the inner surface, with the circumferential direction being the direction perpendicular to the machine direction (MD). The overlapping portions of the second sealant layer, which is the outermost layer, and the first sealant layer 2, which is the innermost layer, at both circumferential edge portions of the printed matter 102 are heat-sealed to form a cylindrical body tube. One axial end (i.e., flow direction) of the body tube is closed by heat welding to form a body that can be filled with contents. A resin shoulder is attached to the other (open) end of the body to form a laminated tube comprising a body and a shoulder. The first sealant layer 2 and the second sealant layer can be either a single layer or multiple layers, but from the viewpoint of processability, it is preferable to use an unstretched polyethylene (PE) film. The first sealant layer 2 and the second sealant layer may have the same or different structures.

[0150] [Third embodiment] Figure 4 is a cross-sectional view schematically showing the layer structure of a printed matter according to a third embodiment of the present invention. The printed matter 103 shown in Figure 4 is a laminate formed by reverse offset printing. The printed matter 103 comprises, from the top (surface side), a base layer 1, an ink layer 4, a modified layer 3, a barrier layer 5, an adhesive layer 7, and a sealant layer 2, in this order.

[0151] The printed matter 103 has the same configuration as the printed matter 102, except that it further includes a barrier layer 5 on the side of the modified layer 3 opposite the ink layer 4, and an adhesive layer 7 between the barrier layer 5 and the sealant layer 2. The substrate layer 1, ink layer 4, modified layer 3, and sealant layer 2 included in the printed matter 103 have the same configurations as those described in the second embodiment, and the printing method and the active energy ray irradiation method can also be the same as those in the second embodiment.

[0152] <Barrier Layer> The barrier layer (second barrier layer) 5 is, for example, a gas barrier layer that improves the oxygen barrier property and water vapor barrier property of the printed matter 103. The barrier layer 5 preferably includes an inorganic compound layer, or an inorganic compound layer and a coating layer. When the barrier layer 5 includes an inorganic compound layer and a coating layer, the inorganic compound layer and the coating layer are preferably laminated in this order from the modified layer 3 side. When microwave heating using a microwave oven is expected, the barrier layer 5 is preferably an inorganic oxide layer, a resin-containing layer, or a combination thereof.

[0153] <Inorganic Compound Layer> The inorganic compound layer may be formed by coating, or may be formed by vapor deposition of an inorganic compound.

[0154] Examples of inorganic compounds contained in the inorganic compound layer include metal oxides such as silicon oxide, boron oxide, aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, tin oxide, sodium oxide, titanium oxide, lead oxide, zirconium oxide, and yttrium oxide. The inorganic compound layer is preferably a vapor-deposited film made of a metal oxide. From the viewpoints of transparency and barrier properties, aluminum oxide, silicon oxide, and magnesium oxide are preferred as metal oxides. Furthermore, from the viewpoint of cost, aluminum oxide and silicon oxide are more preferred as metal oxides. Furthermore, from the viewpoint of excellent tensile stretchability during processing, silicon oxide is even more preferred as metal oxide. By using a vapor-deposited film made of a metal oxide as the inorganic compound layer, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the printed matter 103.

[0155] A vapor-deposited film made of metal oxide has transparency, and therefore has the advantage that, compared to a vapor-deposited film made of metal, users who handle packaging material made of printed matter are less likely to notice the metallic feel of the material.

[0156] The thickness of the vapor-deposited film made of aluminum oxide is preferably 5 to 30 nm, and more preferably 7 to 15 nm. By setting the thickness of the vapor-deposited film made of aluminum oxide to be equal to or greater than the above-mentioned lower limit, sufficient gas barrier properties can be obtained. By setting the thickness of the vapor-deposited film made of aluminum oxide to be equal to or less than the above-mentioned upper limit, the occurrence of cracks due to deformation caused by internal stress in the thin film can be suppressed, and deterioration of gas barrier properties can be suppressed. Note that even if the thickness of the vapor-deposited film exceeds the above-mentioned upper limit, the printed matter 103 itself can be used, but costs will increase due to increased material usage and longer film formation times.

[0157] The thickness of the vapor-deposited film made of silicon oxide is preferably 10 to 50 nm, more preferably 20 to 40 nm. By setting the thickness of the vapor-deposited film made of silicon oxide to be equal to or greater than the above-mentioned lower limit, sufficient gas barrier properties can be obtained. By setting the thickness of the vapor-deposited film made of silicon oxide to be equal to or less than the above-mentioned upper limit, the occurrence of cracks due to deformation caused by internal stress in the thin film can be suppressed, and deterioration of gas barrier properties can be suppressed. Note that even if the thickness of the vapor-deposited film exceeds the above-mentioned upper limit, the printed matter 103 itself can be used, but costs will increase due to increased material usage and longer film formation times.

[0158] The inorganic compound layer can be formed by, for example, vacuum film formation. In vacuum film formation, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD (Chemical Vapor Deposition), plasma CVD, and photo CVD.

[0159] In the vacuum film formation, resistance heating vacuum deposition, EB heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), etc. are preferably used. However, in consideration of productivity, vacuum deposition is preferred. As a heating means for vacuum deposition, it is preferable to use any one of electron beam heating, resistance heating, and induction heating.

[0160] <Coating Layer> The coating layer has gas barrier properties similar to the inorganic compound layer. The coating layer can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, or epoxy resin can be used. Organic particles or inorganic particles, an inorganic layered compound, a curing agent, etc. may be added to this coating liquid.

[0161] The coating layer may be, for example, an organic-inorganic composite layer containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further contain a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a hydrolyzate of a silane coupling agent, etc.

[0162] Examples of metal alkoxides and hydrolysates thereof contained in the organic-inorganic composite layer include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(OC ３ H ７ ) ３ ] and the like, general formula M(OR) ｎ and hydrolysates thereof. One of these may be used alone, or two or more may be used in combination.

[0163] In the coating liquid used to form the organic-inorganic composite layer, the total content of the metal alkoxide, its hydrolysate, or their reaction products is, for example, preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 65% ​​by mass or more, from the viewpoint of oxygen barrier property. The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid is, for example, preferably 70% by mass or less.

[0164] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving oxygen barrier properties, the water-soluble polymer preferably includes a polyvinyl alcohol-based polymer. The degree of polymerization of the water-soluble polymer is preferably, for example, 300 to 4500.

[0165] The polyvinyl alcohol polymer contained in the organic-inorganic composite layer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several percent to several tens of percent of residual acetate groups.

[0166] The content of the water-soluble polymer in the coating liquid used to form the organic-inorganic composite layer is preferably 15% by mass or more, more preferably 20% by mass or more, while the content of the water-soluble polymer in the coating liquid used to form the organic-inorganic composite layer is preferably 50% by mass or less, more preferably 45% by mass or less.

[0167] Examples of silane coupling agents used in the organic-inorganic composite layer include silane coupling agents having an organic functional group. Examples of silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. A silane coupling agent selected from these, its hydrolyzate, or a reaction product thereof may be used alone, or two or more may be used in combination.

[0168] The silane coupling agent preferably has an epoxy group as the organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group may have an organic functional group other than the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group. A silane coupling agent selected from these, its hydrolyzate, or a reaction product thereof may be used alone, or two or more may be mixed and used.

[0169] Silane coupling agents having organic functional groups, their hydrolyzates, and their reaction products further enhance the oxygen barrier properties of the coating layer and the adhesion to adjacent layers due to the interaction between the organic functional groups and the hydroxy groups of the water-soluble polymer. In particular, when the silane coupling agent, its hydrolyzate, or its reaction product has an epoxy group and the water-soluble polymer is polyvinyl alcohol, the oxygen barrier properties and the adhesion to adjacent layers are further enhanced due to the interaction between the epoxy group and the hydroxy groups of the polyvinyl alcohol.

[0170] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid used to form the organic-inorganic composite layer is preferably 1% by mass or more, more preferably 2% by mass or more, while the total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid is preferably 15% by mass or less, more preferably 12% by mass or less.

[0171] The thickness of the coating layer is preferably 50 to 1,000 nm, more preferably 100 to 500 nm. By setting the thickness of the coating layer to the above lower limit or more, more sufficient gas barrier properties can be obtained, and by setting the thickness to the above upper limit or less, sufficient flexibility can be maintained.

[0172] The barrier layer 5 is preferably subjected to a surface treatment, as in the case of the substrate layer 1 of the first embodiment described above. This can improve the adhesion between the barrier layer 5 and the adjacent layer. Note that a nanocomposite may also be used as the material for the barrier layer 5.

[0173] <Adhesive Layer> The adhesive layer 7 bonds the barrier layer 5 and the sealant layer 2. As the adhesive layer 7, a layer having a configuration similar to that of the modified layer 3 of the first embodiment may be used. Alternatively, an adhesive layer 7 containing an adhesive such as that described below may be used.

[0174] The adhesive layer 7 includes at least one type of adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may also be a solventless adhesive or a solvent-based adhesive.

[0175] Examples of adhesives for forming the adhesive layer 7 include polyether adhesives, polyester adhesives, silicone adhesives, polyamine adhesives, adhesives to which epoxy groups have been added, urethane adhesives, rubber adhesives, vinyl adhesives, epoxy adhesives other than those mentioned above, phenol adhesives, and olefin adhesives. Adhesives containing biomass components can also be preferably used. Polyamine adhesives and urethane adhesives are more preferred adhesives. The adhesive may have gas barrier properties. One type of adhesive may be used alone, or two or more types may be used in combination. Specific examples of gas barrier adhesives include "Maxieve (registered trademark)" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim (registered trademark)" manufactured by DIC Corporation.

[0176] The thickness of the adhesive layer 7 is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm.

[0177] The adhesive layer 7 can be formed by applying and drying on the sealant layer 2 using a conventionally known method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0178] The printed matter 103 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 103 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 103 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, in an amount of 90% by mass or more.

[0179] As described above, the printed matter 103 of this embodiment has the same effects as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment. In addition, the printed matter 103 also has the above-described effects attributable to the barrier layer 5.

[0180] <Use> The printed matter 103 can be used for the same purposes as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment.

[0181] [Fourth embodiment] Figure 5 is a cross-sectional view schematically showing the layer structure of a printed matter according to a fourth embodiment of the present invention. The printed matter 104 shown in Figure 5 is a laminate formed by reverse offset printing. The printed matter 104 comprises, from the top (surface side), a protective layer 6, a substrate layer 1, an ink layer 4, a modified layer 3, and a sealant layer 2, in this order.

[0182] The printed matter 104 has the same configuration as the printed matter 102, except that it further includes a protective layer 6 on the surface of the substrate layer 1. The substrate layer 1, ink layer 4, modified layer 3, and sealant layer 2 included in the printed matter 104 have the same configurations as those described in the second embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the second embodiment.

[0183] <Protective Layer> The printed matter 104 includes a protective layer 6 as the outermost layer. The protective layer 6 is formed on at least a portion of the outer layer side of the transparent substrate layer 1. The protective layer 6 may be a transparent resin layer, and the resin is not particularly limited. When the printed matter 104 is a metallic printed matter having a metallic reflective layer, the protective layer 6 is preferably formed in a position where the protective layer 6 overlaps at least a portion of the area where the metallic reflective layer is present when the printed matter 104 is viewed in plan. By arranging the protective layer 6 so that it overlaps at least a portion of the area where the metallic reflective layer is present in the planar direction, the metallic luster based on the metallic reflective layer can be adjusted, improving the design. Furthermore, by arranging the protective layer 6 so that it overlaps at least a portion of the area where the metallic reflective layer is present in the planar direction, and by arranging the internal scattering layer so that it overlaps at least a portion of the area where the protective layer 6 is present, even if the surface is scratched, traces of the scratch are not noticeable, and a decrease in design can be suppressed. The protective layer 6 may be arranged so as to overlap the entire area having the metal reflective layer in the planar direction, but from the viewpoint of creating a contrast in metallic luster depending on whether the protective layer 6 is present or not, it is preferable to arrange it so as to overlap only a portion of the area having the metal reflective layer.

[0184] The printed matter 104 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 104 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 104 may have a mono-olefin configuration in which, for example, the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0185] As described above, the printed matter 104 of this embodiment has the same effects as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment. In addition, the printed matter 104 also has the above-described effects attributable to the protective layer 6.

[0186] <Use> The printed matter 104 can be used for the same purposes as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment.

[0187] [Fifth embodiment] Figure 6 is a cross-sectional view schematically showing the layer structure of a printed matter according to a fifth embodiment of the present invention. The printed matter 105 shown in Figure 6 is a laminate formed by reverse offset printing. The printed matter 105 comprises, from the top (surface side), a base layer 1, an ink layer 4, a modified layer 3, an intermediate layer 8, an adhesive layer 7, and a sealant layer 2, in this order.

[0188] The printed matter 105 has the same configuration as the printed matter 103, except that it has an intermediate layer 8 between the modified layer 3 and the adhesive layer 7 instead of the barrier layer 5. The base material layer 1, ink layer 4, modified layer 3, adhesive layer 7, and sealant layer 2 of the printed matter 105 have the same configurations as those described in the third embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the third embodiment.

[0189] <Intermediate Layer> The intermediate layer 8 may contain a polyolefin resin such as polyethylene, polypropylene, polystyrene, or polymethylpentene, an alicyclic polyolefin resin, a polyamide resin such as nylon 6 or nylon 66, a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polypropylene terephthalate, polybutyl succinate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, or polyethylene diphenylate, a polycarbonate resin, a polyarylate resin, a polyacetal resin, a polyphenylene sulfide resin, a fluorine-based resin such as trifluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer, or vinylidene fluoride resin, an acrylic resin, a methacrylic resin, a polyacetal resin, a polyglycolic acid resin, or a polylactic acid resin. The resin contained in the intermediate layer 8 may be the same as or different from the resin contained in the base layer 1. The intermediate layer 8 may be an aluminum-deposited resin film in which an aluminum-deposited layer is formed on a resin film. The intermediate layer 8 may also contain aluminum foil. By including aluminum foil in the intermediate layer 8, it is possible to impart a metallic luster to the printed matter 105 and improve the barrier properties. Furthermore, the intermediate layer 8 may have the same configuration as the base material layer 1 of the first embodiment.

[0190] The thickness of the intermediate layer 8, like the base layer 1, is preferably 5 to 200 μm, more preferably 6.5 to 100 μm, even more preferably 7 to 50 μm, and particularly preferably 7 to 35 μm.

[0191] The intermediate layer 8 may be colored, and may be white, gray, black, or the like.

[0192] The printed matter 105 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 105 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 105 may have a mono-olefin configuration in which, for example, the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0193] As described above, the printed matter 105 of this embodiment has the same effects as the printed matter 103 of the third embodiment. In addition, the above-described effects attributable to the intermediate layer 8 are also achieved.

[0194] <Use> The printed matter 105 can be used for the same purposes as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment.

[0195] [Sixth embodiment] Figure 7 is a cross-sectional view schematically showing the layer structure of a printed matter according to a sixth embodiment of the present invention. The printed matter 106 shown in Figure 7 is a laminate formed by surface offset printing. The printed matter 106 comprises, from the top (surface side), a modified layer 3, an ink layer 4, and a substrate layer 1, in this order.

[0196] The printed matter 106 is obtained by applying ink onto the base material layer 1 by printing, applying a modified layer 3 onto the ink layer 4 before irradiating it with active energy rays, and then irradiating the base material layer 1, ink layer 4, and modified layer 3 in a laminated state with active energy rays from the modified layer 3 side to harden them. The ink layer 4 of the printed matter 106 has the same configuration as that described in the first embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the first embodiment.

[0197] As described above, in offset printing, the surface of the ink layer is not necessarily smooth due to the printing method and the leveling properties of the ink, and it is presumed that the presence of fine air bubbles in the ink causes gaps between the ink particles and that air bubbles are mixed into the ink particles. Even if an ink modifier is applied to the ink layer 4 before irradiation with active energy rays, it is presumed that the ink modifier penetrates into the gaps between the ink particles of the cured ink layer 4 and the air bubbles within the ink particles when irradiated with active energy rays, and that irradiation with active energy rays in this state improves the adhesion between the ink particles and between the substrate layer 1 and the ink layer 4, as in the first embodiment.

[0198] <Substrate Layer> A resin film having the same configuration as in the first to fifth embodiments can be used as the substrate layer 1. On the other hand, in the printed matter 106, the substrate layer 1 is not required to be transparent, which increases the degree of freedom in the substrate layer 1. For example, the substrate layer 1 may be colored or milky white.

[0199] Here, offset printing tends to print ink thicker than gravure printing, but white spots are more likely to occur and the hiding power tends to be reduced. Reducing the viscosity of the ink is considered as a method for improving hiding power, but reducing the viscosity may reduce the adhesion between the substrate layer 1 and the ink layer 4. On the other hand, as described above, increasing the viscosity of the ink may reduce the ink's fluidity, dispersibility, leveling properties, etc., and may reduce the printing accuracy (reproducibility). However, if the substrate layer 1 is milky white, the adhesion can be improved without reducing the ink's viscosity. Furthermore, white printing is not required, which can reduce the number of printing steps. The hiding power of the substrate layer 1 is preferably 40% or more, more preferably 50% or more.

[0200] <Paper Sheet> A paper sheet can also be used as the base layer 1. The paper sheet may include a paper layer and a clay-coated layer. The paper layer may be made primarily of plant-derived pulp. Specific examples of paper sheets include fine paper, special fine paper, coated paper, art paper, cast-coated paper, construction paper, kraft paper, and glassine paper.

[0201] The basis weight of the paper sheet is 20 to 500 g / m ２ is preferred, and 30 to 200 g / m ２ is more preferred.

[0202] The thickness of the paper sheet is preferably 20 to 150 μm, more preferably 30 to 100 μm.

[0203] The paper sheet may comprise a metallized layer laminated to the paper layer or the clay coat layer.

[0204] <Vapor-deposited layer> The vapor-deposited layer is a layer formed by vapor-depositing a metal or an inorganic compound. For example, a vapor-deposited layer formed by vapor-depositing aluminum can be used. The vapor-deposited layer can be formed by vapor-depositing aluminum oxide (AlO ｘ ), silicon oxide (SiO ｘ ) etc.

[0205] The paper sheet is not limited to one in which a vapor-deposited layer is formed on a paper layer, but may be one in which a paper layer and a metal (for example, aluminum foil) are bonded together with an adhesive.

[0206] <Modified Layer> In the printed matter 106, the modified layer 3 is a transparent layer that protects the ink layer 4 and also functions as a surface protection layer (overcoat layer). The modified layer 3 contains a transparent active energy ray-curable resin as an ink modifier. As the active energy ray-curable resin, a transparent resin whose main component is a prepolymer (including an oligomer) and / or a monomer containing a radically polymerizable double bond in the molecule that crosslinks (cures) when irradiated with active energy rays such as an electron beam can be used. Here, "main component" means that the main component is 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more.

[0207] Specifically, examples of prepolymers and monomers include compounds having, in the molecule, a radically polymerizable unsaturated group such as a (meth)acryloyl group or a (meth)acryloyloxy group, or a cationically polymerizable functional group such as an epoxy group, etc. Here, the (meth)acryloyl group means an acryloyl group and / or a methacryloyl group.

[0208] Examples of prepolymers having a radically polymerizable unsaturated group include polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, triazine (meth)acrylate, and silicone (meth)acrylate. The weight average molecular weight (Mw) of these prepolymers is preferably about 250 to 100,000. The weight average molecular weight (Mw) is measured using gel permeation chromatography (GPC) in terms of polystyrene.

[0209] Examples of the monomer having a radically polymerizable unsaturated group include monofunctional monomers such as methyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and phenoxyethyl(meth)acrylate. Examples of the polyfunctional monomers include diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0210] Examples of prepolymers having a cationically polymerizable functional group include prepolymers of epoxy resins such as bisphenol-type epoxy resins and novolac-type epoxy compounds, and vinyl ether resins such as fatty acid vinyl ethers and aromatic vinyl ethers. Polyene / thiol-based prepolymers, which are combinations of polyenes and polythiols, are also preferred. Examples of thiols include polythiols such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate. Examples of polyenes include those in which allyl alcohol is added to both ends of a polyurethane made from a diol and a diisocyanate.

[0211] The ink modifier preferably contains an acrylic resin. When the ink modifier contains an acrylic resin, the modified layer 3 can also function as a surface protection layer (overcoat layer) that protects the surface of the ink layer 4.

[0212] The transparent active energy ray-curable resin may be used alone or in combination of two or more.

[0213] The thickness of the modified layer 3 is preferably 0.1 to 10 μm. By setting the thickness of the modified layer 3 to the above-mentioned lower limit or more, various resistances such as scratch resistance, abrasion resistance, and weather resistance are improved. By setting the thickness of the modified layer 3 to the above-mentioned upper limit or less, there is no need to use an unnecessarily large amount of resin material, thereby reducing costs.

[0214] The printed matter 106 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 106 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 106 may have a mono-olefin configuration in which, for example, the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0215] As described above, in the printed matter 106 of this embodiment, the substrate layer 1 has affinity with the active energy ray-curable resin, and the ink layer 4 contains the active energy ray-curable resin, so that the adhesion between the substrate layer 1 and the ink layer 4 can be improved.

[0216] <Use> The printed matter 106 can be used for the same purposes as the printed matter 101 of the first embodiment.

[0217] [Seventh embodiment] Figure 8 is a cross-sectional view schematically showing the layer structure of a printed matter according to a seventh embodiment of the present invention. The printed matter 107 shown in Figure 8 is a laminate formed by surface offset printing. The printed matter 107 comprises, from the top (surface side), a modified layer 3, an ink layer 4, a substrate layer 1, an adhesive layer 7, and a sealant layer 2, in this order.

[0218] The printed matter 107 has the same configuration as the printed matter 106, except that a sealant layer 2 is provided on the substrate layer 1 on the side opposite the ink layer 4, via an adhesive layer 7. The substrate layer 1, ink layer 4, and modified layer 3 of the printed matter 107 have the same configurations as those described in the sixth embodiment, the adhesive layer 7 has the same configuration as that described in the third embodiment, and the sealant layer 2 has the same configuration as that described in the second embodiment, and the printing method and the active energy ray irradiation method can also be the same as those in the sixth embodiment.

[0219] By providing the printed matter 107 with a sealant layer 2 on the side of the modified layer 3 opposite the ink layer 4 via an adhesive layer 7, it is possible to protect the surface of the ink layer 4 on one side with the modified layer 3 while the sealant layer 2 on the other side can be heat-sealed.

[0220] The printed matter 107 may contain 90% by mass or more of the same type of resin (e.g., polyethylene, etc.). In this case, the printed matter 107 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 107 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, in an amount of 90% by mass or more.

[0221] As described above, the printed matter 107 of this embodiment can improve the adhesion between the base material layer 1 and the ink layer 4. In addition, the effects of providing the sealant layer 2 can be achieved.

[0222] <Uses> The printed matter 107 can be used for the same purposes as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment. When the printed matter 107 is used in a package such as a laminated tube as in the second embodiment, for example, a second sealant layer (not shown) is further laminated on the upper side of the substrate layer 1 in the printed matter 107 of FIG. 8 (i.e., the ink layer 4 side of the substrate layer 1). This printed matter 107 includes, from the upper side (surface side), a modified layer 3, an ink layer 4, a second sealant layer, a substrate layer 1, an adhesive layer 7, and a sealant layer (first sealant layer) 2, in this order. This laminated tube can be formed in the same manner as the laminated tube of the second embodiment, and the first sealant layer and the second sealant layer can also have the same configuration as the laminated tube of the second embodiment.

[0223] [Printed Medium] The present inventors have discovered the following about the adhesion between the substrate layer and the ink layer. That is, when active energy rays are irradiated onto ink printed on a substrate layer, the active energy rays are irradiated not only onto the ink layer but also onto the substrate layer. Conventionally, it has been thought that as the exposure dose of active energy rays increases, the crosslinking density between the resin constituting the substrate layer and the resin contained in the ink increases. According to this concept, the higher the exposure dose, the stronger the adhesion between the substrate layer and the ink layer. Furthermore, the strength of the printed matter will also be increased.

[0224] However, the present inventors have found that increasing the irradiation dose does not necessarily increase the adhesion, strength, flexibility, etc. in proportion to the increase in the irradiation dose, and that if the irradiation dose is too high, the crosslinking density tends to decrease, and the adhesion, strength, and flexibility tend to decrease.

[0225] The reason for this is unclear, but is presumed to be as follows. That is, for example, when a resin having a crystalline portion with a crystalline structure and an amorphous portion with an amorphous structure (e.g., polyethylene (PE) or the like) is used as the base layer, crosslinking tends to occur in the amorphous portion. In this case, in a resin with a relatively low branched structure (e.g., high-density polyethylene (HDPE) or the like), if the irradiation dose is too high, molecular weight degradation occurs, and adhesion and strength tend to decrease. On the other hand, in a resin with a relatively high branched structure (e.g., linear low-density polyethylene (LLDPE) or the like), it is presumed that crosslinking occurs between amorphous portions, resulting in less crosslinking with other layers, and therefore adhesion and strength decrease. Thus, the fact that an excessively high irradiation dose can actually have a negative effect on adhesion, strength, etc. is a previously unknown phenomenon and a new finding.

[0226] The reason for this phenomenon is thought to be that by keeping the exposure dose low, cross-linking (covalent bonding) in the substrate layer is suppressed, and between the substrate layer and the ink layer, interactions weaker than cross-linking, such as electrostatic interactions (ionic bonds, hydrogen bonds, dipole interactions, van der Waals forces, etc.), work, thereby enhancing the adhesion between the substrate layer and the ink layer. Furthermore, it is thought that by suppressing unnecessary cross-linking within the substrate layer, the strength, flexibility, etc. of the substrate layer are also enhanced.

[0227] Here, when producing a packaging body from a printed matter subjected to offset printing, the ink layer laminated on the printed matter is required to have strength and flexibility. However, increasing the hardness of the ink layer in order to improve strength may result in a decrease in flexibility, while increasing flexibility too much may result in a decrease in strength. As such, strength and flexibility are mutually exclusive properties, and it has been thought that it is difficult to simultaneously increase strength and flexibility in a printed matter. However, by appropriately adjusting the irradiation conditions of the active energy rays as described above, it is possible to increase strength and flexibility while improving adhesion.

[0228] [Eighth embodiment] Figure 9 is a cross-sectional view schematically showing the layer structure of a printed matter according to an eighth embodiment of the present invention. The printed matter 108 shown in Figure 9 is a laminate formed by reverse offset printing. The printed matter 108 comprises, from the top (surface side), a protective layer 6, a base material layer 1, an ink layer 4, a modified layer 3, and a sealant layer 2, in this order.

[0229] The printed matter 108 has a configuration that is particularly preferable for achieving mono-materialization of the printed matter 104. The printed matter 108 basically has the same configuration as the printed matter 104 described in the fourth embodiment, and the same printing method and active energy ray irradiation method as those in the fourth embodiment can be adopted, but supplementary explanations regarding the configuration of the printed matter 104 and more preferable configurations will be described below.

[0230] <Ink Layer> The ink layer 4 provides the laminate with information about the contents, various designs, and the like. In the reverse-printed printed matter 108, the ink layer 4 is not exposed to the outer surface when the product is made into a packaging material, thereby suppressing damage and deterioration of the display after production. By forming the ink layer 4 over the entire substrate layer 1 using a light-blocking ink, the contents can be protected from light. Such a light-blocking ink layer can be produced, for example, by overprinting a chromatic ink containing a white pigment and a black pigment, with the proportion of black pigment in the total pigment being 3 to 5% by weight, on a single or multiple white ink layer 4 formed by full-surface printing (solid printing), thereby forming a chromatic ink layer with a saturation of 1 to 4 on the Munsell color system. The ink layer 4 can be provided with light-blocking properties while freely designing its appearance by combining a light-blocking ink layer with an ink layer (image printing layer) containing designs, letters, etc., made of ink that does not have light-blocking properties. In this case, the visibility of the image can be improved by first forming an image print layer on the base material layer 1 and then forming a light-blocking ink layer. The ink layer 4 is preferably formed from a biomass-derived ink. This allows the printed matter 108 to be used to produce packaging materials with a lower environmental impact. The method for forming the image is not particularly limited, and examples include various conventionally known printing methods such as gravure printing, offset printing, and flexographic printing. Of these, the offset printing method described above is preferred from the viewpoint of irradiating electron beams.

[0231] Of the inks that form the ink layer 4, known color inks (for example, red ink, yellow ink, indigo ink, black ink, and white ink) can be used as color inks.

[0232] The type of pigment contained in the color inks other than the white ink may be determined appropriately depending on the color to be expressed. For example, inorganic pigments or organic pigments may be used as the pigment. Examples of inorganic pigments include carbon black (black ink pigment). Examples of organic pigments include azo pigments, phthalocyanine pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, and dye lake pigments. A combination of multiple pigments may be used as the pigment.

[0233] Examples of materials constituting the pigment contained in the white ink include inorganic oxides such as titanium oxide, alumina, mica, lead oxide (white lead), zinc oxide, calcium carbonate, barium carbonate, barium sulfate, kaolin, potassium titanate, talc, magnesium hydroxide, natural silica, and synthetic silica (white carbon). Among these, pigments containing titanium oxide are preferably used from the viewpoints of hiding power and dispersibility upon addition. Titanium oxide may be of the rutile or anatase type. The surface of the titanium oxide-containing pigment may be treated with a metal oxide such as aluminum (Al) or silicon (Si). The average particle size of the white pigment can be selected within a range that does not interfere with the objectives of the present disclosure.

[0234] Examples of binder resins include alkyd resins, phenolic resins, maleic acid resins, natural resins, hydrocarbon resins, polyvinyl chloride resins, polyacetic acid resins, polystyrene resins, polyvinyl butyral resins, acrylic or methacrylic resins, polyamide resins, polyester resins, polyurethane resins, epoxy resins, urea resins, melamine resins, nitrocellulose, ethyl cellulose, etc. These may be used alone or in combination of two or more.

[0235] The ratio of the pigment content to the binder resin content (pigment / resin ratio) is, for example, 1.6 or less by mass, and preferably 0.5 to 1.6. A better appearance is likely to be obtained when the mass ratio (pigment / resin ratio) is 1.6 or less.

[0236] The ink may consist solely of white ink, or may consist solely of colored inks other than white ink, or may consist of colored inks other than white ink and colorless ink (ink not containing pigment). The ink forming the ink layer 4 may contain a white ink containing a smaller amount of pigment than white ink used for the purpose of improving light-blocking and hiding properties (for example, a white ink in which the ratio of the pigment content to the binder resin content (pigment / resin ratio) is 0.5 to 1.6 by mass). From the viewpoint of reducing minute voids caused by gaps between pigments formed in the ink layer 4 and obtaining a better appearance, the ink does not have to contain white ink.

[0237] <Substrate Layer> The substrate layer 1 has a main substrate layer 10 having three layers, in this order: a first skin layer 11 on the side opposite the sealant layer 2, a core layer 12, and a second skin layer 13 on the sealant layer 2 side, each containing polyethylene; and an inorganic oxide layer 16 following the second skin layer 13 of the main substrate layer 10. The substrate layer 1 may further have a gas barrier coating layer 17 or an anchor coat layer, which will be described later. The main substrate layer 10 does not necessarily have to have the first skin layer 11. The first skin layer 11 and the second skin layer 13 can each be the outermost layer of the main substrate layer 10. The main substrate layer 10 is a multilayer film that can be obtained by coextrusion, and therefore can also be called a coextruded multilayer film.

[0238] From the viewpoint of more easily achieving both printability and impact resistance, the core layer 12 and the second skin layer 13 can be laminated adjacent to each other. From the same viewpoint, the core layer 12 and the first skin layer 11 can be laminated adjacent to each other.

[0239] The main substrate layer 10 may include layers other than the three layers of the first skin layer 11, the core layer 12, and the second skin layer 13. For example, a resin layer may be provided between the core layer 12 and the second skin layer 13, or another resin layer may be provided between the first skin layer 11 and the core layer 12. The resin layer may, for example, contain polyethylene and have a different composition from the core layer 12 and the second skin layer 13. The other resin layer may, for example, contain polyethylene and have a different composition from the first skin layer 11 and the core layer 12. The resin layer and the other resin layer may also be referred to as adhesive resin layers because they have the function of adhering different layers (between the core layer and the skin layer). The main substrate layer 10 may, for example, have three, five, seven, or more layers (preferably layers containing polyethylene).

[0240] The polyethylene content in the main substrate layer 10 may be 90% by mass or more, or 95% by mass or more, based on the total amount of the main substrate layer 10, from the viewpoint of realizing mono-materialization and excellent recyclability.

[0241] The main substrate layer 10 may be a stretched film or a non-stretched film. When the main substrate layer 10 is a stretched film, it is easy to obtain a printed matter 108 having good printability and impact resistance. Examples of stretched films include uniaxially stretched films and biaxially stretched films, but from the viewpoint of impact resistance, biaxially stretched films are preferred.

[0242] The thickness of the main substrate layer 10 is not particularly limited and can be appropriately determined according to cost and application, taking into consideration suitability as a packaging material and suitability for lamination with other layers. The thickness of the main substrate layer 10 may be 3 μm or more, 5 μm or more, 6 μm or more, or 10 μm or more, or may be 200 μm or less, 120 μm or less, 100 μm or less, or 40 μm or less.

[0243] (Core Layer) The core layer 12 is a layer containing polyethylene. Hereinafter, the polyethylene constituting the core layer 12 will also be referred to as the first polyethylene. The content of the first polyethylene in the core layer 12 may be 90% by mass or more, 95% by mass or more, or 98% by mass or more, based on the total amount of the core layer 12, or may be 100% by mass (an embodiment in which the core layer 12 is essentially composed of the first polyethylene). When the core layer 12 is composed of multiple polyethylenes (e.g., multiple polyethylenes with different average molecular weights, densities, etc.), a mixture of the multiple polyethylenes is referred to as the first polyethylene. The first polyethylene may be a high-density polyethylene resin (HDPE).

[0244] The core layer 12 has a probe drop temperature of more than 180° C. from the viewpoint of being less likely to wrinkle when heated and having better printing stability (heat resistance). The probe drop temperature is a value measured by the method described below.

[0245] The higher the probe drop temperature of the core layer 12, the easier it is to achieve excellent printability. The probe drop temperature of the core layer 12 may be 185°C or higher, 190°C or higher, or 200°C or higher, from the viewpoint of reducing wrinkles and improving printability. On the other hand, the probe drop temperature of the core layer 12 may be 250°C or lower, 230°C or lower, or 220°C or lower, from the viewpoint of impact resistance.

[0246] The tip drop temperature is a parameter related to localized thermal analysis of materials using a probe and can be obtained by measuring the tip's rise and fall behavior. To measure the tip drop temperature, an atomic force microscope (AFM) equipped with a cantilever (probe) with a heating mechanism and a nanothermal microscope is used. The cantilever is placed in contact with the surface of a solid sample fixed to a sample stage. When a voltage is applied to the cantilever in contact mode to heat the sample, the sample surface thermally expands, causing the cantilever to rise. Further heating of the cantilever softens the sample surface, significantly changing its hardness. As a result, the cantilever descends and penetrates the sample surface. The point at which the sudden displacement detected at this time begins is the tip drop start point, and the voltage is converted to temperature to obtain the tip drop temperature. This method allows the tip drop temperature to be determined locally in the nanoscale region, near the surface.

[0247] Examples of AFMs that can be used include the MPF-3D-SA and Ztherm systems manufactured by Oxford Instruments, and the Nano Thermal Analysis series and nanoIR series manufactured by Bruker Japan. Measurements are also possible with AFMs from other manufacturers if a Nano Thermal Analysis is attached. An example of a cantilever is the AN2-200 manufactured by Anasys Instruments. Cantilevers other than those listed above can also be used, as long as they can sufficiently reflect laser light and allow voltage to be applied.

[0248] The temperature range for measuring the probe drop temperature varies depending on the material to be measured, but for example, the starting temperature can be about room temperature, 25° C., and the ending temperature can be about 400° C. The temperature range for measuring the probe drop temperature may be from 25° C. to 300° C.

[0249] The spring constant of the cantilever may be 0.1 to 3.5 N / m, and is preferably 0.5 to 3.5 N / m for measurements in both tapping mode and contact mode. In AFM, the deflection of the cantilever is sometimes measured in units of voltage. In contact mode, the deflection of the cantilever changes before and after contact between the cantilever and the sample. By keeping this change within the range of 0.1 to 3.0 V, it is possible to prevent damage to the sample surface while keeping the cantilever in contact with the sample.

[0250] The temperature rise rate of the cantilever varies depending on the heating mechanism, etc., but may be 0.1 to 10 V / sec, and preferably 0.2 to 5 V / sec. When the sample surface softens, the tip of the cantilever sinks into the sample and descends. The amount of sinking of the cantilever affects the detection sensitivity of the peak top of the softening curve, and can be set to 3 to 500 nm. From the viewpoint of preventing damage to the cantilever, it is more preferable to set the amount of sinking to 5 to 100 nm.

[0251] In order to calculate the probe drop temperature, it is necessary to create a calibration curve. In the examples described below, calibration curves were created using polycaprolactone, low-density polyethylene, polypropylene, and polyethylene terephthalate as calibration samples. The materials of the calibration samples are not limited to those mentioned above; they may be any material whose thermal conductivity is not significantly different from that of common polymers and whose melting point is at least one of approximately 60°C, approximately 250°C, and an intermediate melting point. For example, it is also possible to remove polypropylene from the four calibration samples mentioned above and use only the three materials of polycaprolactone, low-density polyethylene, and polyethylene terephthalate as calibration samples.

[0252] The core layer 12 having the desired probe drop temperature can be obtained, for example, by adjusting the density, melt flow rate (MFR), stretching ratio, heat treatment / cooling conditions, etc. of the first polyethylene during film formation, or by subjecting the core layer 12 to treatment such as annealing or electron beam (EB) irradiation.

[0253] The density of the first polyethylene is not particularly limited, but is preferably 0.942 g / cm ３ Above, 0.945g / cm ３ or more, or 0.950 g / cm ３ or more, and 0.980 g / cm ３ Below, 0.975g / cm ３ Below, 0.970g / cm ３ or less, or 0.965 g / cm ３ The density of the resin (resin film) is a value measured in accordance with JIS Z 8837:2018.

[0254] The melt flow rate (MFR) of the first polyethylene at 190°C under a load of 2.16 kg is not particularly limited, but may be 10 g / 10 min or less, 5 g / 10 min or less, 3 g / 10 min or less, or 2 g / 10 min or less, or may be 0.1 g / 10 min or more, 0.3 g / 10 min or more, or 0.5 g / 10 min or more. The melt flow rate of the resin (resin film) is a value measured in accordance with JIS K6921-2:2018.

[0255] From the viewpoint of achieving both heat resistance and impact resistance, the difference between the probe drop temperature of the core layer 12 and the probe drop temperature of the first skin layer 11 and / or the second skin layer 13 may be 10° C. or more, 30° C. or more, or 40° C. or more. On the other hand, from the viewpoint of interlayer adhesion between the core layer 12 and the second skin layer 13, the difference between the probe drop temperature of the core layer 12 and the probe drop temperature of the first skin layer 11 and / or the second skin layer 13 may be 100° C. or less, 70° C. or less, or 50° C. or less.

[0256] The thickness of the core layer 12 is not particularly limited and can be appropriately determined according to the cost and application, taking into consideration the suitability of the manufacturing method and apparatus, and the suitability for lamination with other layers. From a practical standpoint, the thickness of the core layer 12 may be 5 μm or more, 8 μm or more, 10 μm or more, 12 μm or more, or 15 μm or more, or may be 80 μm or less, 50 μm or less, 40 μm or less, or 30 μm or less.

[0257] From the viewpoint of reducing the occurrence of wrinkles and improving printing stability, the thickness of the core layer 12 may be 33% or more, 40% or more, 50% or more, 55% or more, or 60% or more of the thickness of the main substrate layer 10. On the other hand, from the viewpoint of achieving better impact resistance, the thickness of the core layer 12 may be 90% or less, 85% or less, or 80% or less of the thickness of the main substrate layer 10.

[0258] From the viewpoint of reducing the occurrence of wrinkles and improving printing stability, the thickness of core layer 12 may be greater than the thickness of first skin layer 11 and / or second skin layer 13. The thickness of core layer 12 may be more than 1 time, 1.5 times or more, 2 times or more, or 3 times or more the thickness of first skin layer 11 and / or second skin layer 13. On the other hand, from the viewpoint of achieving better impact resistance, the thickness of core layer 12 may be 20 times or less, 10 times or less, or 5 times or less the thickness of first skin layer 11 and / or second skin layer 13.

[0259] The first skin layer 11, the core layer 12, and the second skin layer 13 may contain a resin other than polyethylene as long as it does not impair recyclability. Examples of such resins include olefin-based resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, ethylene-(meth)acrylic acid copolymer, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α-olefin copolymer, polybutene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, ethylene-vinyl alcohol copolymer, polyamide, and various modifying resins. Each layer may also independently contain one or more additives. Examples of additives include crosslinkers, antioxidants, antiblocking agents, lubricants (slip agents), UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments.

[0260] (Second Skin Layer) The second skin layer 13 is a layer containing polyethylene. Hereinafter, the polyethylene constituting the second skin layer 13 is also referred to as the second polyethylene. The content of the second polyethylene in the second skin layer 13 may be 90% by mass or more, 95% by mass or more, or 98% by mass or more, based on the total amount of the second skin layer 13, or may be 100% by mass (an embodiment in which the second skin layer 13 is essentially composed of the second polyethylene). When the second skin layer 13 is composed of multiple polyethylenes (e.g., multiple polyethylenes with different average molecular weights, densities, etc.), a mixture of the multiple polyethylenes is referred to as the second polyethylene. The second polyethylene may be a medium-density polyethylene resin (MDPE).

[0261] The second skin layer 13 preferably has a probe descent temperature of 180°C or less, from the viewpoint of improving adhesion to other layers to be laminated thereon, thereby realizing physical resistance to external impacts such as dropping.

[0262] From the viewpoint of excellent impact resistance as described above, the probe drop temperature of second skin layer 13 may be 170° C. or less, 160° C. or less, or 150° C. or less. On the other hand, from the viewpoint of printability, the probe drop temperature of second skin layer 13 may be 90° C. or more, 110° C. or more, or 130° C. or more.

[0263] The second skin layer 13 having the desired probe drop temperature can be obtained, for example, by adjusting the density, melt flow rate (MFR), stretching ratio during film formation, heat treatment / cooling conditions, etc. of the second polyethylene, or by subjecting the second skin layer 13 to treatments such as annealing or electron beam (EB) irradiation.

[0264] The density of the second polyethylene is not particularly limited, but is preferably 0.926 g / cm ３ Above, 0.930g / cm ３ Above, 0.935g / cm ３ or more, or 0.940 g / cm ３ or more, and 0.970 g / cm ３ Below, 0.965g / cm ３ or less, or 0.960 g / cm ３The second polyethylene may be a low to medium density polyethylene.

[0265] The melt flow rate MFR of the second polyethylene at 190°C under a load of 2.16 kg is not particularly limited, and may be 15 g / 10 min or less, 10 g / 10 min or less, 5 g / 10 min or less, or 3 g / 10 min or less, or may be 0.5 g / 10 min or more, 0.8 g / 10 min or more, or 1 g / 10 min or more.

[0266] The thickness of the second skin layer 13 is not particularly limited and can be appropriately determined according to the cost and application, taking into consideration the suitability of the manufacturing method and apparatus, and the suitability for lamination with other layers. From a practical standpoint, the thickness of the second skin layer 13 may be 0.3 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or 5 μm or more, or may be 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

[0267] (First Skin Layer) The first skin layer 11 may be a layer containing polyethylene. The first skin layer 11 may contain, for example, a second polyethylene, similar to the second skin layer 13. As described above, the main substrate layer 10 does not necessarily have to include the first skin layer 11, but including the first skin layer 11 tends to improve film formation stability during film production.

[0268] From the viewpoints of film formability and impact resistance, the probe drop temperature of first skin layer 11 may be 180° C. or less, 160° C. or less, or 150° C. or less. On the other hand, from the viewpoint of heat resistance, the probe drop temperature of first skin layer 11 may be 100° C. or more, 120° C. or more, or 130° C. or more.

[0269] From the viewpoints of heat resistance and film formability, first skin layer 11 may be a layer containing polypropylene. In this case, the probe drop temperature of first skin layer 11 may be 200 to 260°C.

[0270] The thickness of the first skin layer 11 is not particularly limited and can be appropriately determined according to the cost and application, taking into consideration the suitability of the manufacturing method and apparatus, and the suitability for lamination with other layers. From a practical standpoint, the thickness of the first skin layer 11 may be 0.3 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or 5 μm or more, or may be 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

[0271] The main substrate layer 10 can be produced by a known co-extrusion method such as an air-cooled inflation method, a water-cooled inflation method, or a T-die casting method. From the viewpoint of versatility, the main substrate layer 10 may be produced by either an inflation method or an air-cooled inflation method. The air-cooled inflation method is a method in which a mold with an annular lip, called a ring die (or a crosshead die), is installed at the tip of an extruder, and material is extruded into a tubular shape and continuously molded. More specifically, an air hole is installed in the center of the ring die, and compressed air is blown through the air hole to expand the tube, which is then cooled while being pulled by a roll called a pinch roll, and the film is wound up, thereby producing the laminate.

[0272] The obtained main substrate layer 10 may be subjected to a surface modification treatment to improve suitability for subsequent processes, as necessary. For example, the surface of the laminate may be modified to improve printability or lamination suitability during lamination. Examples of modification treatments include treatments that generate functional groups by oxidizing the film surface, such as corona discharge treatment, plasma treatment, and flame treatment, and wet process modification treatments that form an easy-adhesion layer by coating.

[0273] (Inorganic Oxide Layer) The inorganic oxide layer 16 contains an inorganic oxide. Examples of inorganic oxides include aluminum oxide, silicon oxide, tin oxide, magnesium oxide, and mixtures thereof. From the viewpoints of more easily maintaining gas barrier properties even after heat sterilization treatment, more excellent heat resistance, and transparency, the inorganic oxide layer 16 may contain one or more oxides selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide.

[0274] The thickness of the inorganic oxide layer 16 may be 5 to 150 nm. If the thickness of the inorganic oxide layer 16 is 5 nm or more, it is easy to form a layer with a uniform and sufficient thickness, and sufficient gas barrier properties can be achieved. If the thickness of the inorganic oxide layer 16 is 150 nm or less, flexibility can be imparted to the inorganic oxide layer 16, and even if an external load such as bending or pulling is applied to the inorganic oxide layer 16 after its formation, the occurrence of cracks in the inorganic oxide layer 16 can be suppressed. The thickness of the inorganic oxide layer 16 may be 6 nm or more, or 8 nm or more, or may be 100 nm or less, or 50 nm or less.

[0275] The inorganic oxide layer 16 can be formed by a typical vacuum deposition method. It can also be formed by other thin film formation methods such as sputtering, ion plating, plasma chemical vapor deposition (CVD), etc. The inorganic oxide layer 16 may be formed by vacuum deposition from the viewpoint of excellent productivity.

[0276] The heating means for the vacuum deposition method can be any of electron beam heating, resistance heating, and induction heating. The vacuum deposition method may be electron beam heating in view of the wide range of evaporation material options. In view of improving the adhesion between the main substrate layer 10 (here, for example, the second skin layer 13) and the inorganic oxide layer 6 and the density of the inorganic oxide layer 16, deposition may be performed by a plasma-assisted method, an ion-beam-assisted method, or the like. In view of improving the transparency of the inorganic oxide layer 16, deposition may be performed by reactive deposition.

[0277] (Gas Barrier Coating Layer) The gas barrier coating layer 17 is a layer provided on the inorganic oxide layer 16 for the purposes of protecting the inorganic oxide layer 16 and complementing the gas barrier property.

[0278] The gas barrier coating layer 17 may be a heat-cured product of a composition containing at least one of a water-soluble polymer and a hydrolyzate thereof, and one or more selected from the group consisting of a metal alkoxide, a silane coupling agent, and a hydrolyzate thereof.

[0279] Examples of the water-soluble polymer include hydroxyl group-containing polymer compounds such as polyvinyl alcohol, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. The water-soluble polymer may be polyvinyl alcohol (PVA) from the viewpoint of excellent gas barrier properties.

[0280] Examples of metal alkoxides include compounds represented by the following general formula: M(OR １１ ) ｍ (R １２ ) ｎ－ｍ ... (1) In the above formula (1), R １１ and R １２ are each independently a monovalent organic group having 1 to 8 carbon atoms. １１ and R １２ may each independently be an alkyl group such as a methyl group or an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. １１ and R １２ If there are multiple R １１ Doshi or R １２ They may be the same or different.

[0281] The metal alkoxides include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(O-2'-C ３ H ７ ) ３ The metal alkoxide may be tetraethoxysilane or triisopropoxyaluminum, which are relatively stable in aqueous solvents after hydrolysis.

[0282] Examples of the silane coupling agent include compounds represented by the following general formula: Si(OR ２１ ) ｐ (R ２２ ) ３－ｐ R ２３ ... (2) In the above formula (2), R ２１ represents an alkyl group such as a methyl group or an ethyl group, and R２２ represents a monovalent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloxy group, or an alkyl group substituted with a methacryloxy group, and R ２３ represents a monovalent organic functional group, and p represents an integer of 1 to 3. ２１ or R ２２ If there are multiple R ２１ Doshi or R ２２ R may be the same or different. ２３ Examples of the monovalent organic functional group represented by the formula (I) include a monovalent organic functional group containing a glycidyloxy group, an epoxy group, a mercapto group, a hydroxyl group, an amino group, an alkyl group substituted with a halogen atom, and an isocyanate group.

[0283] Examples of the silane coupling agent include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and 3-isocyanate alkylalkoxysilane.

[0284] The silane coupling agent may be a polymer such as a dimer or trimer of the above-mentioned silane coupling agent. A preferred polymer is a trimer, such as 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate, which is a condensation polymer of 3-isocyanatoalkylalkoxysilane. Adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a water-soluble polymer can improve the water resistance of the gas barrier coating layer through hydrogen bonding.

[0285] The gas barrier coating layer 17 can be formed using a composition (hereinafter referred to as an overcoat agent) obtained by adding a water-soluble polymer and a metal alkoxide and / or a silane coupling agent to water or a water / alcohol mixture. The overcoat agent can be prepared, for example, by mixing a solution of a hydroxyl-containing polymer compound, which is a water-soluble polymer, in an aqueous solvent (water or a water / alcohol mixture) with a metal alkoxide and / or a silane coupling agent, either directly or after being previously treated by hydrolysis or the like. Additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, and a colorant may also be added to the overcoat agent.

[0286] The gas barrier coating layer 17 may be a coating (polycarboxylic acid polyvalent metal salt coating) containing a polycarboxylic acid polyvalent metal salt, which is a reaction product between a carboxy group of a polycarboxylic acid polymer and a polyvalent metal compound. The polycarboxylic acid polyvalent metal salt coating can be formed by applying a mixed solution of a polycarboxylic acid polymer and a polyvalent metal compound to the surface of the inorganic oxide layer 16 (or, if the inorganic oxide layer 16 is not present, the main substrate layer 10 (here, for example, the second skin layer 13)) and heating and drying. Alternatively, a coating liquid containing a polycarboxylic acid polymer as a main component may be applied to the surface of the inorganic oxide layer 16 (or, if the inorganic oxide layer 16 is not present, the main substrate layer 10 (here, for example, the second skin layer 13)) and dried to form a coating, and then a coating liquid containing a polyvalent metal compound as a main component may be applied to the coating and dried to form a coating, and a crosslinking reaction between these coatings may be caused to form the polycarboxylic acid polyvalent metal salt coating.

[0287] The polycarboxylic acid polymer is a polymer having two or more carboxyl groups in the molecule. Examples of the polycarboxylic acid polymer include polymers of ethylenically unsaturated carboxylic acids, copolymers of ethylenically unsaturated carboxylic acids with other ethylenically unsaturated monomers, and acidic polysaccharides having carboxyl groups in the molecule, such as alginic acid, carboxymethylcellulose, and pectin.

[0288] Examples of ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of ethylenically unsaturated monomers copolymerizable with ethylenically unsaturated carboxylic acids include saturated carboxylic acid vinyl esters such as ethylene, propylene, and vinyl acetate, alkyl acrylates, alkyl methacrylates, alkyl itaconates, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. One or more types of polycarboxylic acid polymers may be used.

[0289] From the viewpoint of excellent gas barrier properties, the ethylenically unsaturated carboxylic acid polymer is preferably a polymer containing structural units derived from one or more monomers selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid, and more preferably a polymer containing structural units derived from one or more monomers selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid.

[0290] In the polymer of ethylenically unsaturated carboxylic acid, the proportion of structural units derived from one or more monomers selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 80 mol % or more, and more preferably 90 mol % or more, based on the total amount of monomers in the polymer.

[0291] The number-average molecular weight of the polycarboxylic acid polymer is preferably 2,000 to 10,000,000, and more preferably 5,000 to 1,000,000. When the number-average molecular weight is 2,000 or more, the gas barrier coating layer 17 has sufficient water resistance, and deterioration of gas barrier properties and transparency and whitening due to moisture can be suppressed. When the number-average molecular weight is 10,000,000 or less, the viscosity of the coating liquid when forming the gas barrier coating layer 17 does not become too high, making it easier to form a coating.

[0292] The amount of metal alkoxide in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per 1 part by mass of the water-soluble polymer, from the viewpoint of maintaining adhesion to the inorganic oxide layer 16 and gas barrier properties. Similarly, the amount of silane coupling agent can be 0.01 to 1 part by mass, or may be 0.1 to 0.5 parts by mass, per 1 part by mass of the water-soluble polymer. When a silane compound (alkoxysilane) is used as the metal alkoxide, the amount of the silane compound (metal alkoxide and silane coupling agent) in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per 1 part by mass of the water-soluble polymer.

[0293] The overcoating agent can be applied onto the inorganic oxide layer 16 by, for example, dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, etc. The coating film obtained by applying the overcoating agent can be dried by, for example, hot air drying, heat roll drying, high frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0294] The temperature at which the coating film is dried can be, for example, 50 to 150° C., and preferably 70 to 100° C. By keeping the drying temperature within the above range, the occurrence of cracks in the inorganic oxide layer 16 and the gas barrier coating layer 17 can be further suppressed, and excellent barrier properties can be achieved.

[0295] The gas barrier coating layer 17 may be formed using an overcoat agent containing a water-soluble polymer (e.g., polyvinyl alcohol-based resin) and a silane compound. The overcoat agent may contain an acid catalyst, an alkali catalyst, a photopolymerization initiator, or the like, as needed. Examples of the silane compound include silane coupling agents, polysilazanes, and siloxanes. Specific examples include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane.

[0296] The gas barrier coating layer 17 described above can maintain excellent gas barrier properties even after heat sterilization. Therefore, when the printed matter 108 is used as a packaging material for heat sterilization, the packaging material has excellent adhesion even after heat sterilization. Furthermore, the gas barrier coating layer 17 described above is preferable because it has sufficient transparency, flex resistance, and stretch resistance, and there is no risk of generating harmful substances such as dioxins.

[0297] The thickness of the gas barrier coating layer 17 may be 0.05 μm or more, or 0.1 μm or more, from the viewpoint of excellent gas barrier properties. The thickness of the gas barrier coating layer 17 may be 1 μm or less, or 0.5 μm or less, from the viewpoints of easily forming a uniform coated surface, reducing the load due to drying, flexibility, and production costs.

[0298] (Anchor Coat Layer) From the viewpoint of improving the adhesion between the main substrate layer 10 (here, for example, the second skin layer 13) and the inorganic oxide layer 16, an anchor coat layer may be provided between the main substrate layer 10 (here, for example, the second skin layer 13) and the inorganic oxide layer 16.

[0299] The anchor coat layer can be formed from a coating liquid containing a resin such as an acrylic resin, an epoxy resin, an acrylic urethane resin, a polyester polyurethane resin, a polyether polyurethane resin, etc. From the viewpoints of heat resistance and interlayer adhesive strength, the anchor coat layer may be formed from a coating liquid containing an acrylic urethane resin or a polyester polyurethane resin.

[0300] The method for applying the coating liquid that forms the anchor coat layer may be a known coating method, and examples thereof include immersion (dipping), spraying, methods using a coater, a printer, a brush, etc. In addition, examples of the types of coaters and printers used in these methods and the coating methods thereof include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coaters, microgravure coaters, coaters with chamber doctor, air knife coaters, dip coaters, bar coaters, comma coaters, and die coaters.

[0301] The method for drying the anchor coat layer is not particularly limited, but examples thereof include natural drying, drying in an oven set at a predetermined temperature, and using a dryer attached to a coater, such as an arch dryer, floating dryer, drum dryer, infrared dryer, etc. Drying conditions can be appropriately selected depending on the drying method, and for example, in a method of drying in an oven, drying may be performed at 60 to 100°C for about 1 second to 2 minutes.

[0302] The thickness of the anchor coat layer may be 0.01 μm or more, 0.03 μm or more, or 0.05 μm or more from the viewpoint of easily obtaining sufficient adhesion between layers, and may be 5 μm or less, 3 μm or less, or 2 μm or less from the viewpoint of excellent gas barrier properties.

[0303] In order to improve the adhesion between the base material layer 1 and the ink layer 4, the surface of the layer in the base material layer 1 that comes into contact with the ink layer 4 may be subjected to pretreatment such as corona treatment, plasma treatment, or flame treatment, or a coating layer such as an easy-adhesion layer may be provided.

[0304] In particular, by subjecting the surface of the base layer 1 on the ink layer 4 side to plasma treatment or corona treatment, the wettability of the surface changes, and this change in wettability causes hydroxyl groups (OH groups) of compounds present on the surface to rise from the surface, thereby improving the adhesion between the base layer 1 and the ink layer 4. Furthermore, by laminating an anchor coat layer on the surface of the gas barrier coating layer 17 of the base layer 1 as described above, the adhesion between the base layer 1 and the ink layer 4 can be improved.

[0305] <Modified Layer> Examples of the ink modifier for the modified layer 3 include ester-based modifiers, ether-based modifiers, and urethane-based modifiers, which may be one-component curing types or two-component curing types.

[0306] The ink modifier preferably has gas barrier properties from the viewpoint of excellent gas barrier properties. Even if minute cracks occur in the inorganic oxide layer 16 or the gas barrier coating layer 17, the gas barrier modifier can fill in the cracks and fill in the gaps, thereby preventing a decrease in the gas barrier properties of the printed matter 108.

[0307] A gas barrier ink modifier is a modifier that can exhibit gas barrier properties after curing. Examples of gas barrier ink modifiers include epoxy adhesives, polyester / polyurethane adhesives, etc. Specific examples of gas barrier ink modifiers include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0308] The oxygen permeability of the gas barrier ink modifier is, for example, 150 cc / m ２ ·day·atm or less, and 100cc / m ２ ·day·atm or less is more preferable, and 80cc / m ２ It is more preferable that the viscosity is 50 cc / m or less. ２ It is particularly preferable that the oxygen permeability is equal to or less than 1 / 4 day / atm. When the oxygen permeability is within the above range, the gas barrier properties of the printed matter 108 can be sufficiently improved.

[0309] The ink modifier can be formed using a solvent-based ink modifier (an ink modifier containing an organic solvent) or a solventless ink modifier (an ink modifier not containing an organic solvent). These ink modifiers may be either one-component curing or two-component curing. Examples of these ink modifiers include urethane-based ink modifiers, epoxy-based ink modifiers, and silicone-based ink modifiers. From the viewpoint of impact resistance, urethane-based ink modifiers are preferred, and two-component curing urethane-based ink modifiers are particularly preferred. Furthermore, from the viewpoint of improving oxygen barrier properties, gas barrier ink modifiers are preferred, and examples of such ink modifiers include solvent-based epoxy-based ink modifiers. From the viewpoint of reducing environmental impact, solventless ink modifiers can be used.

[0310] The polyol component may be one or a mixture of two or more selected from the group consisting of polyester polyols, polyether polyols, polyether ester polyols, and polyurethane polyols.

[0311] The polyester polyol may be, for example, an ester reaction product of a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a glycol-based solvent. The polycarboxylic acid may be, for example, succinic acid, glutaric acid, isophthalic acid, terephthalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, or dimer acid. The glycol-based solvent may be, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, or 1,6-hexanediol.

[0312] The polyether polyol may be, for example, a polymer of an oxirane compound and a low-molecular-weight polyol. The oxirane compound may be, for example, ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran. The low-molecular-weight polyol may be, for example, water, ethylene glycol, propylene glycol, trimethylolpropane, or glycerin.

[0313] The polyetherester polyol may be obtained by reacting, for example, a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a polyether polyol.

[0314] The polyurethane polyol may be, for example, the reaction product of a polyester polyol, a polyether polyol, or a polyetherester polyol with a polyisocyanate monomer.

[0315] The polyisocyanate component may be an aliphatic polyisocyanate, an aromatic polyisocyanate, or a mixture thereof.

[0316] The aliphatic polyisocyanate may be, for example, a polyisocyanate monomer, a polyisocyanate derivative, or a polyisocyanate-terminated prepolymer. The polyisocyanate monomer may be, for example, tetramethylene diisocyanate, isopropylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, or trimethylhexamethylene diisocyanate. The polyisocyanate derivative may be, for example, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, lysine diisocyanate, or isophorone diisocyanate.

[0317] The aromatic polyisocyanate may be, for example, a polyisocyanate monomer, a polyisocyanate derivative, or a polyisocyanate-terminated prepolymer. The polyisocyanate monomer may be, for example, tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, or tetramethylxylylene diisocyanate. The polyisocyanate derivative may be, for example, an isocyanurate derived from the polyisocyanate monomer. The polyisocyanate-terminated prepolymer may be a bifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a bifunctional polyol compound such as polypropylene glycol. The polyisocyanate-terminated prepolymer may also be a multifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a trifunctional or higher polyol compound such as trimethylolpropane.

[0318] Although the adhesive components are similar, solvent-based ink modifiers generally have higher molecular weights than solventless ink modifiers, so solvent-based ink modifiers have superior initial adhesion immediately after lamination and adhesion strength after aging and curing. Furthermore, solvent-based ink modifiers have excellent resistance to the contents, so they have the advantage of being less likely to lose adhesive strength after the contents are stored.

[0319] The ink modifier can be formed by applying the ink modifier to the ink layer 4 by, for example, a bar coating method, a dipping method, a roll coating method, a gravure coating method, a reverse coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, a spray coating method, a gravure offset method, or the like to form a coating film, and then drying and curing the coating film.

[0320] When a solvent-based ink modifier is used as the ink modifier, a laminated film can be obtained by applying a solvent-based adhesive onto the ink layer 4 using a general dry lamination method, laminating it with the sealant layer 2, and then thermally drying to remove the solvent. Thermal drying can be carried out using an oven or the like under conditions of, for example, a temperature of 50 to 80°C, an oven length of 5 to 20 m, and a processing speed of 50 to 200 m / min.

[0321] When a solventless ink modifier is used as the ink modifier, a laminated film can be obtained by applying the solventless ink modifier onto the ink layer 4 and bonding it to the sealant layer 2 using the method described above.

[0322] When the solventless ink modifier is, for example, a two-component curing urethane-based ink modifier, a base agent containing a polyol component and a curing agent containing a polyisocyanate component are typically supplied separately and mixed before reaching the coating section of the laminating device. The mixed ink modifier is supplied, for example, between a doctor roll and a metering roll, which rotate in opposite directions in the laminating device. The supplied ink modifier is transferred from the metering roll to a coating roll and coated on the surface of the ink layer 4 printed on the substrate layer 1 supplied between the coating roll and the impression roll.

[0323] The ink layer 4 coated with the ink modifier and the substrate layer 1 are laminated with the sealant layer 2 and taken up by a winder to obtain a printed matter 108. The obtained printed matter 108 is preferably aged at 20 to 50° C. for 24 to 96 hours. The doctor roll, metering roll, and coating roll described above are examples of the configuration of a laminating device, and the configuration may differ depending on the laminating device used.

[0324] Here, in order to make the viscosity of the solvent-free ink modifier low enough to be able to apply it without a solvent, it is preferable to heat a metal roll such as a doctor roll or a coating roll to melt the solvent-free ink modifier and reduce the viscosity before applying and laminating.

[0325] Therefore, it is preferable to set the heating temperature of the solventless ink modifier within the range of 50 to 100°C. Furthermore, the heating temperature is preferably set within the range of 50 to 100°C so that the viscosity of the solventless adhesive at that heating temperature is 200 to 2000 mPa·s. From the viewpoint of obtaining a printed matter 108 having a more uniform coating appearance, the heating temperature is more preferably a temperature at which the viscosity of the solventless ink modifier is 300 to 1500 mPa·s, and even more preferably a temperature at which the viscosity is 500 to 1000 mPa·s. Furthermore, from the viewpoint of further improving the lamination strength of the printed matter 108 and further suppressing the expansion and contraction of the base material layer 1, the heating temperature is more preferably 50 to 90°C, and even more preferably 50 to 80°C.

[0326] Because a solventless ink modifier is used in bonding the base layer 1 on which the ink layer 4 is formed and the sealant layer 2, long-term thermal drying (oven drying, etc.) at high temperatures to remove the solvent is not required. This makes it possible to suppress expansion and contraction of the base layer 1, and to obtain a printed matter 108 in which the image on the ink layer 4 has good dimensional stability.

[0327] When a solvent-based ink modifier is used, the temperature at which the coating film is dried may be, for example, 30 to 200° C., and preferably 50 to 180° C. The temperature at which the coating film is cured may be, for example, 20 to 70° C., and preferably 30 to 60° C. By keeping the drying and curing temperatures within the above ranges, it is possible to suppress the occurrence of cracks in the ink layer 4 and the modified layer 3, and it is possible to sufficiently improve the gas barrier properties of the printed matter 108.

[0328] The thickness of the modified layer 3 is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm. When the thickness of the modified layer 3 is 0.1 μm or more, cushioning properties that absorb external impacts can be obtained, making it easier to prevent the inorganic oxide layer 16 from cracking and further improving the gas barrier properties of the printed matter 108. When the thickness of the modified layer 3 is 20 μm or less, the flexibility of the printed matter 108 tends to be sufficiently maintained.

[0329] <Sealant Layer> The sealant layer 2 is a layer made of, for example, polyethylene. The sealant layer 2 is a layer that is bonded by heat sealing when forming a packaging material such as a packaging bag using the printed matter 108. The polyethylene that makes up the sealant layer 2 may be low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very low-density polyethylene (VLDPE) from the viewpoint of excellent heat sealing properties. From the viewpoint of environmental impact, the sealant layer 2 may be made of a biomass-derived polyethylene resin or a recycled polyethylene resin. The sealant layer 2 may be made of, for example, a non-oriented polyethylene film.

[0330] Low density polyethylene has a density of 0.900 g / cm ３ 0.925g / cm or more ３ As the linear low density polyethylene, polyethylene having a density of 0.900 g / cm3 or less can be used. ３ 0.925g / cm or more ３ As the ultra-low density polyethylene, polyethylene having a density of 0.900 g / cm3 or less can be used. ３ Less than 100% polyethylene can be used.

[0331] The sealant layer 2 may contain a resin other than polyethylene. Examples of resins other than polyethylene include olefin-based resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, ethylene-(meth)acrylic acid copolymer, homopolypropylene (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α-olefin copolymer, and polybutene. The sealant layer 2 may contain additives such as antioxidants, lubricants, antiblocking agents, and antistatic agents.

[0332] The thickness of the sealant layer 2 may be, for example, 20 μm or more, 40 μm or more, or 50 μm or more. When the thickness of the sealant layer 2 is 20 μm or more, sufficient heat seal strength can be achieved. The thickness of the sealant layer 2 may be, for example, 200 μm or less, 170 μm or less, or 150 μm or less. When the thickness of the sealant layer 2 is 200 μm or less, excellent processability can be achieved.

[0333] The sealant layer 2 may contain a polyolefin resin or a composition containing a polyolefin resin and a white pigment (a milky white polyolefin resin composition). The sealant layer 2 is a layer for heat sealing when the printed matter 108 is made into a packaging bag or the like, and has thermal adhesive properties.

[0334] Examples of polyolefin resins include ethylene resins, polypropylene resins, propylene resins, ethylene-propylene copolymers, ethylene-α,β-unsaturated carboxylic acid copolymers, esters of ethylene-α,β-unsaturated carboxylic acid copolymers, acid anhydride-modified polyolefins, and blends of two or more of these. Among these, polypropylene resins (particularly CPP: unstretched polypropylene resin) are particularly preferred because they have excellent thermal adhesiveness, heat resistance, and oil resistance.

[0335] Examples of ethylene-based resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and ethylene-α-olefin copolymers.

[0336] Examples of polypropylene resins include homopolypropylene, block polypropylene, and random polypropylene.

[0337] Examples of the propylene-based resin include propylene-α-olefin copolymers.

[0338] Examples of the ethylene-α,β-unsaturated carboxylic acid copolymer include an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer.

[0339] Examples of acid anhydride-modified polyolefins include ethylene-maleic anhydride graft copolymers and terpolymers such as ethylene-ethyl acrylate-maleic anhydride.

[0340] Examples of materials constituting the white pigment include inorganic oxides such as titanium oxide, alumina, mica, lead oxide (white lead), zinc oxide, calcium carbonate, barium carbonate, barium sulfate, kaolin, potassium titanate, talc, magnesium hydroxide, natural silicic acid, and synthetic silicic acid (white carbon). Among these, pigments containing titanium oxide are preferably used from the viewpoints of hiding power and dispersibility upon addition. Titanium oxide may be of the rutile type or the anatase type. The surface of the pigment containing titanium oxide may be treated with a metal oxide such as aluminum (Al) or silica (Si). The average particle size of the white pigment can be selected within a range that does not interfere with the object of the present invention.

[0341] When the sealant layer 2 contains a white pigment, the content of the polyolefin resin may be 90% by mass or more, 92% by mass or more, or 94% by mass or more, based on the total mass of the sealant layer 2 (total mass of the milky-white polyolefin resin composition), from the viewpoint of thermal adhesion. From the viewpoints of light-blocking and concealing properties, the content of the polyolefin resin may be 97% by mass or less, 96% by mass or less, or 95% by mass or less, based on the total mass of the sealant layer 2. From these viewpoints, the content of the polyolefin resin may be 90 to 97% by mass, based on the total mass of the sealant layer 2.

[0342] When the sealant layer 2 contains a white pigment, the content of the white pigment may be 3% by mass or more, 4% by mass or more, or 5% by mass or more, based on the total mass of the sealant layer 2 (total mass of the milky-white polyolefin resin composition), from the viewpoint of light-blocking properties and concealing properties. From the viewpoint of thermal adhesiveness, the content of the white pigment may be 10% by mass or less, 8% by mass or less, or 6% by mass or less, based on the total mass of the sealant layer 2. From these viewpoints, the content of the white pigment may be 3 to 10% by mass, based on the total mass of the sealant layer 2.

[0343] The ratio of the content of the white pigment to the content of the polyolefin resin (pigment / resin ratio) may be 0.04 to 0.1, 0.04 to 0.08, or 0.05 to 0.06, in mass ratio.

[0344] The sealant layer 2 may contain other additives as needed, such as antioxidants, slip agents, antiblocking agents, and weather resistance agents.

[0345] The sealant layer 2 may have a single-layer structure or a multi-layer structure. When the sealant layer 2 contains a white pigment and has a multi-layer structure, all of the constituent layers may be layers containing a polyolefin-based resin, and for example, at least one of the layers may be a layer containing a milky-white polyolefin-based resin composition. In this case, it is preferable that the layer containing the milky-white polyolefin-based resin composition is located on the ink layer 4 side. Furthermore, for example, when the sealant layer 2 has a three-layer structure consisting of an outer layer / an intermediate layer / an outer layer, it is preferable that the intermediate layer is a layer containing a milky-white polyolefin-based resin composition. The polyolefin-based resins used in each layer may be the same or different.

[0346] When a white pigment is contained, the thickness of the sealant layer 2 is not particularly limited and can be set appropriately depending on the desired properties. In this case, the thickness of the sealant layer 2 may be, for example, 15 to 200 μm, 30 to 200 μm, or 50 to 200 μm. By increasing the thickness of the sealant layer 2, sufficient hiding power and light-blocking properties can be ensured while keeping the concentration of the white pigment low.

[0347] As described above, the sealant layer 2 may be a layer composed of one or more types of sealant films. The sealant film may be, for example, a non-stretched resin film. The method for forming the sealant film is not particularly limited, and known methods such as melt molding methods such as inflation and T-die extrusion are preferably used.

[0348] When the sealant layer 2 contains a white pigment, a masterbatch in which the white pigment is pre-kneaded into a polyolefin resin may be used when forming the sealant film. The concentration of the white pigment in the masterbatch may be, for example, about 40 to 70 mass %. When using a masterbatch, the masterbatch and polyolefin resin may be kneaded together to obtain a desired blend ratio.

[0349] <Protective Layer> In this embodiment, a heat-resistant layer is used as the protective layer 6. The heat-resistant layer is provided to prevent defects during heat sealing during bag production and filling / sealing, and to ensure heat-sealing suitability. Specifically, it can prevent appearance defects such as wrinkles when the base material layer 1 comes into contact with the heat seal bar, and the base material layer 1 from adhering (being removed) to the heat seal bar due to thermal welding. Furthermore, when the printed matter 108 is used in a packaging bag having a standing pouch shape, it can prevent the base material layers 1 from thermally welding to each other when the base material portions are placed face to face with each other and bottom-sealed. For this purpose, the heat-resistant layer is provided as the outermost layer of the printed matter 108.

[0350] The thickness of the heat-resistant layer is adjusted according to the total thickness of the printed matter 108, but from the viewpoint of improving heat resistance and reducing the amount of heat required for heat sealing, it may be, for example, 0.1 to 5.0 μm, 0.2 to 4.0 μm, or 0.3 to 2.0 μm.

[0351] The heat-resistant layer provided on the outer surface of the base material layer 1 must be heat-resistant enough to not soften, melt, or decompose even when heated to, for example, 140°C during heat sealing. Therefore, the heat-resistant layer preferably contains a thermosetting resin or a resin with a melting point of 160°C or higher. The resin is preferably one or more resins selected from the group consisting of polyacrylic, polyurethane, polyester, polyamide, polyamideimide, vinyl chloride-vinyl acetate copolymer, and epoxy. Among these, acrylic resins, urethane resins, vinyl chloride-vinyl acetate copolymers, polyester resins, and mixtures thereof are more preferred.

[0352] In order to form a urethane bond, a two-component curing resin is preferred, and the curing agent is not particularly limited as long as it can react with the two-component curing resin and cure it, but polyvalent isocyanate compounds are preferred, and examples thereof include aromatic diisocyanate compounds such as tolylene diisocyanate and 4,4-diphenylmethane diisocyanate, aliphatic diisocyanate compounds such as xylylene diisocyanate and hexamethylene diisocyanate, polymers thereof, and derivatives thereof.

[0353] The heat-resistant layer may contain a matting agent component. By containing the matting agent component in the heat-resistant layer, it is possible to improve heat resistance and adjust slip properties. Examples of the matting agent component include inorganic particles. Examples of inorganic particles include silica, talc, calcium carbonate, precipitated barium sulfate, alumina, acid clay, clay, magnesium carbonate, carbon black, tin oxide, titanium white, mica, and glass.

[0354] The heat-resistant layer may contain a wax such as polyethylene wax, polypropylene wax, polytetrafluoroethylene wax, montan wax, paraffin wax, microcrystalline wax, amide wax, petroleum wax, or a lubricant such as liquid paraffin, white petrolatum, castor oil, etc. By containing a lubricant in the heat-resistant layer, it is possible to impart appropriate slipperiness to the printed matter 108 when dried, thereby improving the production efficiency of the packaging material.

[0355] The heat-resistant layer can be formed by applying a coating liquid for the heat-resistant layer. The coating amount of the coating liquid for the heat-resistant layer after drying is 0.1 to 5 g / m ２ It is preferable that the density is 0.3 to 3 g / m ２ If the coating amount is within the above range, the amount of residual solvent is small, and blocking during film formation can be suppressed.

[0356] The method for applying the coating liquid for the heat-resistant layer is not particularly limited, and coating methods such as roll coating, gravure coating, knife coating, dip coating, and spray coating can be used.

[0357] Suitable examples of the solvent include alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; glycol-based solvents such as 2-butoxyethanol and propylene glycol monomethyl ether; and hydrocarbon-based solvents such as toluene, xylene, n-hexane, and methylcyclohexane.

[0358] When the heat-resistant layer is formed by applying and drying (curing) the coating liquid for the heat-resistant layer, an adhesion-imparting layer may be formed on the base material layer 1 in order to improve the adhesion between the base material layer 1 and the heat-resistant layer, as long as the recyclability is not impaired.

[0359] The printed matter 108 may contain 90% by mass or more of the same type of resin (polyethylene). In this case, the printed matter 108 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 108 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0360] As described above, the printed matter 108 of this embodiment has the same effects as the printed matter 104 of the fourth embodiment. In addition, the printed matter 108 also has the barrier properties attributable to the base material layer 1.

[0361] Here, when recycling a printed matter such as printed matter 108, there is a risk that the ink in the ink layer will penetrate into the modified layer. Typically, after dissolving the layer laminated on the base layer with a solvent to leave only the base layer, the components dissolved in the solvent must be decolorized (deinked). However, if the ink penetrates into the transparent modified layer, it will be treated as a recycled resin, which is disadvantageous for recycling. Therefore, it is desirable that the ink does not penetrate into the modified layer. In this regard, in the present invention, the ink layer 4 is instantly cured by irradiation with active energy rays, and excessive penetration of the ink into the modified layer (penetration far exceeding the amount of penetration required to improve adhesion) is suppressed, thereby improving recyclability and making it possible to omit the deinking process. In the present invention, the adhesion between the substrate layer 1 and the ink layer 4 is increased by irradiation with active energy rays. However, from the viewpoint of improving recyclability (peeling the ink layer 4 from the substrate layer 1), it is also preferable that the adhesion between the substrate layer 1 and the ink layer 4 is not excessively high, and it is also a preferred embodiment that the irradiation dose of the active energy rays is 100 kGy or less.

[0362] <Uses> The printed matter 108 can be used for the same purposes as the printed matter 104 of the fourth embodiment. The printed matter 108 can also be used as packaging material for forming packaging bags and the like. Specifically, it can be used as packaging material for flat bags, three-sided bags, two-sided bags, gusseted bags, standing pouches, pouches with spouts, pouches with beaks, and the like. Packaging material bags made from the printed matter 108 can be said to be packaging material that is highly recyclable, has no distortion (little distortion) of the pattern, and is highly impact resistant.

[0363] In the printed matter 108, the ink layer 4 is provided in a position that is visible from the outside of the printed matter 108 for the purpose of displaying information about the contents, identifying the contents, or improving the design of the packaging bag.

[0364] Furthermore, in this embodiment, the case where the main component of the base material layer 1 is polyethylene has been described, but the present invention can also be applied to cases where the main component of the base material layer 1 is other polyolefins, nylon, or the like.

[0365] [Ninth embodiment] Figure 10 is a cross-sectional view schematically showing the layer structure of a printed matter according to a ninth embodiment of the present invention. The printed matter 109 shown in Figure 10 is a laminate formed by reverse offset printing. The printed matter 109 comprises, from the top (surface side), a protective layer 6, a substrate layer 1, an ink layer 4, a modified layer 3, a barrier layer 5, an adhesive layer 7, and a sealant layer 2, in this order.

[0366] The printed matter 109 has a configuration in which the substrate layer 1 includes only the main substrate layer 10, and has the same configuration as the printed matter 108, except that it further includes a barrier layer 5 and an adhesive layer 7. Like the printed matter 108, the printed matter 109 has a configuration that is particularly preferable for achieving mono-materialization. The ink layer 4, modified layer 3, and sealant layer 2 included in the printed matter 109 have the same configurations as those described in the eighth embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the eighth embodiment.

[0367] <Substrate Layer> The substrate layer 1 includes a main substrate layer 10 similar to that of the printed matter 108. The configuration of the main substrate layer 10 is the same as that of the eighth embodiment, and therefore detailed description thereof will be omitted. Note that the substrate layer 1 may also include an inorganic oxide layer 16, a gas barrier coating layer 17, and the like similar to those of the eighth embodiment.

[0368] <Barrier Layer> The barrier layer 5 has a gas barrier layer 52 and a barrier substrate layer 51, in this order from the modified layer 3 side. The barrier substrate layer 51 has a configuration similar to that of the main substrate layer 10 in the substrate layer 1 of the printed matter 108. Specifically, the barrier substrate layer 51 has a first skin layer 511, a core layer 512, and a second skin layer 513 that are similar to the first skin layer 11, the core layer 12, and the second skin layer 13, respectively, of the main substrate layer 10. The gas barrier layer 52 has an anchor coat layer 521 and an inorganic oxide layer 522 that are similar to the anchor coat layer and the inorganic oxide layer 16, respectively, in the substrate layer 1 of the printed matter 108. In the barrier layer 5, the first skin layer 511, the core layer 512, the second skin layer 513, the anchor coat layer 521, and the inorganic oxide layer 522 are laminated in this order. The gas barrier layer 52 may also have a gas barrier coating layer similar to the gas barrier coating layer of the base material layer 1 in the printed matter 108. Therefore, a detailed description of the barrier layer 5 will be omitted.

[0369] <Adhesive Layer> The adhesive layer 7 may be the same as the adhesive layer 7 of the printed matter 103 of the third embodiment. The adhesive layer 7 is preferably a layer formed from a gas barrier adhesive.

[0370] The printed matter 109 may contain 90% by mass or more of the same type of resin (polyethylene). In this case, the printed matter 109 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 109 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0371] As described above, the printed matter 109 of this embodiment has the same effects as the printed matter 104 of the fourth embodiment. In addition, the printed matter 109 also has the barrier properties due to the barrier layer 5.

[0372] <Use> The printed matter 109 can be used for the same purpose as the printed matter 108 of the eighth embodiment.

[0373] [Tenth embodiment] Fig. 11 is a cross-sectional view schematically showing the layer structure of a printed matter according to a tenth embodiment of the present invention. The printed matter 110 shown in Fig. 11 is a laminate formed by reverse offset printing. The printed matter 110 comprises, from the top (surface side), a protective layer 6, a base material layer 1, an ink layer 4, a modified layer 3, and a sealant layer 2, in this order.

[0374] The printed matter 110 has the same configuration as that described in the eighth embodiment, except that the configuration of the base material layer 1 and the sealant layer 2 has been changed, and the printing method and the method of irradiating active energy rays can be the same as those in the eighth embodiment.

[0375] <Substrate Layer> [Polypropylene Film] The substrate layer 1 comprises a main substrate layer 10 having three layers, each containing polypropylene, in this order: a first skin layer 121 on the side opposite the sealant layer 2, a core layer 122, and a second skin layer 123 on the sealant layer 2 side; and an anchor coat layer 126, a vapor deposition layer 127, and a gas barrier coating layer 128, following the second skin layer 123 of the main substrate layer 10, in this order. The main substrate layer 10 does not necessarily have to include the second skin layer 123. The first skin layer 121 and the second skin layer 123 can each be the outermost layer of the main substrate layer 10. The main substrate layer 10 is a multilayer film that can be obtained by coextrusion, and can therefore also be called a coextruded multilayer film.

[0376] The core layer 122 contains polypropylene. The first skin layer 121 contains a copolymer of propylene and another monomer. The printed matter 110 having the main substrate layer 10 can be used in packaging that is subjected to heat sterilization. When the surface of the first skin layer 121 is subjected to elemental quantitative analysis by X-ray photoelectron spectroscopy, it is preferable that the average ratio of the number of oxygen atoms to the number of carbon atoms (hereinafter simply referred to as "O / C") is 0.010 to 0.050 and the standard deviation of O / C is 0.0010 to 0.0050.

[0377] The main substrate layer 10 exhibits excellent adhesion to other layers after heat sterilization, excellent adhesion stability, and is less likely to reduce the wettability of other layers. The inventors believe the reason for this effect is as follows: Polypropylene films are typically composed of carbon and hydrogen atoms, resulting in low wettability and poor adhesion to other layers. When the average O / C value is less than 0.01, the polypropylene film exhibits low wettability and insufficient adhesion. When the average O / C value is greater than 0.05, as described below, when a polypropylene film is used as the substrate anchor coating layer 126, the components on the surface of the polypropylene film migrate to another layer (the vapor deposition layer 127), reducing the wettability of the vapor deposition layer 127. Forming a gas barrier coating layer 128 on a vapor deposition layer 127 with reduced wettability reduces the coatability of the gas barrier coating layer 128, leading to reduced gas barrier properties. The surface of the first skin layer 121 of the main substrate layer 10 preferably has an average O / C ratio of 0.01 to 0.05 and a standard deviation of O / C of 0.0010 to 0.0050. Furthermore, the first skin layer 121 preferably contains a copolymer of propylene and another monomer. This allows the main substrate layer 10 to have excellent adhesion to other layers after heat sterilization treatment, excellent adhesion stability, and is less likely to reduce the wettability of other layers.

[0378] The main substrate layer 10 is a film containing polypropylene. The main substrate layer 10 may be, for example, a film obtained by forming polypropylene into a sheet, stretching it, and oriented it uniaxially or biaxially.

[0379] The polypropylene may be crystalline polypropylene. From the viewpoint of improving heat resistance, the polypropylene may be homopolypropylene, which is a homopolymer of propylene. The polypropylene may contain, for example, a random copolymer of propylene and an α-olefin.

[0380] The polypropylene content may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the main base material layer 10. The polypropylene content may be substantially 100% by mass, based on the total mass of the main base material layer 10 (an embodiment in which the main base material layer 10 is made of polypropylene).

[0381] The main substrate layer 10 may contain organic additives such as antiblocking agents (AB agents), antioxidants, stabilizers, lubricants, and antistatic agents, and may also contain inorganic additives such as silica, zeolite, hydrotalcite, silica particles, and syloid.

[0382] The anti-blocking agent may be either organic particles or inorganic particles. Examples of organic particles include polymethyl methacrylate particles, polystyrene particles, and polyamide particles. Examples of inorganic particles include silica particles, zeolite, talc, kaolinite, and feldspar. These anti-blocking agents may be used alone or in combination of two or more.

[0383] In consideration of anti-blocking performance, it is preferable to use an AB agent with an average particle size of 0.1 to 5 μm, where the average particle size is the weight average diameter measured by the coal tar method.

[0384] The thickness (total thickness) of the main substrate layer 10 is not particularly limited, but may be, for example, 3 μm or more and 200 μm or less, 6 μm or more and 50 μm or less, or 10 μm or more and 30 μm or less.

[0385] The polypropylene used in the main base material layer 10 may be polypropylene polymerized from fossil fuel, recycled polypropylene, or polypropylene obtained by polymerizing raw materials derived from biomass such as plants. When using these polypropylenes, they may be used alone, or a mixture of polypropylene polymerized from fossil fuel and recycled polypropylene or polypropylene obtained by polymerizing raw materials derived from biomass such as plants may be used.

[0386] The main substrate layer 10 can also be used as each layer of a multi-layer laminate. In this embodiment, by using it as the substrate layer 1 of the printed matter 110, adhesion with the anchor coat layer 126 is improved.

[0387] The main substrate layer 10 (or the printed matter 110 including the main substrate layer 10) can be used for the same purposes as in the first embodiment, and can be subjected to treatments for that purpose.

[0388] The first skin layer 121, the second skin layer 123, and the core layer 122 of the main substrate layer 10 will be described below.

[0389] <First Skin Layer> The first skin layer 121 contains a copolymer of propylene and another monomer. The content of the copolymer may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the first skin layer 121. The content of the copolymer may be substantially 100% by mass, based on the total mass of the first skin layer 121.

[0390] Other monomers used in the copolymer may include, for example, α-olefins such as ethylene, 1-butene, and 1-hexene. The first skin layer 121 may contain a copolymer of propylene and an α-olefin. The copolymer may be a random copolymer.

[0391] The content of propylene units in the copolymer may be 80 mol% or more, 90 mol% or more, 95 mol% or more, or 96 mol% or more, and may be 99.7 mol% or less, 99.5 mol% or less, 99 mol% or less, or 98 mol% or less, based on the total amount of monomer units.

[0392] The first skin layer 121 can be formed on the core layer 122, for example, by co-extruding the polypropylene that forms the core layer 122 and a copolymer of propylene and another monomer that forms the first skin layer 121.

[0393] The copolymer used in the first skin layer 121 may be a resin polymerized from a fossil fuel, a recycled resin, or a resin obtained by polymerizing a raw material derived from biomass such as plants. When using these resins, they may be used alone or in combination with a resin polymerized from a fossil fuel and a recycled resin or a resin obtained by polymerizing a raw material derived from biomass such as plants.

[0394] The softening temperature of the first skin layer 121 measured from a cross section of the film by local thermal analysis (LTA) is preferably 120°C or higher. This tends to suppress blocking with other layers (e.g., the substrate vapor deposition layer 127) and further suppress a decrease in the wettability of other layers. The softening temperature of the first skin layer 121 measured from a cross section of the film by local thermal analysis is preferably 170°C or lower. This tends to ensure the flexibility of the first skin layer 121 and ensure sufficient adhesive strength with the core layer 122. The softening temperature may be a temperature measured at the center of the first skin layer 121.

[0395] The thickness of the first skin layer 121 is preferably 0.1 μm or more. A thickness of 0.1 μm or more allows for uniform layering and reduces thickness variation. It is also believed that stress on the substrate vapor deposition layer 127 during heat sterilization can be sufficiently alleviated, thereby suppressing barrier degradation. From this perspective, the thickness of the first skin layer 121 is preferably 0.3 μm or more. On the other hand, there is no particular upper limit on the thickness of the first skin layer 121, but from the perspective of ensuring sufficient heat resistance of the entire main substrate layer 10, it is preferably 2.0 μm or less, and more preferably 1.8 μm or less.

[0396] The ratio of the thickness of the first skin layer 121 to the thickness of the main substrate layer 10 (thickness of the first skin layer 121 / thickness of the main substrate layer 10) may be 1 / 100 to 1 / 5, or 1 / 70 to 1 / 10. When the thickness ratio is within the above range, the heat resistance of the entire main substrate layer 10 can be more sufficiently ensured. Note that when the main substrate layer 10 is used as a gas barrier layer or a laminate material, there is a tendency to be able to further increase the adhesion between these layers and further improve the stability of adhesion.

[0397] (O / C) The O / C ratio preferably has an average value of 0.010 to 0.050 and a standard deviation of 0.0010 to 0.0050. The average O / C ratio is more preferably 0.010 or more, and from the viewpoint of further improving adhesion and further improving adhesion stability, it is even more preferably 0.011 or more, particularly preferably 0.012 or more, and even more preferably 0.015 or more. The average O / C ratio is preferably 0.050 or less, and from the viewpoint of suppressing a decrease in the wettability of other layers, it is more preferably 0.045 or less, even more preferably 0.040 or less, and particularly preferably 0.030 or less. The average value of O / C may be 0.010 or more and 0.050 or less, 0.010 or more and 0.045 or less, 0.010 or more and 0.040 or less, 0.010 or more and 0.030 or less, 0.011 or more and 0.050 or less, 0.011 or more and 0.045 or less, 0.011 or more and 0.040 or less, 0.011 or more and 0.030 or less, 0.012 or more and 0.050 or less, 0.012 or more and 0.045 or less, 0.012 or more and 0.040 or less, 0.012 or more and 0.030 or less, 0.015 or more and 0.050 or less, 0.015 or more and 0.045 or less, 0.015 or more and 0.040 or less, or 0.015 or more and 0.030 or less.

[0398] The standard deviation of O / C is preferably 0.0010 or more, and from the viewpoint of further improving adhesion and further improving adhesion stability, it is more preferably 0.0012 or more, even more preferably 0.0015 or more, and particularly preferably 0.0020 or more. The standard deviation of O / C is preferably 0.0050 or less, and since there is a tendency to obtain a stable surface treatment state with little variation, it is more preferably 0.0045 or less, even more preferably 0.0040 or less, and particularly preferably 0.0035 or less. The standard deviation of O / C is 0.0010 or more and 0.0050 or less, 0.0010 or more and 0.0045 or less, 0.0010 or more and 0.0040 or less, 0.0010 or more and 0.0035 or less, 0.0012 or more and 0.0050 or less, 0.0012 or more and 0.0045 or less, 0.0012 or more and 0.0040 or less, 0.0012 or more and 0.0035 or less , 0.0015 or more and 0.0050 or less, 0.0015 or more and 0.0045 or less, 0.0015 or more and 0.0040 or less, 0.0015 or more and 0.0035 or less, 0.0020 or more and 0.0050 or less, 0.0020 or more and 0.0045 or less, 0.0020 or more and 0.0040 or less, or 0.0020 or more and 0.0035 or less.

[0399] The average value and standard deviation of O / C are determined as follows. That is, the surface of the first skin layer 121 is narrow-spectrum analyzed using the following measuring equipment under the following measurement conditions. This obtains narrow spectra of the O1s and C1s orbitals on the surface of the first skin layer 121. For each of the elements O and C, elemental quantitative values ​​(atomic %) are determined from the respective peak areas using relative sensitivity coefficients of 1.00 eV for C1s and 2.28 eV for O1s. O / C is calculated using the determined elemental quantitative values. The ratio of oxygen atoms to oxygen atoms (O / C) is the atomic ratio. The locations at which O / C is measured may be five locations randomly selected on the surface of the first skin layer 121. The average value and standard deviation of O / C are calculated from the measurement results of the five locations.

[0400] <Measurement equipment> Photoelectron spectrometer JPS-9030 manufactured by JEOL Ltd. <Measurement conditions: spectrum collection conditions> Incident X-ray: MgKα (hν=1253.6 eV) X-ray output: 100 W (10 kV, 10 mA) Measurement area: circular area with a diameter of 6 mm Photoelectron acceptance angle: 15° Dwell time: 100 ms Measurement step: 0.2 eV Pass energy: 10 eV Number of accumulations: 5

[0401] (Second Skin Layer) The second skin layer 123 may contain a copolymer of propylene and another monomer. In the second skin layer 123, the content of the copolymer of propylene and another monomer, the other monomers used in the copolymer, the content of propylene units in the copolymer, the method for forming the second skin layer 123, the softening temperature, and the thickness of the second skin layer 123 may be similar to those of the first skin layer 121. The ratio of the thickness of the second skin layer 123 to the thickness of the main substrate layer 10 may be similar to the ratio of the thickness of the first skin layer 121 to the thickness of the main substrate layer 10.

[0402] (Core Layer) The core layer 122 contains polypropylene. From the viewpoint of enhancing the heat resistance of the main base material layer 10, the polypropylene used for the core layer 122 may be crystalline polypropylene, or from the viewpoint of further improving the heat resistance for heat sterilization treatment, it may be homopolypropylene, which is a homopolymer of propylene. However, as long as the effects of the present invention are not significantly impaired, a random copolymer of propylene and an α-olefin, or a mixture of such a copolymer with homopolypropylene, may also be used.

[0403] The polyolefin used in the core layer 122 may be a polyolefin polymerized from a fossil fuel, a recycled polyolefin, or a polyolefin obtained by polymerizing a raw material derived from biomass such as plants. When using these polyolefins, they may be used alone, or a mixture of a polyolefin polymerized from a fossil fuel and a recycled polyolefin or a polyolefin obtained by polymerizing a raw material derived from biomass such as plants may be used.

[0404] When the main substrate layer 10 has a first skin layer 121 and a second skin layer 123, the core layer 122 disposed between the first skin layer 121 and the second skin layer 123 does not need to contain an AB agent.

[0405] From the viewpoint of maintaining the workability and ease of handling of the main substrate layer 10, the thickness of the core layer 122 may be 10 to 200 μm, 12 to 50 μm, or 15 to 30 μm.

[0406] Here, if a stretched polypropylene film (OPP film) is used as any of the first skin layer 121, core layer 122, and second skin layer 123, heat resistance may be reduced. To improve heat resistance, it is effective to use homopolypropylene, which has high heat resistance, as the material for the OPP film. On the other hand, OPP films formed from homopolypropylene tend to have weaker adhesion to adjacent layers than OPP films formed from other propylenes. However, by using a core layer containing homopropylene and using propylenes other than homopropylene for the first skin layer 121 and second skin layer 123, the OPP film obtained by stretching the laminate of these layers has excellent heat resistance and adhesion resistance.

[0407] (Surface Treatment) The surfaces of the first skin layer 121 and the second skin layer 123 of the main substrate layer 10 may be surface-treated using a conventionally known surface treatment device. Examples of such surface treatments include corona treatment, plasma treatment, and flame treatment. Among these surface treatments, plasma treatment is preferred because it can be performed effectively at low temperature and in a short time, and because the degree of treatment is stable over time. Plasma treatment can be performed, for example, under atmospheric pressure or in a vacuum, and is preferably performed in a vacuum to achieve a stable, high degree of treatment. Furthermore, plasma treatment in a vacuum can be performed simultaneously with the process of forming the substrate vapor deposition layer 127.

[0408] Examples of the apparatus used for the plasma treatment include conventionally known plasma treatment apparatuses. By using such an apparatus, it is possible to suppress the occurrence of abnormal discharge such as arc discharge even when high power is input, and to perform stable plasma treatment for a long period of time. The gas used for the plasma treatment is not particularly limited as long as it can generate plasma, and examples thereof include argon (Ar), helium (He), nitrogen (N ２ ), oxygen (O ２ ) etc.

[0409] The substrate layer 1 includes, from the main substrate layer 10 side, an anchor coat layer 126, a vapor deposition layer 127, and a gas barrier coating layer 128 in this order.

[0410] (Anchor Coat Layer) The anchor coat layer 126 is a layer for further improving the adhesion between the main substrate layer 10 and the vapor deposition layer 127, and is provided between the main substrate layer 10 and the vapor deposition layer 127. The material constituting the anchor coat layer 126 may be any material that can improve the adhesion between the main substrate layer 10 and the vapor deposition layer 127, and is not particularly limited.

[0411] For example, a material containing a reaction product of a polyol compound containing a (meth)acrylic resin and an isocyanate compound can be used as the material for the anchor coat layer 126. Note that the term "(meth)acrylic resin" refers to at least one of "acrylic resin" and the corresponding "methacrylic resin."

[0412] Examples of (meth)acrylic resins include (meth)acrylic polymers obtained by polymerizing polymerizable monomers containing (meth)acrylic monomers. The (meth)acrylic polymers may be homopolymers or copolymers with polymerizable monomers other than (meth)acrylic monomers. The (meth)acrylic resin may be a resin capable of thermal crosslinking, such as urethane curing or epoxy curing. In view of reactivity with an isocyanate compound used as a curing agent, which will be described later, the (meth)acrylic resin may be a polyol having two or more hydroxyl groups in one molecule, and in particular, may be a (meth)acrylic polyol.

[0413] The (meth)acrylic polyol may be a (meth)acrylic copolymer obtained by copolymerizing a hydrocarbon (meth)acrylate with a hydroxyl group-containing monomer, or a (meth)acrylic copolymer obtained by copolymerizing a hydrocarbon (meth)acrylate, a hydroxyl group-containing monomer, and a monomer component other than these (other monomer component). By copolymerizing the above monomers, a (meth)acrylic polyol containing multiple hydroxyl groups can be obtained.

[0414] The anchor coat layer 126 may contain a curing agent. The curing agent may be an isocyanate-based compound having two or more NCO groups in the molecule, from the viewpoint of excellent reactivity with the (meth)acrylic resin.

[0415] The isocyanate compound may be a monomeric isocyanate. Examples of the monomeric isocyanate include aromatic or araliphatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), and tetramethylxylylene diisocyanate (TMXDI); and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), bisisocyanate methylcyclohexane (H6XDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (H12MDI).

[0416] The isocyanate compound may be a polymer or derivative of the above-mentioned monomeric isocyanate. The isocyanate compound may be, for example, a trimer nurate type, an adduct type reacted with trimethylolpropane, or a biuret type reacted with biuret. The isocyanate compound may be an isocyanate having an aromatic ring from the viewpoint of excellent reactivity with the (meth)acrylic resin.

[0417] When the (meth)acrylic resin is a (meth)acrylic polyol, the content of the isocyanate compound may be an amount such that the number of OH groups in the acrylic polyol is equal to the number of NCO groups in the isocyanate compound.

[0418] The anchor coat layer 126 may contain a silane coupling agent from the viewpoint of further improving adhesion to the vapor deposition layer 127. Examples of the silane coupling agent include an epoxy-based silane coupling agent having an epoxy group such as 3-glycidoxypropyltrimethoxysilane, an amino-based silane coupling agent having an amino group such as 3-aminopropyltrimethoxysilane, a mercapto-based silane coupling agent having a mercapto group such as 3-mercaptopropyltrimethoxysilane, and an isocyanate-based silane coupling agent having an NCO group such as 3-isocyanatepropyltriethoxysilane. These silane coupling agents can be used alone or in combination of two or more.

[0419] Alternatively, a urethane-based resin formed from an acid group-containing polyurethane and a polyamine can be used as a material for the anchor coat layer 126. The urethane-based resin is obtained by bonding the acid groups of the acid group-containing polyurethane with the amino groups of a polyamine used as a crosslinker. In other words, the urethane-based resin can be said to be a reaction product of the acid group-containing polyurethane and the polyamine, or to be formed by crosslinking the acid group-containing polyurethane with the polyamine. The bond between the acid group of the acid group-containing polyurethane and the amino group of the polyamine may be an ionic bond (e.g., an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (e.g., an amide bond).

[0420] A silane coupling agent or a carbodiimide compound may be added to the urethane resin. By adding such a compound, a cross-linked structure is formed with the urethane resin, which can further improve the gas barrier properties and the adhesion between the main substrate layer 10 and the vapor deposition layer 127. Commonly used silane coupling agents can be used, such as compounds in which an alkoxy group and an organic reactive group are bonded to a silicon atom.

[0421] The thickness of the anchor coat layer 126 is not particularly limited as long as it is capable of improving the adhesion between the main substrate layer 10 and the substrate vapor deposition layer 127, but is preferably 30 nm or more. In this case, compared to when the thickness of the substrate anchor coat layer 126 is less than 30 nm, the surface smoothness of the anchor coat layer 126 can be further improved, the thickness of the vapor deposition layer 127 can be made more uniform, and the oxygen barrier property can also be further improved. Therefore, the oxygen barrier property of the substrate layer 1 can be further improved. The thickness of the anchor coat layer 126 is more preferably 40 nm or more, and even more preferably 50 nm or more. By increasing the thickness of the anchor coat layer 126, it is possible to further suppress the deterioration of the water vapor barrier property when an external force such as stretching is applied.

[0422] The thickness of the anchor coat layer 126 is preferably 2,000 nm (2 μm) or less. In this case, the flexibility of the base material layer 1 is further improved compared to when the thickness of the anchor coat layer 126 exceeds 2,000 nm, and the oxygen gas barrier properties of the base material layer 1 after abuse can be further improved. The thickness of the anchor coat layer 126 is more preferably 1,500 nm (1.5 μm) or less.

[0423] The anchor coat layer 126 can be formed, for example, by applying an anchor coat solution onto the resin layer by a method such as gravure coating, roll coating, or bar coating, and then drying it.

[0424] In order to improve the adhesion between the main substrate layer 10 and the vapor deposition layer 127, a surface treatment such as plasma treatment or corona treatment may be performed on the surface of the main substrate layer 10 on which the vapor deposition layer 127 is to be formed, instead of the anchor coat layer 126. The anchor coat layer 126 may also be provided on the surface of the main substrate layer 10 that has been subjected to a surface treatment.

[0425] (Vapor-deposited layer) The vapor-deposited layer 127 contains an inorganic oxide. From the viewpoint of improving gas barrier properties against water vapor, oxygen, etc., the vapor-deposited layer 127 may be formed directly on the anchor coat layer 126. The vapor-deposited layer 127 may be transparent.

[0426] Examples of inorganic oxides that can be used include aluminum oxide, silicon oxide, tin oxide, magnesium oxide, and mixtures thereof. From the viewpoint of excellent sterilization resistance, the inorganic oxide may be at least one selected from aluminum oxide and silicon oxide.

[0427] The thickness of the vapor deposition layer 127 may be 5 nm or more, 10 nm or more, or 15 nm or more from the viewpoints of achieving a uniform film thickness and excellent gas barrier properties, and may be 300 nm or less, 150 nm or less, or 100 nm or less from the viewpoint of making it difficult for cracks to occur in the vapor deposition layer 127 even when an external force is applied after film formation. From these viewpoints, the thickness of the substrate vapor deposition layer 127 may be 5 to 300 nm, 10 to 150 nm, or 15 to 100 nm.

[0428] The vapor deposition layer 127 can be formed by, for example, a vacuum vapor deposition method, a plasma-assisted method, an ion-beam-assisted method, a sputtering method, a reactive vapor deposition method, etc. The vapor deposition layer 127 may be formed by a vacuum vapor deposition method from the viewpoint of excellent productivity, or may be formed by a plasma-assisted method or an ion-beam-assisted method from the viewpoint of excellent adhesion between the vapor deposition layer 127 and the resin layer and improving the density of the vapor deposition layer 127, or may be formed by a reactive vapor deposition method in which various gases such as oxygen are blown in from the viewpoint of excellent transparency of the vapor deposition film.

[0429] Examples of the heating means for the vacuum deposition method include an electron beam heating method, a resistance heating method, an induction heating method, etc. The heating means for the vacuum deposition method may be an electron beam heating method, from the viewpoint of an excellent range of selectivity for evaporation materials.

[0430] The vapor deposition layer 127 may be a metal vapor deposition layer. The metal vapor deposition layer is provided on the above-mentioned base film from the viewpoint of improving gas barrier properties against water vapor and oxygen, for example, and from the viewpoint of light blocking properties. The metal vapor deposition layer is a vapor deposition layer containing a metal. From the viewpoint of gas barrier properties and light blocking properties, aluminum is preferred as the metal. The metal vapor deposition layer is preferably an aluminum vapor deposition layer formed by vapor-depositing aluminum.

[0431] The thickness of the metal vapor deposition layer may be 5 to 300 nm. If the thickness of the metal vapor deposition layer is 5 nm or more, a film with a uniform and sufficient thickness is easily obtained, allowing the substrate barrier layer 15 to fully exhibit its functions and making it easier to obtain better light-blocking properties. Furthermore, if the thickness of the metal vapor deposition layer is 300 nm or less, flexibility can be imparted to the metal vapor deposition layer, making it less likely to crack even if external factors such as bending or pulling are applied after film formation. From this perspective, the thickness of the metal vapor deposition layer is preferably 6 nm or more, more preferably 150 nm or less, and even more preferably 100 nm or less.

[0432] The metal vapor deposition layer can be formed by a conventional vacuum deposition method. Other thin film formation methods, such as sputtering, ion plating, and plasma vapor deposition (CVD), can also be used. However, considering productivity, vacuum deposition is currently the most advantageous method. As a heating method for vacuum deposition, it is preferable to use one of electron beam heating, resistance heating, and induction heating. However, considering the wide range of evaporation material options, electron beam heating is more preferable. Furthermore, in order to improve the adhesion between the metal vapor deposition layer and the main substrate layer 10 and the density of the metal vapor deposition layer, deposition can also be performed using a plasma-assisted method or an ion beam-assisted method. Furthermore, in order to increase the transparency of the vapor deposition film, reactive deposition, in which various gases such as oxygen are blown in during deposition, may be used.

[0433] (Gas Barrier Coating Layer for Substrate) When the substrate layer 1 is provided with the gas barrier coating layer 128, the vapor deposition layer 127 can be protected, and the gas barrier properties can be further improved.

[0434] The gas barrier coating layer 128 may contain a silicon compound or a hydrolyzate thereof, and a water-soluble polymer having a hydroxyl group.

[0435] Examples of silicon compounds include Si(OR １ ) ４ and R ２ Si(OR ３ ) ３ The compound may be one or more selected from the group consisting of: OR １ and OR３ are each independently a hydrolyzable group, and R ２ is an organic functional group. ２ Examples of the alkyl group include a vinyl group, an epoxy group, a methacryloxy group, a ureido group, and an isocyanate group. １ ) ４ is relatively stable in aqueous solvents after hydrolysis, so tetraethoxysilane (Si(OC ２ H ５ ) ４ ) may be.

[0436] Examples of water-soluble polymers having hydroxyl groups include polyvinyl alcohol, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. As the water-soluble polymer having hydroxyl groups, polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH) are preferred from the viewpoint of excellent gas barrier properties, and EVOH is more preferred from the viewpoint of heat resistance and gas barrier properties.

[0437] Examples of PVA include resins obtained by homopolymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate, followed by saponification.

[0438] A coating liquid containing a polyvinyl alcohol-based resin and a liquid medium can be used to form the gas barrier coating layer 128. The coating liquid can be obtained, for example, by dissolving a powder of a polyvinyl alcohol-based resin obtained by synthesis in a liquid medium. Examples of liquid media include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. These may be used alone or in combination. From the perspective of reducing environmental impact, water can be used as the liquid medium. In this case, the coating liquid can be obtained by dissolving a powder of a polyvinyl alcohol-based resin in water at a high temperature (e.g., 80°C).

[0439] The content of the polyvinyl alcohol resin (solid content) in the coating solution can be 3 to 20% by mass in order to maintain good coating properties. The coating solution may contain additives such as isocyanate and polyethyleneimine to improve adhesion. The coating solution may also contain additives such as preservatives, plasticizers (alcohols, etc.), surfactants, etc.

[0440] The coating liquid can be applied to the vapor deposition layer 127 by any appropriate method. The coating liquid can be applied by a wet film formation method using, for example, a gravure coater, a dip coater, a reverse coater, a wire bar coater, or a die coater. The application temperature and drying temperature of the coating liquid are not particularly limited and can be, for example, 50°C or higher.

[0441] The gas barrier coating layer 128 may be formed on the vapor deposition layer 127 by extrusion. In this case, multilayer extrusion using a T-die can be employed. Examples of adhesives that can be used during extrusion include two-component curing polyurethane adhesives, in which a base material such as polyester polyol, polyether polyol, or acrylic polyol is reacted with a bifunctional or higher aromatic or aliphatic isocyanate compound as a curing agent. The adhesive components may be applied to the vapor deposition layer 127 and then dried to form an adhesive layer on the vapor deposition layer 127. When using a urethane resin adhesive, aging the adhesive for at least four days at 40°C after application promotes the reaction between the hydroxyl groups of the base material and the isocyanate groups of the curing agent, thereby achieving strong adhesion. The thickness of the adhesive layer can be 0.05 to 2 μm, or 0.1 to 1 μm, depending on adhesion, conformability, processability, and other factors.

[0442] The gas barrier coating layer 128 may further contain additives such as the above-mentioned isocyanate compounds, silane coupling agents, dispersants, stabilizers, viscosity adjusters, and colorants.

[0443] The thickness of the gas barrier coating layer 128 may be 0.1 μm or more, or 0.3 μm or more, and may be 5 μm or less, or 1 μm or less. The thickness of the gas barrier coating layer 128 may be 0.1 to 5 μm, or 0.3 to 1 μm.

[0444] The gas barrier coating layer 128 can be formed, for example, by dissolving a water-soluble polymer in water or a water / alcohol mixed solvent, mixing in a silicon compound or a hydrolyzate thereof, applying the mixed solution onto the vapor deposition layer 127 by a method such as gravure coating, roll coating, or bar coating, and drying it.

[0445] When the water-soluble polymer is polyvinyl alcohol, the content of polyvinyl alcohol in the mixed solution may be 20% by mass or more or 25% by mass or more based on the total solid content of the mixed solution from the viewpoint of facilitating the formation of the gas barrier coating layer 128 for a substrate, and may be 50% by mass or less or 40% by mass or less from the viewpoint of excellent gas barrier properties. The content of polyvinyl alcohol in the mixed solution may be 20 to 50% by mass or 25 to 40% by mass based on the total solid content of the mixed solution.

[0446] The substrate layer 1 may not have the anchor coat layer 126, may not have the gas barrier coating layer 128, or may not have both the anchor coat layer 126 and the gas barrier coating layer 128. Furthermore, the substrate layer 1 may have the gas barrier coating layer 128 between the main substrate layer 10 and the vapor deposition layer 127.

[0447] When the main substrate layer 10 is an oriented polypropylene (OPP) film, an organic compound such as propyl myristate is typically added as a nucleating agent for crystals necessary for producing the OPP film. If such an organic compound bleeds onto the surface of the printed matter 110 opposite the sealant layer 2, it may adhere to the sealant layer 2 and migrate, potentially contaminating the contents, when the printed matter 110 is produced and wound up. Furthermore, irradiation with active energy rays may alter the organic compound or other components, potentially generating compounds that are more prone to bleeding. Migration of the bleed material into the sealant layer 2 is undesirable from a food hygiene perspective, and therefore must be suppressed. In this regard, by providing the printed matter 110 with the protective layer 6, the protective layer 6 is interposed between the substrate layer 1 and the sealant layer 2 when the printed matter 110 is wound up, thereby suppressing migration of the bleed material to the adjacent sealant layer 2 during winding. Furthermore, by providing the printed matter 110 with the anchor coat layer 126, the vapor deposition layer 127, the gas barrier coating layer 128, etc., migration of the bleeding body within the printed matter 110 to the sealant layer 2 can be suppressed.

[0448] It is preferable to subject the surface of the substrate layer 1 to plasma treatment. This changes the wettability of the surface, and this change in wettability causes hydroxyl groups (OH groups) of compounds present on the surface to rise from the surface, thereby improving the adhesion between the substrate layer 1 and adjacent layers. Furthermore, by laminating the gas barrier coating layer 128 as described above on the surface of the vapor deposition layer 127 of the substrate layer 1, the adhesion between the substrate layer 1 and the ink layer 4 can be improved.

[0449] [Modified Layer] The modified layer 3 may be formed of a polyurethane resin obtained by reacting a difunctional or higher isocyanate compound with, for example, polyester polyol, polyether polyol, acrylic polyol, carbonate polyol, or the like.

[0450] In order to improve adhesiveness, the modified layer 3 may contain, in addition to the urethane resin, a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, or the like.

[0451] The thickness of the modified layer 3 is not particularly limited and may be, for example, 0.1 μm or more. By making the thickness of the modified layer 3 1 μm or more, sufficient adhesive strength can be obtained. The thickness of the modified layer 3 may be 2 μm or more. The thickness of the modified layer 3 may be 50 μm or less, 5 μm or less, or 3 μm or less.

[0452] [Sealant Layer] The sealant layer 2 includes a polypropylene film. The polypropylene film includes polypropylene. The polypropylene film may be, for example, a film obtained by forming polypropylene into a sheet and then stretching it to be uniaxially or biaxially oriented.

[0453] The polypropylene content may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the sealant layer 2. The polypropylene content may be substantially 100% by mass, based on the total mass of the sealant layer 2 (an embodiment in which the sealant layer 2 is made of polypropylene).

[0454] The thickness of the sealant layer 2 may be 10 μm or more, or 20 μm or more, and may be 200 μm or less, or 100 μm or less. The thickness of the sealant layer 2 may be 10 to 200 μm, or 20 to 100 μm.

[0455] <Protective Layer> The protective layer 6 includes a polypropylene film. The polypropylene film includes polypropylene. The polypropylene film may be, for example, a film obtained by forming polypropylene into a sheet and then stretching it to be uniaxially or biaxially oriented.

[0456] The protective layer 6 can be provided by bonding it to another adjacent film via an adhesive, such as a two-component curing urethane adhesive.

[0457] The polypropylene may be crystalline polypropylene. From the viewpoint of improving heat resistance, the polypropylene may be homopolypropylene, which is a homopolymer of propylene. The polypropylene may contain, for example, a random copolymer of propylene and an α-olefin.

[0458] The polypropylene content may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the protective layer 6. The polypropylene content may be substantially 100% by mass, based on the total mass of the protective layer 6 (an embodiment in which the protective layer 6 is made of polypropylene).

[0459] The protective layer 6 may contain organic additives such as an antiblocking agent (AB agent), an antioxidant, a stabilizer, a lubricant, and an antistatic agent, or may contain inorganic additives such as silica, zeolite, hydrotalcite, silica particles, and syloid.

[0460] The anti-blocking agent may be either organic particles or inorganic particles. Examples of organic particles include polymethyl methacrylate particles, polystyrene particles, and polyamide particles. Examples of inorganic particles include silica particles, zeolite, talc, kaolinite, and feldspar. These anti-blocking agents may be used alone or in combination of two or more.

[0461] In consideration of anti-blocking performance, it is preferable to use an AB agent with an average particle size of 0.1 to 5 μm, where the average particle size is the weight average diameter measured by the coal tar method.

[0462] The thickness (total thickness) of the protective layer 6 is not particularly limited, and may be, for example, 3 μm to 200 μm, 6 μm to 50 μm, or 10 μm to 30 μm.

[0463] The polypropylene used in the protective layer 6 may be a resin polymerized from fossil fuel, may be recycled polypropylene, or may be polypropylene obtained by polymerizing raw materials derived from biomass such as plants. When using these polypropylenes, they may be used alone, or may be used as a mixture of polypropylene polymerized from fossil fuel and recycled polypropylene or polypropylene obtained by polymerizing raw materials derived from biomass such as plants.

[0464] The heat resistance of the printed matter 110 also requires heat resistance for the seal bar (i.e., heat resistance of the base layer 1 containing polypropylene). In order to enhance this heat resistance, the protective layer 6 is preferably a heat-resistant layer, and the heat-resistant layer preferably contains an active energy ray (e.g., electron beam) curable resin. By including an active energy ray curable resin in the heat-resistant layer, after applying (printing) ink to the base layer 1 and applying a heat-resistant layer-forming material, the ink layer 4 and the heat-resistant layer can be formed simultaneously by irradiating the base layer 1 with active energy rays once.

[0465] When the printed matter 110 is used as a packaging material with a spout, the spout portion and the entire spout of the cap may be formed from the same resin as the main base material layer 10 in order to improve recyclability.

[0466] <Use> The printed matter 110 can be used for the same purpose as the printed matter 108 of the eighth embodiment.

[0467] [Eleventh embodiment] Fig. 12 is a cross-sectional view schematically showing the layer structure of a printed matter according to an eleventh embodiment of the present invention. The printed matter 111 shown in Fig. 12 is a laminate formed by reverse offset printing. The printed matter 111 includes, from the top (surface side), a protective layer 6, a substrate layer 1, an ink layer 4, a modified layer 3, a barrier layer 5, an adhesive layer 7, and a sealant layer 2, in this order.

[0468] The printed matter 111 has a configuration in which the substrate layer 1 includes only the main substrate layer 10, and has the same configuration as the printed matter 110, except that it further includes a barrier layer 5 and an adhesive layer 7. Like the printed matter 110, the printed matter 111 has a configuration that is particularly preferable for achieving mono-materialization. The ink layer 4, modified layer 3, and sealant layer 2 included in the printed matter 111 have the same configurations as those described in the tenth embodiment, and the printing method and active energy ray irradiation method can also be the same as those in the tenth embodiment.

[0469] <Substrate Layer> The substrate layer 1 includes a main substrate layer 10 similar to that of the printed matter 110. The configuration of the main substrate layer 10 is the same as that of the tenth embodiment, and therefore detailed description thereof will be omitted. Note that the substrate layer 1 may include an anchor coat layer, a vapor deposition layer, a gas barrier coating layer, etc., similar to those of the tenth embodiment.

[0470] <Barrier Layer> The barrier layer 5 has, from the modified layer 3 side, a gas barrier layer 52 and a barrier substrate layer 51 in this order. The barrier substrate layer 51 has a configuration similar to that of the main substrate layer 10 of the substrate layer 1 of the printed matter 110. Specifically, the barrier substrate layer 51 has a first skin layer 514, a core layer 515, and a second skin layer 516 that are similar to the first skin layer 121, the core layer 122, and the second skin layer 123, respectively, of the main substrate layer 10. The gas barrier layer 52 has an anchor coat layer 523, a vapor deposition layer 524, and a gas barrier coating layer 525 that are similar to the anchor coat layer 126, the vapor deposition layer 127, and the gas barrier coating layer 128, respectively, in the substrate layer 1 of the printed matter 110. The barrier layer 5 includes a first skin layer 514, a core layer 515, a second skin layer 516, an anchor coat layer 523, a vapor deposition layer 524, and a gas barrier coating layer 525 laminated in this order. Therefore, a detailed description of the barrier layer 5 will be omitted.

[0471] <Adhesive Layer> As the adhesive layer 7, the same adhesive layer as the adhesive layer 7 in the ninth embodiment can be used.

[0472] The printed matter 111 may contain 90% by mass or more of the same type of resin (polypropylene). In this case, the printed matter 111 may be configured as a highly recyclable mono-material. Alternatively, even in the case of an olefin-based resin, from the perspective of recycling, the printed matter 111 may have a mono-olefin configuration in which the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based group, at 90% by mass or more.

[0473] As described above, the printed matter 111 of this embodiment has the same effects as the printed matter 110 of the tenth embodiment. In addition, the printed matter 111 also has the barrier properties due to the barrier layer 5.

[0474] <Use> The printed matter 111 can be used for the same purposes as the printed matter 110 of the tenth embodiment.

[0475] Based on the above findings, the inventors have created a printing medium that improves adhesion to the ink layer as well as strength and flexibility by appropriately reducing the irradiation dose. A twelfth embodiment of the printing medium of the present invention will be described. The printing medium of the present invention also includes products obtained by irradiating with active energy rays. In this case, as described above, the mechanism by which irradiation with active energy rays improves adhesion to the ink, strength, and flexibility has not been fully elucidated. Therefore, it may be considered impractical to completely define the structure of the printing medium of the present invention as a product.

[0476] [Twelfth Embodiment] In the twelfth embodiment, a resin substrate layer containing recycled material is used as the substrate layer in the printed matter according to the second embodiment. That is, a printed matter 112 (not shown) of the twelfth embodiment includes, from the top (surface side), a substrate layer 1, an ink layer 4, a modified layer 3, and a sealant layer 2, in this order, as in FIG. 3 , and the substrate layer 1 is a resin substrate layer containing recycled material. The printed matter 112 has the same configuration as the printed matter 102, except that a resin substrate layer containing recycled material is used as the substrate layer 1. The ink layer 4, modified layer 3, and sealant layer 2 included in the printed matter 112 have the same configurations as those described in the second embodiment, and the printing method and the active energy ray irradiation method can also be the same as those in the second embodiment.

[0477] Compared to resin substrate layers made of petroleum-derived resins, resin substrate layers containing recycled materials may contain impurities, which may result in the presence of foreign matter such as fish eyes. Therefore, the surface of the resin substrate layer, which is the printing surface, may not be highly smooth or may not be uniform, and may have inferior printability compared to resin substrate layers made of petroleum-derived resins. However, by performing offset printing using an active energy ray-curable ink containing an active energy ray-curable resin, the printed matter 112 of this embodiment can be printed with high precision even on resin substrate layers containing recycled materials.

[0478] <Resin substrate layer containing recycled material> Examples of resin substrate layers containing recycled materials include material recycled polyethylene terephthalate (PET) films, chemically recycled polyethylene terephthalate (PET) films, material recycled polyethylene (PE) films, chemically recycled polyethylene (PE) films, material recycled polypropylene (PP) films, chemically recycled polypropylene (PP) films, material recycled nylon (NY) films, and chemically recycled nylon (NY) films. These resin substrate layers containing recycled materials may be single-layered or multi-layered. For example, the resin substrate layer containing recycled materials may be a three-layer co-extruded film of a resin film made of a petroleum-derived resin, a resin film made of a recycled resin, and a resin film made of a petroleum-derived resin. It is also possible to use a laminated film of a resin film made of a recycled resin and a biomass-derived resin film. The resin substrate layer containing recycled materials may also be a resin film made of a mixture of recycled resin pellets and petroleum-derived resin pellets. For example, a resin substrate layer containing recycled material with a recycled resin ratio of 80% can be obtained by mixing recycled resin pellets and petroleum-derived resin pellets in a ratio of 8:2 to form a film. The mixing ratio of recycled resin pellets to petroleum-derived resin pellets can be any ratio from the viewpoints of the quality, physical properties, cost, etc. required for the recycled material. Furthermore, the resin film made of a mixture of recycled resin pellets and petroleum-derived resin pellets may be a single layer or a multi-layer. When the resin substrate layer containing recycled material is a multi-layer, it may be a laminate of multiple resin films made of a mixture of recycled resin pellets and petroleum-derived resin pellets, or it may be a laminate of a resin film made of recycled resin pellets with a resin film made of petroleum-derived resin pellets or a resin film made of biomass-derived resin pellets.

[0479] <Use> The printed matter 112 can be used for the same purposes as the printed matter 102 of the second embodiment.

[0480] [Thirteenth Embodiment] The thirteenth embodiment is a print medium comprising a substrate layer suitable for use as the substrate layer 1 in the printed matter according to the first to twelfth embodiments. Therefore, when a printed matter is constructed using the print medium of this embodiment as a substrate layer, the same configuration as that of the first to twelfth embodiments can be adopted, except for the substrate layer 1. Furthermore, the print medium can appropriately adopt the configuration of the substrate layer 1 in the first to twelfth embodiments, except for the following configuration. Furthermore, the substrate layer of the print medium may be a single layer or multiple layers, as in the first embodiment, and if it is a multiple layer, it may include an easy-adhesion layer, a barrier layer, etc., or may include multiple barrier layers, and may be surface-treated.

[0481] When the printing medium of this embodiment is adhered to another layer, either the modified layer 3 of the first embodiment or the adhesive layer 7 of the third embodiment may be used as the adhesive layer, but by using the modified layer 3, the adhesion between the base layer 1 and the ink layer 4 is further improved.

[0482] The printing medium of this embodiment is a printing medium suitable for active energy ray offset printing, and has a substrate layer that has affinity with at least an active energy ray curable resin, thereby improving adhesion to ink.

[0483] By providing a printing medium with a substrate layer that has affinity for at least the active energy ray-curable resin, the ink can maintain high adhesion to the substrate layer even after the ink is cured by irradiation with active energy rays. It is believed that irradiation with active energy rays suppresses crosslinking (covalent bonds) in the substrate layer, and that electrostatic interactions (ionic bonds, hydrogen bonds, dipole interactions, van der Waals forces, etc.), which are weaker than crosslinking, act between the substrate layer and other layers, such as the ink layer, thereby enhancing adhesion between the substrate layer and the ink layer. Furthermore, it is believed that suppressing unnecessary crosslinking within the substrate layer also enhances the strength of the substrate layer.

[0484] An ink layer is formed on a printing medium by offset printing, and the ink layer is irradiated with active energy rays. During this process, not only the ink layer but also the printing medium is irradiated with active energy rays. Therefore, it is important to appropriately set the acceleration voltage and exposure dose of the active energy rays.

[0485] <Acceleration voltage of active energy rays> The acceleration voltage of active energy rays can be appropriately set in relation to the irradiation dose so as to suppress unnecessary crosslinking in the substrate layer. Particularly considering the point of causing a curing reaction of the ink layer, the acceleration voltage is preferably as low as possible, for example, 120 kV or less. By setting the acceleration voltage below the above upper limit, in combination with setting the irradiation dose within the above range, unnecessary crosslinking between resin molecules in the substrate layer can be suppressed. The lower limit of the acceleration voltage may be, for example, 10 kV or more, 30 kV or more, or 50 kV or more.

[0486] <Irradiation Dose of Active Energy Rays> To improve adhesion between the substrate layer and the ink layer, the irradiation dose of active energy rays, in the case of electron beams, is preferably 10 to 100 kGy, more preferably 20 to 60 kGy, and even more preferably 25 to 50 kGy. By setting the irradiation dose within the above range, unnecessary crosslinking between resin molecules in the substrate layer can be suppressed, thereby improving adhesion with the ink layer. It is also possible to increase the strength of the print medium. From this perspective, a printed matter using the printing medium of this embodiment comprises an ink layer containing an active energy ray-curable resin and a substrate layer having affinity for the active energy ray-curable resin, and is preferably irradiated with electron beams at a dose of preferably 10 to 100 kGy, more preferably 20 to 60 kGy, and even more preferably 25 to 50 kGy.

[0487] <Crystallization of Printing Medium> When the substrate layer is made of a crystalline material such as polyethylene, irradiation with active energy rays can change the crystallinity of the resin in the substrate layer compared to before irradiation. Therefore, by using the crystallinity of the substrate layer after irradiation as an indicator, it is possible to understand the effects on adhesion to the ink layer, strength of the substrate layer, etc. The crystallinity of the substrate layer can be measured by grazing incidence X-ray diffraction. Measurement by grazing incidence X-ray diffraction can be performed, for example, using an X-ray diffractometer (ATX-G, manufactured by Rigaku Corporation) under the following conditions. X-ray source: CuKα Voltage, current: 50 kV, 300 mA Filter: Kβ removal (Ni) filter Scanning method: parallel beam Scanning axis: 2θ method, a) fixed angle = 0.10°, b) fixed angle = 0.12° Scanning speed: 4° / min Sampling speed: 0.020° / min Measurement range: 10° < 2θ < 30° or 35° Detector: scintillation counter detector (i.e., zero-dimensional detector) Sample stage control mode: fixed Divergence (DS) slit: 0.1 mm Vertical limiting slit: 10 mm Sample installation conditions: When the incident angle is extremely small, at a fixed angle of around 0.1°, the horizontality and smoothness of the sample surface to be measured become important. Therefore, a glass slide (length: 2.6 cm × width: 7.5 cm × thickness: 1 mm) was attached to the sample stage, and a PE film sample was placed on top of it. The protruding portions of the glass slide were then pulled and attached with tape (fixing tape) to ensure a horizontal and smooth measurement surface. The sample stage was then set on the sample stage so that the slide's long axis was aligned with the X-ray incidence direction (see Figure 14).

[0488] The active energy ray exposure dose is preferably set to 10 to 100 kGy, more preferably 20 to 60 kGy, and even more preferably 25 to 50 kGy. This is suitable when the substrate layer is primarily composed of polyethylene (PE). In this case, the substrate layer, which is a crystalline material irradiated with active energy rays, is designed so that the intensity ratio R, expressed by the following formula (1): R = (I1 + I2) / I0 (1), is 2 to 20 in an X-ray diffraction pattern measured by grazing incidence X-ray diffraction measurement using a zero-dimensional detector and the 2θ method with CuKα radiation, where I0 is the intensity of the amorphous peak, I1 is the intensity of the first peak (110) plane, and I2 is the intensity of the second peak (200) plane. When the PE of the substrate layer is high-density polyethylene (HDPE), the intensity ratio R is preferably 14 to 20. When the PE of the substrate layer is low-density polyethylene (LDPE), the intensity ratio R is preferably 2 to 3. When the PE of the substrate layer is linear low density polyethylene (LLDPE), the strength ratio R is preferably 6 to 7. Of these, it is more preferable for the substrate layer to be HDPE or LLDPE.

[0489] Furthermore, the detectors used in grazing incidence X-ray diffraction measurements using the 2θ method with CuKα radiation are limited to zero-dimensional detectors. Zero-dimensional detectors include scintillation counter detectors, which have long been installed in X-ray diffraction instruments, as well as semiconductor detectors, which have recently become capable of selecting zero-dimensional, one-dimensional, or two-dimensional measurement modes. The differences between zero-dimensional and multidimensional (one-dimensional, two-dimensional) detectors are as follows: Because zero-dimensional detectors lack positional information on the detection surface, the angle of the light-receiving arm on which the detector is mounted becomes the "diffraction angle" on the profile, allowing for point-by-point detection. In contrast, one-dimensional detectors are arranged with numerous elongated semiconductor detector elements, which possess positional information in the 2θ direction on the detection surface, and which integrate the X-ray intensities counted by each element to produce a highly sensitive output. Two-dimensional detectors also have numerous square semiconductor detector elements, which possess positional information on the detection surface in both 2θ and the perpendicular χ direction (β direction on the data), enabling even more sensitive output and enabling the diffracted X-rays to be captured as a two-dimensional diffraction image.

[0490] However, since the detection principles differ between zero-dimensional and multidimensional (one-dimensional, two-dimensional) systems, there is a slight difference in the intensity ratio between the detected halo peaks derived from amorphous materials and the diffraction peaks derived from crystalline materials. Therefore, in the present invention, we have limited the scope to the zero-dimensional detectors (scintillation counter detectors and zero-dimensional semiconductor detectors) actually used in the measurements.

[0491] By setting the intensity ratio R within the above range, the adhesion of the substrate layer to other layers such as an ink layer can be improved. Furthermore, strength, for example, puncture resistance, can be increased, and flexibility can also be improved. Therefore, in a printing medium, the substrate layer is made of a crystalline material irradiated with active energy rays having a specific X-ray diffraction pattern, and this allows for improved adhesion between the substrate layer and other layers such as an ink layer. Furthermore, strength, for example, puncture resistance, can be increased, and flexibility can also be improved.

[0492] Even when the base layer is made of a crystalline material such as polyethylene, the gel fraction does not change compared to before irradiation when the irradiation dose is a low absorbed dose of 100 kGy or less as described above. Thus, it is presumed that the crystallinity of the base layer changes when irradiated with low absorbed doses, but the gel fraction does not change, thereby improving the adhesion, strength, flexibility, etc.

[0493] When the print medium of this embodiment is used for printed matter, it is preferable that the content of the same type of resin (e.g., polyethylene) is 90% by mass or more. In this case, the printed matter can be constructed as a highly recyclable mono-material. Alternatively, even in the case of olefin-based resins, from the perspective of recycling, a mono-olefin configuration may be used in which, for example, the sealant layer 2 contains polyethylene and the base layer 1 contains polypropylene, which are not the same but belong to the olefin-based resin, at 90% by mass or more.

[0494] As described above, the print medium of this embodiment has improved adhesion, strength, etc., and can therefore be suitably used, for example, as the base layer of the first to twelfth embodiments described above.

[0495] <Uses> The print medium of this embodiment is suitable for the printed matter of the first to twelfth embodiments, and can be used for the same purposes as the printed matter 101 of the first embodiment and the printed matter 102 of the second embodiment.

[0496] [Fourteenth embodiment] The fourteenth embodiment is a package formed using the printed matter according to the first to twelfth embodiments. Fig. 13 is a diagram schematically showing an example of a packaged product including the package according to the thirteenth embodiment of the present invention. The packaged product 200 shown in Fig. 13 includes a package 210 and contents (packaged items, not shown) housed therein.

[0497] The packaging body 210 may be, for example, a standing pouch as shown in FIG. 13 . The packaging body 210 can be formed using any of the printed materials 101 to 112 according to the first to twelfth embodiments described above. In this case, the printed materials 101 to 112 according to the first to twelfth embodiments can use the print medium according to the thirteenth embodiment as the base layer. That is, the packaging body 210 can be formed using the print medium according to the thirteenth embodiment. According to the packaging body 210 of this embodiment, because it is formed using the above-mentioned printed material or the above-mentioned print medium, adhesion between the base layer and the active energy ray-curable resin is improved, and peeling or falling off of the active energy ray-curable resin is suppressed.

[0498] Specifically, the package 210 includes a pair of main and bottom films, which are either printed materials described in the first to twelfth embodiments or cut out from them. When the pair of main and bottom films have sealant layers (second to fifth embodiments, seventh to twelfth embodiments), they are overlapped with their sealant layers facing each other, and their peripheral edges are heat-sealed to each other except for one end and its adjacent area. The bottom film is folded in half to form a mountain fold when viewed from the sealant layer side (so that the sealant layer is on the outside), and is sandwiched between the pair of main films at the one end with the mountain fold facing the other end of the main films (the side opposite the one end). The bottom film is heat-sealed to the pair of main films except for its center. The outer surfaces of the bottom films are bonded to each other at both sides of the bottom of the package 210. The package 210 has notches as an easy-open structure where the main films are heat-sealed to each other. The easy-open structure may be provided so that an upper corner can be used as a mouth after opening the packaged product 200. Alternatively, the package 210 may be provided with a mouth member or a lid.

[0499] If the pair of main film and bottom film in the packaging body 210 do not have a sealant layer, adhesive or the like can be used instead of adhesion using a sealant layer, and otherwise the packaging body 210 can be formed in the same manner as when the above-mentioned sealant layer is present.

[0500] Examples of the packaging body 210 include packaging bodies for retort pouches, packaging bodies for boiling, packaging bodies for microwave ovens, packaging bodies for can labels, etc. The packaging body of the present invention is not limited to the above-mentioned stand-up pouch, and can be formed into various other shapes such as a flat pouch, a gusseted pouch with a spout, etc. Furthermore, the shape of the packaging body is not limited to a four-sided bag, and may be, for example, a two-sided bag, a three-sided bag, a gusseted bag, etc.

[0501] The packaged items may be liquids, solids, or mixtures thereof, and examples include foods, medicines, etc. Specific examples include confectioneries such as cookies, rice crackers, etc., foods such as pizza, noodles, soup stock, and coffee, health foods such as supplements, pharmaceuticals, animal foods such as fish food, pet food, and pet treats, vegetable seeds, frozen foods, etc.

[0502] It goes without saying that the configurations of the first to fourteenth embodiments can be used interchangeably as appropriate. Furthermore, the present invention is not limited to the above-described embodiments.

[0503] Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0504] Test Example 1 (Preparation of Printed Material) Example 1 A PET film (manufactured by Unitika Ltd., product name: Emblet PTM, thickness 12 μm) was used as the substrate layer. A predetermined printing was performed on the adhesive layer surface using an offset printing machine (manufactured by COMEXI, CI-8) by wet offset printing with dampening water, using an ink containing an electron beam curable resin. The ink used was an ink containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid. The ink colors used were black (K), cyan (C), magenta (M), yellow (Y), and white (W), as shown in Table 1. In Table 1, "KWW" and similar symbols indicate that the inks were applied in this order from the left to the right, starting from the substrate layer side. As shown in Table 1, multiple samples with different ink colors and ink coverage were prepared. Each ink coverage was adjusted by printing each color over with a solid plate on the offset printing machine. The ink coverage was 100 to 500%.

[0505] After printing, an electron beam (EB) was applied to the ink layer side under a nitrogen atmosphere using an electron beam irradiation device (EC Series, manufactured by ENERGY SCIENCES, INC.) at an exposure dose of 30 kGy. Then, an ink modifier was applied to the cured ink layer using a bar coater device, and the dilution solvent was dried and evaporated at 100 ° C. for 1 minute using an electric dryer (FS-45W, manufactured by Tokyo Glass Equipment Co., Ltd.) to form a modified layer, thereby obtaining the printed matter of Example 1. The ink modifier was prepared by blending an aliphatic polyester polyol (manufactured by Mitsui Chemicals, Inc., trade name: Takelac A626, hereinafter sometimes referred to as "(C)") as the main agent, a polyisocyanate (manufactured by Mitsui Chemicals, Inc., trade name: Takenate A50, hereinafter sometimes referred to as "(D)") as the curing agent, and ethyl acetate as the solvent to prepare an ink modifier with a solids concentration of 36.5% by mass. The blending ratio (by mass) of the components (C):(D) was 8:1. The coating amount of the modified layer was 3.0 g / m ２ was set to.

[0506] Comparative Example 1 A printed matter of Comparative Example 1 was obtained in the same manner as in Example 1, except that no ink modifier was applied onto the ink layer.

[0507] [Evaluation of Adhesion] The printed matter of Example 1 and Comparative Example 1 was held with both hands at a distance of 10 cm and twisted 10 times with both hands, and the presence or absence of ink (ink layer) falling off from the base layer was used as an index of adhesion. Those that did not experience ink falling off were rated A (good), and those that did experience ink falling off were rated B (poor).

[0508]

[0509] In the printed matter of Example 1 having a modified layer, even when an impact was applied to the ink layer, no ink peeling was observed, not only when one color of ink was applied, but also when multiple inks were applied. The reason for this is presumably that the ink modifier penetrates between and into the ink particles in the relatively hard ink layer, thereby improving the adhesion between the ink particles and between the ink particles and the substrate layer. It is also presumed that the ink layer is protected by the relatively soft modified layer containing a urethane-based resin, thereby suppressing cracking of the ink layer.

[0510] In contrast, in the printed matter of Comparative Example 1, which does not have a modified layer, when an impact was applied to the ink layer, no ink came off when one color of ink was applied, but ink came off when multiple inks were applied. The reason for this is presumably that the ink layer hardened by irradiation with an electron beam becomes relatively hard, and as the thickness of the hard ink layer increases, it becomes more difficult for the ink layer to follow the deformation of the base layer.

[0511] Thus, it was shown that the printed matter having the modified layer has improved adhesion and flexibility compared to the printed matter not having the modified layer.

[0512] [Test Example 2] Evaluation of Adhesion Between Substrate Layer and Ink Layer Depending on the Type of Substrate Layer (1) PET film and NY film were used as the substrate layer. Specifically, in Example 2, a PET film (manufactured by Unitika Co., Ltd., product name: Emblet PTM, thickness 12 μm) having an acrylic resin layer as an easy-adhesion layer was used as in Test Example 1, and in Comparative Example 2, a PET film (manufactured by Futamura Corporation, product name: FE2001, 12 μm, the other surface of the PET film being untreated) having a corona-treated surface on one side was used. In Example 3, a NY film (manufactured by Kohjin Film & Chemicals Co., Ltd., product name: Bonyl Q, thickness 15 μm) having an acrylic resin layer as an easy-adhesion layer was used, and in Comparative Example 3, a NY film (manufactured by Kohjin Film & Chemicals Co., Ltd., product name: Bonyl RX, thickness 15 μm) having a corona-treated surface on one side was used. Using an offset printing machine (COMEXI, CI-8), a predetermined printing was performed on the surface of each easy-adhesion layer or the corona-treated surface using an ink containing an electron beam (EB) curable resin by wet offset printing with dampening water. The ink used was an ink containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid. As shown in Table 2, magenta (M) was used as the ink color. As shown in Table 2, laminates (printed materials before EB irradiation) of Examples 2 and 3 and Comparative Examples 2 and 3 were prepared with an ink coverage of 100%. The ink coverage was adjusted by printing each color on top of another using a solid plate on the offset printing machine.

[0513] After printing, the ink layer side was irradiated with an electron beam (EB) at an exposure dose of 45 kGy using an electron beam irradiation device (EC Series, manufactured by ENERGY SCIENCES, INC.) under a nitrogen atmosphere to produce printed matter (printed matter after EB irradiation) of Examples 2 and 3 and Comparative Examples 2 and 3. To evaluate the adhesion of the printed matter of Examples 2 and 3 and Comparative Examples 2 and 3, a cellophane tape peeling test was performed according to the following method.

[0514] [Cellophane tape peeling test] Using a 15 mm wide cellophane tape (manufactured by Nichiban Co., Ltd., product name: Cellotape (registered trademark) CT405AP-15), the adhesive side of the cellophane tape was applied to the surface of each ink layer of the laminates (printed matter before EB irradiation) and printed matter (printed matter after EB irradiation) of Examples 2 and 3 and Comparative Examples 2 and 3, so that the length of the cellophane tape at the adhesive surface with the ink layer was 15 mm or more (i.e., the area of ​​the adhesive surface was 225 mm ２ (= 15 × 15) or more). At this time, an unadhered portion (pulling margin) was left at one end of the length of the cellophane tape to allow the cellophane tape to be pulled. Then, the unadhered portion was grasped with the fingers and peeled off forcefully. After peeling, a region of 15 mm width × 15 mm length (i.e., an area of ​​225 mm) was left on the adhesive surface of the ink layer with the cellophane tape. ２ The ink remaining rate in the area (= 15 × 15) was measured using a metal ruler. The results are shown in Table 2.

[0515]

[0516] As shown in Table 2, the ink remaining rate of the easy-adhesion layer in the substrate layer of Examples 2 and 3 was 0% (all the ink was peeled off) before EB irradiation, but was 100% after EB irradiation, indicating that EB irradiation improves the adhesion between the substrate layer and the ink layer. This suggests that the substrate layers of Examples 2 and 3 (more specifically, the substrate layers including the easy-adhesion layer) have affinity with the electron beam (EB)-curable resin contained in the ink layer, and therefore EB irradiation can improve adhesion to the ink layer. In contrast, the corona-treated surfaces of the substrate layers of Comparative Examples 2 and 3 had an ink remaining rate of 0% before EB irradiation and only 5% after EB irradiation, indicating that EB irradiation does not improve the adhesion between the substrate layer and the ink layer. From this, it is thought that the substrate layers of Comparative Examples 2 and 3 (more specifically, the substrate layers including the corona-treated surface) do not have affinity with the electron beam (EB)-curable resin contained in the ink layer, and therefore, even if EB irradiation is performed, it is not possible to improve adhesion to the ink layer. Note that in Examples 2 and 3, the adhesion between the substrate layer and the ink layer can be further improved by laminating a modified layer on the ink layer. Also in Comparative Examples 2 and 3, the adhesion between the substrate layer and the ink layer can be improved by laminating a modified layer on the ink layer.

[0517] Test Example 3: Evaluation of Adhesion Between Substrate Layer and Ink Layer Depending on the Type of Substrate Layer (2) A PET film was used as the substrate layer. Specifically, in Examples 4 to 6, a PET film having an easy-adhesion layer (manufactured by Unitika Ltd., product name: Emblet PTM, thickness 12 μm) similar to that in Test Example 2 was used. In Comparative Examples 4 to 8 and Example 7, a PET film having one corona-treated surface (manufactured by Futamura Corporation, product name: FE2001, 12 μm, the other surface of the PET film was untreated) similar to that in Test Example 2 was used. Using an offset printing machine (COMEXI, CI-8), a predetermined printing was performed using ink containing an electron beam (EB)-curable resin on the surface of each easy-adhesion layer, the corona-treated surface, or the untreated surface by wet offset printing using dampening water. An ink containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used. As shown in Table 3, magenta (M) was used as the ink color. As shown in Table 3, the ink coverage was set to 100% to produce laminates (printed matter before EB irradiation) for Examples 4 to 7 and Comparative Examples 4 to 8. The ink coverage was adjusted by printing each color over the other using a solid plate on an offset printing press.

[0518] After printing, the printed matter of Examples 4 to 7 and Comparative Examples 4 to 8 was produced by irradiating the ink layer side with an electron beam (EB) in a nitrogen atmosphere using an electron beam irradiation device (EC Series, manufactured by ENERGY SCIENCES, INC.) at the exposure doses (30, 60, 300 kGy) shown in Table 3. To evaluate the adhesion of the printed matter of Examples 4 to 7 and Comparative Examples 4 to 8, a cellophane tape peeling test and a solvent test were carried out according to the following methods.

[0519] [Cellophane Tape Peeling Test] A cellophane tape peeling test was carried out in the same manner as in Test Example 2, and the results were evaluated according to the following criteria.

[0520] <Judgment criteria> A: Ink remaining rate is 95% or more B: Ink remaining rate is 70% or more but less than 95% C: Ink remaining rate is less than 70%

[0521] [Solvent test] Ethyl acetate (Wako Grade 1, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the solvent. A cotton swab was immersed in the solvent and the surface of the ink layer was rubbed twice with the cotton swab. It was visually confirmed whether or not the ink adhered to the cotton swab. If no ink adhered to the cotton swab, the ink removal (detachment of ink from the ink layer) was evaluated as "absent." If ink adhered to the cotton swab, the ink removal (detachment of ink from the ink layer) was evaluated as "present." The results are shown in Table 3.

[0522]

[0523] As shown in Table 3, Examples 4 to 6, which used PET films having the above-described easy-adhesion layer as the substrate layer, achieved a rating of "B" or higher in the cellophane tape peeling test (ink retention rate of 75% or higher) regardless of the EB exposure dose, demonstrating that EB exposure can improve the adhesion between the substrate layer and the ink layer. This suggests that when the substrate layer is a PET film having the above-described easy-adhesion layer, it has high affinity with the electron beam (EB)-curable resin contained in the ink layer regardless of the EB exposure dose. Furthermore, setting the EB exposure dose to 300 kGy or higher not only resulted in no ink removal in the cellophane tape peeling test but also in the solvent test, demonstrating that adhesion can be further improved. When a PET film having a corona-treated surface was used as the substrate layer, forming an ink layer on the corona-treated surface and setting the EB exposure dose to 300 kGy or higher demonstrated no ink removal in the solvent test. From this, it is believed that when the substrate layer is a PET film having a corona-treated surface, setting the EB exposure dose within a specific range when an ink layer is formed on the corona-treated surface will result in affinity with the electron beam (EB)-curable resin contained in the ink layer. Even when the substrate layer has a corona-treated surface, when an ink layer is formed on an untreated surface, as in Comparative Examples 6 to 8, increasing the EB exposure dose to 300 kGy did not improve adhesion in both the cellophane tape peel test and the solvent test. From this, it is believed that when an ink layer is formed on the untreated surface of a substrate layer having an untreated surface and the EB exposure dose is set within a specific range, the affinity with the electron beam-curable resin contained in the ink layer will not be high. In Examples 4 to 7, the adhesion between the substrate layer and the ink layer can be further improved by laminating a modified layer on the ink layer. Also in Comparative Examples 4 to 8, the adhesion between the substrate layer and the ink layer can be improved by laminating a modified layer on the ink layer.

[0524] Test Example 4: Evaluation of Adhesion Between the Substrate Layer and the Ink Layer Depending on the Type of Substrate Layer and Modified Layer PET film and NY film were used as the substrate layer. Specifically, in Examples 8 to 10 and Comparative Examples 9 and 10, a PET film having an easy-adhesion layer similar to that in Test Example 2 (manufactured by Unitika Ltd., product name: Emblet PTM, thickness 12 μm) was used as the PET film. In Examples 11 and 12, an NY film having an acrylic resin layer as the easy-adhesion layer (manufactured by Unitika Ltd., product name: Emblem ONM, thickness 15 μm) was used. Using an offset printing machine (COMEXI, CI-8), a predetermined printing was performed on the surface of each easy-adhesion layer using water-based offset printing with dampening water using an ink containing an electron beam (EB)-curable resin. An ink containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used. The ink colors used were black (K) and white (W), as shown in Table 4. In Table 4, "KWW" and the like indicate that the inks were applied in this order from the base layer side. The ink coverage was adjusted by printing each color in solid ink on an offset printing press. The ink coverage was 300%.

[0525] After printing, the ink layer was irradiated with an electron beam (EB) at a dose of 45 kGy from the ink layer side in a nitrogen atmosphere using an electron beam irradiation device (EC series, manufactured by Energy Sciences, Inc.).

[0526] After EB irradiation, in Example 8, the ink modifier was applied to the cured ink layer using a bar coater, and the dilution solvent was dried and evaporated at 100°C for 1 minute using an electric dryer (FS-45W, manufactured by Tokyo Glass Equipment Co., Ltd.) to form a modified layer. As in Test Example 1, the ink modifier was prepared by blending an aliphatic polyester polyol (manufactured by Mitsui Chemicals, Inc., trade name: Takelac A626, hereinafter sometimes referred to as "(C)") as the base agent, a polyisocyanate (manufactured by Mitsui Chemicals, Inc., trade name: Takenate A50, hereinafter sometimes referred to as "(D)") as the curing agent, and ethyl acetate as the solvent to prepare an ink modifier with a solids concentration of 36.5% by mass. The blending ratio (by mass) of each component was (C):(D) = 8:1. The coating amount of the modified layer was 3.0 g / m ２ Next, an LLDPE film (LL-XMTN, manufactured by Futamura Chemical Co., Ltd.) was laminated (thickness: 70 μm) onto the modified layer as a sealant layer using a laminating device, thereby producing a printed matter of Example 8.

[0527] In Example 9, after EB irradiation, an ink modifier was applied onto the cured ink layer using a bar coater, and the dilution solvent was dried and evaporated at 100°C for 1 minute using an electric dryer (FS-45W, manufactured by Tokyo Glass Equipment Co., Ltd.) to form a modified layer. The ink modifier was prepared by blending and mixing polyether polyol (manufactured by Mitsui Chemicals, Inc., product name: Takelac A953) as the base agent, aromatic polyisocyanate (manufactured by Mitsui Chemicals, Inc., product name: Takenate A93) as the curing agent, and ethyl acetate as the solvent, to prepare an ink modifier with a solids concentration of 33% by mass as a dry lamination resin. The coating amount of the modified layer was 3.0 g / m. ２ Next, in the same manner as in Example 8, an LLDPE film (LL-XMTN, manufactured by Futamura Chemical Co., Ltd.) was laminated (thickness: 70 μm) on the modified layer as a sealant layer to prepare a printed matter of Example 9.

[0528] After EB irradiation, in Comparative Example 9, an adhesive was applied onto the cured ink layer using a bar coater, and then, in the same manner as in Example 8, an LLDPE film (LL-XMTN, manufactured by Futamura Chemical Co., Ltd.) was laminated as a sealant layer, and the resultant was allowed to stand for 24 hours, thereby producing a printed matter of Comparative Example 9.

[0529] In Example 10, after EB irradiation, an ink modifier was applied onto the cured ink layer using a bar coater, and the dilution solvent was dried and evaporated at 100°C for 1 minute using an electric dryer (FS-45W, manufactured by Tokyo Glass Equipment Co., Ltd.), thereby forming a modified layer. The ink modifier was prepared by blending a polybutadiene anchor coat (AC) agent (EL-451, manufactured by Toyo-Morton Co., Ltd.) containing a polybutadiene resin with isopropanol (IPA) and water as solvents, to prepare an ink modifier with a solids concentration of 1.5% by mass. The coating amount of the modified layer was 3.0 g / m ２ Next, extrusion lamination was performed on the modified layer using an extrusion laminator to melt and extrude polyethylene (Novatec LD LC600A, manufactured by Japan Polyethylene Co., Ltd.), thereby forming an extruded resin layer (thickness 20 μm) as a sealant layer, thereby producing the printed matter of Example 10.

[0530] After EB irradiation, in Comparative Example 10, an extruded resin layer (thickness 20 μm) was formed as a sealant layer directly on the cured ink layer without laminating a modified layer or an adhesive layer, in the same manner as in Example 10, thereby producing a printed matter of Comparative Example 10.

[0531] After EB irradiation, in Example 11, a modified layer (the ink modifier used an aliphatic polyester polyol as the main agent and an aromatic polyisocyanate as the curing agent) was laminated on the cured ink layer in the same manner as in Example 8, and an extruded resin layer (Novatec LD LC600A) was laminated on the modified layer as a sealant layer, thereby producing a printed matter of Example 11.

[0532] After EB irradiation, in Example 12, a modified layer (a polybutadiene-based anchor coat (AC) agent containing a polybutadiene-based resin was used as the ink modifier) ​​was laminated on the cured ink layer in the same manner as in Example 10, and an LLDPE film was laminated on the modified layer as a sealant layer to produce the printed matter of Example 12.

[0533] For the printed materials of Examples 8 to 12 and Comparative Examples 9 and 10, a lamination strength test and a lifting test were carried out according to the following methods in order to evaluate the adhesion.

[0534] [Laminate Strength (Adhesion Strength) Test] In accordance with JIS K 6854-2:1999, using a tensile tester (manufactured by Toyo Seiki Seisakusho, product name: Strograph VE10D), the printed matter of Examples 8 to 12 and Comparative Examples 9 and 10 was cut into 15 mm widths to prepare measurement samples, and the interlayer (between the ink layer and the modified layer) at the end of the measurement sample was peeled off. After that, the peel strength was measured under the conditions of an angle of 90 ° (total 180 °), a pulling speed of 300 mm / min, and room temperature, and this peel strength was determined as the adhesive strength at room temperature (20 ° C). The results are shown in Table 4.

[0535] [Measurement of Lifting] The tester held the printed materials of Examples 8 to 12 and Comparative Examples 9 and 10 in both hands, overlapped both hands, and rubbed the printed materials together (once) while moving one hand (for example, the right hand) forward and the other hand (for example, the left hand) backward. Then, the tester rubbed the printed materials together (twice) while moving the right hand backward and the left hand forward. This was repeated 10 times in total to loosen the printed materials. Then, the presence or absence of lifting between the layers of the printed materials was confirmed visually. The results are shown in Table 4.

[0536]

[0537] As shown in Table 4, the printed materials of Examples 8 to 12 had high lamination strength (adhesion strength) and no lifting was observed. This indicates that whether a PET film or a NY film is used as the substrate layer, adhesion can be improved by laminating a modified layer containing a urethane resin or a polybutadiene resin on the substrate layer. This also indicates that the resin layers containing a urethane resin or a polybutadiene resin in Examples 8 to 12 function as modified layers.

[0538] In contrast, the printed matter of Comparative Example 9 had low lamination strength and lifting was also observed. Comparing Comparative Example 9 with Examples 8 to 12, it can be seen that the resin layer (adhesive layer) containing a cyanoacrylate resin does not function as a modified layer. The printed matter of Comparative Example 10 also had low lamination strength and lifting was also observed. Comparing Comparative Example 10 with Examples 8 to 12, it can be seen that the provision of a modified layer can improve the adhesion of the printed matter.

[0539] Test Example 5: Evaluation of suppression of defects when twisting between the substrate layer and the ink layer depending on the type of substrate layer and modified layer Of the printed materials of Examples 8 to 12 that were evaluated as having high adhesion in Test Example 4 above, the printed materials of Examples 8 and 10 to 12 were again subjected to a laminate strength test in the same manner as in Test Example 4 above, and loop stiffness was measured according to the following method, and a pinhole test was also performed to evaluate suppression of defects when twisting. The results are shown in Table 5.

[0540] [Measurement of Loop Stiffness] The printed matter of Examples 8 and 10 to 12 was cut into a rectangular shape of 180 mm x 15 mm to prepare a test piece. Using a loop stiffness measuring instrument (manufactured by Toyo Seiki Seisaku-sho, Ltd., product name: Loop Stiffness Tester DA), the loop stiffness of the test piece in the TD direction was measured under the conditions of a test width of 100 mm, a speed of 3.3 mm / sec, and a time of 3 seconds.

[0541] [Pinhole Test] A Gelbo Flex tester was prepared and used. A printed material measuring 300 mm in length and 200 mm in width was rolled into a cylindrical shape, and the printed material was fixed at both longitudinal ends to the circumferential surface. The test included a pair of 90 mm diameter circular disks, one of which (the fixed circular disk) was fixed so as not to move, and the other (the movable circular disk) was positioned a predetermined distance from the fixed circular disk (the position at which the cylindrical printed material was stretched) (initial position). The tester rotated 440° in one direction (e.g., clockwise) around the central axis from the initial position, approaching the 50 mm fixed circular disk by 150 mm in the longitudinal direction (150 mm from the initial position) (approach position), and then rotated 440° (-440°) in the opposite direction (e.g., counterclockwise) to return to the initial position (allowing for linear bending motion). Of the printed materials of Examples 8 to 12, the printed materials of Examples 8 and 10 to 12 were cut to lengths of 300 mm in length and 200 mm in width. Each printed material was rolled into a cylindrical shape, and both longitudinal ends of the cylindrical printed material were fixed to the circumferential surfaces of a fixed circular disk and a movable circular disk, respectively. The movable circular disk was rotated 440° around its central axis (thereby twisting the printed material) while being moved 150 mm closer to the fixed circular disk to a close position, and then the movable circular disk was rotated 440° (-440°) in the opposite direction from the close position (thereby untwisting the printed material) and moved to the initial position. In this way, the operation of the movable circular disk moving from the initial position to the close position and then returning to the initial position was counted as one operation, and this operation was repeated 1,500 times, after which the presence or absence of pinholes was visually confirmed.

[0542]

[0543] As shown in Table 5, similar to Test Example 4, the printed materials of Examples 8 and 10 to 12 exhibited high adhesion. Furthermore, the greater the loop stiffness in the TD direction of the printed material (the stronger the stiffness), the more likely pinholes tended to occur. In other words, the smaller the loop stiffness in the TD direction of the printed material (the weaker the stiffness), the less likely pinholes tended to occur. Thus, even in printed materials with improved adhesion due to EB irradiation, differences in the strength of the stiffness (loop stiffness) resulted in differences in the incidence of pinhole defects. The mechanism by which such defects occur is thought to be that in printed materials with high loop stiffness, the bent portion is more likely to break at an acute angle when twisted, and this bending causes pinholes and lifting. Furthermore, the hardness of the folded portion makes it more likely for pinholes to occur when rubbed. It was also found that the occurrence of defects such as pinholes can be reduced by EB irradiation of a laminate of an ink layer and a substrate layer having affinity for the ink layer, followed by laminating a modified layer containing a urethane resin. It is also clear that the loop stiffness in the TD direction of the printed matter is preferably 40 or less, more preferably 30 or less, and even more preferably 20 or less.

[0544] [Test Example 6] Evaluation of printing voids (bright spots) The following films were used as the substrate layers. [Substrate layer A] Material rec...

Claims

1. A printing medium suitable for offset printing using an active energy ray curable ink containing an active energy ray curable resin, The substrate layer comprises at least an active energy ray curable resin having affinity for it. The substrate layer, when measured by micro-angle incident X-ray diffraction using a zero-dimensional detector with the 2θ method using CuKα rays, has an X-ray diffraction pattern in which the intensity of the amorphous peak is I0, the intensity of the first peak (110) plane is I1, and the intensity of the second peak (200) plane is I2, is given by the following equation (1): R = (I1+I2) / I0...(1) A printing medium having an intensity ratio R of 2 to 20, as expressed by [formula].

2. The printing medium according to claim 1, wherein the substrate layer is configured to improve adhesion with the active energy ray curable resin by irradiation with an active energy ray having an acceleration voltage of 120 kV or less and an irradiation dose of 25 to 50 kGy.

3. The printing medium according to claim 1 or 2, further comprising a modified layer for modifying the active energy ray curable resin.

4. The printing medium according to claim 3, wherein the modified layer comprises a urethane resin or an acrylic resin.

5. A package formed by the printing medium described in Claim 1 or 2.