Laminated packaging material for liquid foods, method for manufacturing the same, method for printing thereon, and packaging container manufactured therefrom.

Abstract

A laminated packaging material (1) for liquid food, comprising a core layer (4) of paper or paperboard or other cellulosic material, a laminate portion (3) disposed on a first side of the core layer (4), and a dark flexographic printing ink composition (2) printed on a free surface of the laminate portion (3), wherein the dark ink composition comprises color bases mixed in a ratio such that the total energy absorption of the dark flexographic printing ink composition (2) when printed on the laminated packaging material (1) is less than 80%, for example less than 70%, in an emission spectrum from a tungsten light source within a range of 250 to 2500 nm at a temperature of 3000 K, and the dark flexographic printing ink composition (2) has a black color of L * It has a color space brightness of ≦25 and a color space difference (ΔE2000) of 6 or less.

Description

Technical Field

[0001] The present invention relates to a laminated packaging material, more specifically, a laminated packaging material containing an ink composition such as a dark ink composition.

Background Art

[0002] Currently, various techniques are used to print graphics such as decorative patterns and / or characters on laminated packaging materials for liquid foods. Most of them require various methods of applying ink by rotary printing on a moving web of the packaging material to print static content. The content to be printed is pressed onto the laminated material by a stereotype roller and then dried or cured to remove all water or solvents. A typical such printing technique is flexographic printing using an aqueous ink composition. Therefore, when printing a large surface area of the laminated packaging material, a large investment is required to manufacture and manage a large printing station / press that covers all of the laminated material to be printed. Further, when manufacturing the laminated material at high throughput, further requirements for equipment are demanded, such as the positioning of printing graphics of other features on the material web, such as different colors and linear wrinkles, at a high web speed. An economical web speed requires rapid drying / curing of the ink to avoid bleeding or soiling of the ink when advancing the printed surface to the next operation or when winding the packaging material into a roll. Another aspect of rotary printing technology is that it requires personnel to prepare different printing plates for different products or customer content, and changing the various printing plates is time-consuming. When printing by flexographic printing, the most understandable method is to observe the raster and the minimum dots.

[0003] To address some of these challenges, alternative or additional printing solutions are being considered, such as printing dynamic content using inkjet or similar digital technologies. Because the printing technologies are entirely different, different types of ink are required to carry out the printing operation. In inkjet printing, droplets of ink are formed and dropped onto the surface to be printed. Such inks must contain a larger amount of water for printing compared to inks used in web printing technologies. Inkjet-printed areas are detected by observing the print resolution, and furthermore, the dots are not perfectly aligned in high-speed printing.

[0004] Therefore, when combining printing static graphics using pressure printing technology with digital printing for dynamic content, problems can arise with the laminated packaging material when drying the ink due to the different water content of the inks used in the different technologies. The typical appearance of printed areas using flexographic and inkjet printing is known to those skilled in the art. [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to overcome at least partially one or more of the above-mentioned limitations of the prior art. In particular, the object is to provide an ink composition such as a dark ink composition for packaged laminates that reduces the risk of defects in the laminate while the ink is curing in the printing process. [Means for solving the problem]

[0006] The laminate is positioned on a first side of a core layer of paper, cardboard, or other cellulosic material. The laminate includes at least one layer of a polymer, such as a thermoplastic polymer (such as a polyolefin polymer). The polyolefin polymer layer may be an extruded coating or an extruded laminated layer, or a separately manufactured polyolefin film, which may be oriented in at least one direction. The polyolefin polymer may be selected from the group consisting of polyethylene, polypropylene, blends thereof, and copolymers mainly containing ethylene and / or propylene. Alternatively, the laminate may include a pre-manufactured polymer film containing PET (polyethylene terephthalate) or other thermoplastic polyester. The laminate may further include a layer of adhesive or adhesive polymer. The pre-manufactured film may further include a barrier coating (such as a metallized coating) or a holographic pattern.

[0007] The laminated portion can therefore be printed using various printing techniques to obtain graphic patterns of static and / or dynamic content. Once laminated, the printed graphics are applied to the free surface outside the laminated portion and bonded to the core layer.

[0008] An ink composition containing a pigment, i.e., a color base, for imparting color patterns such as dark patterns, may further contain a binder, such as a polymer or oligomer binder, a solvent, such as water, and further additives and resins. While the amounts of these binders, solvents, additives, and resins may vary, it should be understood that the color base described herein, i.e., a CMYK or GVCMYK color base, provides a favorable ratio and amount for the relevant advantages described. The color base may contain coloring pigments, such as CMYK or GVCMYK coloring pigments, as described herein. However, the color base may optionally or additionally contain other coloring compounds, such as dye ink colors.

[0009] Percentages in this disclosure are expressed as mass percentages unless otherwise specified.

[0010] The laminated portion includes at least one polymer layer that may be susceptible to high heat loads, such as during drying. Typical heat-sensitive polymer layers are polyolefins such as polyethylene, polypropylene, blends and copolymers thereof. Typically, the laminated portion may also include a film of an oriented polymer, such as the pre-fabricated film described above, which has been coated with an attractive coating to improve the appearance of packaging containers made of the laminated material. Examples of such films include metallized uniaxial or biaxially oriented polypropylene films (OPP, BOPP), or holographic polymer films based on oriented polyolefins such as OPP or BOPP. Alternatively, such films may be oriented high-density polyethylene films (OHDPE, BOHDPE). Polyester films such as oriented polyethylene terephthalate (OPET, BOPET) can also be used for the metallized or holographic films.

[0011] By providing an additional liquid-tight polymer on the surface of the printed laminated portion, i.e., the surface facing outward from the packaging container made from the laminated packaging material, the material can be made suitable for packaging liquid foods. Such a liquid-tight polymer may be a thermoplastic polymer layer that forms the outer surface of the packaging container and further makes the outside of the packaging container heat-sealable.

[0012] The core layer may be paper, cardboard, or other cellulosic material, and it provides bulk properties and stability to the laminate. This type of large internal layer can provide bending stiffness and dimensional stability through its own contribution. Alternatively, it can contribute to the overall bending stiffness and flexural rigidity of the laminate by combining it with a sandwich structure having opposing layers on one or both sides that have a higher Young's modulus than the large core layer itself. The core layer, due to its cellulose content, can provide some degree of independent thermal barrier, allowing directly adjacent polymers to withstand high temperatures well.

[0013] Further laminated portions, including additional polymer layers, barrier layers or coatings, paper sheets, foils, etc., may be applied to the second side portion, i.e., the interior of the core layer.

[0014] Laminated packaging materials for packaging liquid foods include at least one innermost liquid-tight, heat-sealable polymer layer made of a thermoplastic material such as polyolefin. Suitable polyolefins for the innermost layer are polyethylene, polypropylene, or copolymers thereof. Particularly preferred are low-density polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (e.g., including one or more of so-called linear low-density polyethylene (LLDPE), metallocene-LLDPE (mLLDPE), ultra-low-density polyethylene (ULDPE), and very low-density polyethylene (VLDPE)) and blends thereof. Between the core layer and the innermost layer, there may be further material layers providing oxygen barriers and other barrier properties, such as aluminum foil, polymer-derived layers with gas barrier properties, barrier coating films, such as metallized films or vapor-deposited coating films. Common and suitable gas barrier polymers include, for example, ethylene and vinyl alcohol (EVOH) polyamides or polymers. Further barrier or stabilizing layers (such as additional paper sheets) may be added between the core layer and the innermost layer.

[0015] According to a first embodiment, a laminated packaging material for liquid food is provided, comprising a core layer of paper, cardboard, or other cellulosic material having first and second sides, the second side being opposite to the first side; a laminated portion disposed on the first side of the core layer of paper, cardboard, or other cellulosic material; and a dark flexographic printing ink composition printed on the free surface of the laminated portion and covering at least partially the free surface, wherein the dark flexographic printing ink composition comprises a color base mixed in such a ratio that the total energy absorption rate by the dark flexographic printing ink composition when supplied onto the laminated packaging material is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K, and the dark flexographic printing ink composition is L* Having a color space lightness of ≤25, the dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black reference composition, and the black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It has a value of =0.

[0016] A system for producing a laminated packaging material for liquid food is provided, comprising: a drying unit for drying a packaging material having a core layer of paper, cardboard, or other cellulosic material having first and second sides, the second side being opposite to the first side, and a laminated portion disposed on the first side of the core layer of paper, cardboard, or other cellulosic material; and a printing unit for printing a dark flexographic printing ink composition onto the free surface of the laminated portion to at least partially cover the free surface, wherein the dark flexographic printing ink composition comprises a color base mixed in such a ratio that the total energy absorption rate by the dark flexographic printing ink composition when printed on the laminated packaging material is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K of a tungsten light source, wherein the dark flexographic printing ink composition comprises L * Having a color space lightness of ≤25, the dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black reference composition, and the black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It has a value of =0.

[0017] According to a third aspect, a method of printing on a laminated packaging material for liquid foods is provided. This method includes a step of forming a core layer of paper or paperboard or other cellulosic material having a first and a second side portion, the second side portion being on the opposite side of the first side portion, and a step of disposing a laminated portion on the first side portion of the core layer of paper or paperboard or other cellulosic material. This method includes a step of printing a dark flexographic printing ink composition on the free surface of the laminated portion to at least partially cover the free surface, where the dark flexographic printing ink composition has a total energy absorption rate by the dark flexographic printing ink composition when printed on the laminated packaging material of less than 80%, for example less than 70%, in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K of the tungsten light source, and includes a color base mixed in such a ratio, where the dark flexographic printing ink composition has an L * color space lightness of ≦25, the dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to a black reference composition, and the black reference composition has a lightness L * = 17, a red-green component a * = 0, and a blue-yellow component b * = 0.

[0018] According to a fourth aspect, a method of manufacturing a packaging container for liquid foods is provided, the method including a step of forming a packaging material for liquid foods according to the first aspect and a step of folding the packaging material into at least a partially completed packaging container.

[0019] A liquid food packaging container is provided, comprising a core layer of paper, cardboard, or other cellulosic material having first and second sides, the second side being opposite to the first side; a laminated portion disposed on the first side of the core layer of paper, cardboard, or other cellulosic material; and a dark flexographic printing ink composition printed on the free surface of the laminated portion and at least partially covering the free surface, wherein the dark flexographic printing ink composition comprises a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition when supplied onto the laminated packaging material is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K of a tungsten light source, wherein the dark flexographic printing ink composition comprises L * Having a color space lightness of ≤25, the dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black reference composition, and the black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It has a value of =0.

[0020] Further embodiments of the present invention are defined in the dependent claims, and features of the first embodiment may be implemented in the second and subsequent embodiments, and vice versa.

[0021] Having a dark flexographic printing ink composition that includes a color base mixed in a ratio such that the total energy absorption rate is less than 80%, for example less than 70%, and the color space values ​​are as described above, the temperature of the laminate decreases during the drying process, thereby reducing the risk of defects in the laminate while still allowing the ink composition to print dark colors on the laminate.

[0022] Throughout this disclosure, the term "laminate" should be understood to mean a multilayer structure which may include individual layers of polymers, adhesives, polymer films, paper sheets, layers having gas barrier properties or other barrier properties, and coatings. The individual layers are typically bonded to each other across the entire interface of each layer, and so each layer completely covers the area of ​​the laminate.

[0023] Further other objects, features, embodiments, and advantages of the present invention will become apparent from the description and drawings detailed below.

[0024] Herein, embodiments of the present invention will be described as examples with reference to the attached schematic drawings. [Brief explanation of the drawing]

[0025] [Figure 1a] This is a cross-sectional view of a laminated packaging material for packaging liquid foods, comprising a printed dark ink composition. [Figure 1b] This is a cross-sectional view of a laminated packaging material for packaging liquid foods, comprising a printed dark ink composition. [Figure 1c] This is a cross-sectional view of a laminated packaging material for packaging liquid foods, comprising a printed dark ink composition. [Figure 2] This is a cross-sectional view of a laminated packaging material for packaging liquid food products, comprising a printed dark ink composition, and laminated on both sides. [Figure 3] This is a cross-sectional view of a system for manufacturing a laminated packaging material for packaging liquid foods, comprising a dark-colored ink composition. [Figure 4a] A flowchart illustrating a method for printing on laminated packaging material for liquid food packaging is provided. [Figure 4b] A flowchart illustrating a method for printing on laminated packaging material for liquid food packaging is provided. [Figure 5] A flowchart illustrating a method for manufacturing a packaging container for a laminated packaging material for packaging liquid foods, containing a dark-colored ink composition, is provided. [Figure 6]This is a perspective view of a packaging container manufactured from a laminated packaging material for packaging liquid foods, containing a dark-colored ink composition. [Figure 7a] This is a schematic diagram showing the change in the shear modulus (G) with respect to temperature (T) within the laminated portion. [Figure 7b] This is a schematic diagram showing a regression analysis of the temperature value (T) in the layered portion versus the amount (%) of black (K) color base in the ink composition. [Figure 8] These figures show the softening of the laminated portions before and after applying energy to a dark ink composition (Figures 8a-8b) and a control composition containing 45% black pigment (K) (Figures 8c-8d). [Figure 9] Examples of printing at various manufacturing speeds (a) 600, (b) 330, (c) 270, (d) 240, and (e) 220 (m / min) are shown, along with the changes in the amount of curing energy absorbed by the associated ink composition. [Figure 10] This figure shows the emission spectrum (E) from a tungsten light source and the absorption rate of the corresponding dark ink composition. [Modes for carrying out the invention]

[0026] Referring to Figure 1a, an example of a laminated packaging material 1 for liquid food is illustrated. The laminated packaging material 1 includes a core layer 4 made of paper, cardboard, or other cellulosic material having a first side and a second side. The second side is on the opposite side of the first side of the core layer 4 made of paper, cardboard, or other cellulosic material, and constitutes the inside of the laminated packaging material 1, facing directly inward to the packaging container 10 made of the laminated packaging material 1. The laminated packaging material 1 further includes a laminated portion 3 positioned on the first side of the core layer 4, facing outward to the packaging container 10 made of the laminated packaging material 1. A dark ink composition 2 is printed on the free surface of the laminated portion 3. Thus, the dark ink composition 2 covers the free surface at least partially with the printed pattern. The dark ink composition 2 is a flexographic printing ink composition, i.e., an ink composition printed by flexographic printing.

[0027] The dark ink composition 2 includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition when applied on the laminated packaging material 1 is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250-2500 nm at a temperature of 3000 K. Absorptance can be described here as the effectiveness of the surface material in absorbing radiance energy in the spectrum of 250 nm-2500 nm. Figure 10 shows the emission spectrum (E) from a tungsten light source. The corresponding absorption rates (%) of the dark flexographic printing ink composition 2 when printed on the laminated packaging material 1 are shown, for example, by curves A1 and A2. Curve A1 is obtained from a sample of laminated packaging material 1 having a transparent coating or layer containing a thermoplastic polymer on the dark flexographic printing ink composition 2, for example, schematically illustrated in Figure 1c. The A2 curve is obtained from a sample of laminated packaging material 1 without a transparent coating or layer containing a thermoplastic polymer on the dark flexographic printing ink composition 2, as schematically illustrated in Figure 1a. The results for the two types of packaging material 1 are equivalent. The total energy absorption rate by the dark flexographic printing ink composition 2 of the radiance energy in the 250 nm to 2500 nm range is less than 80% for both A1 and A2, e.g., less than 70%, and is essentially equally well below 80%, e.g., less than 70%.

[0028] The absorption rate of a black body is 100% of its radiance energy. Figure 10 shows a black control ink containing 80% conventional black color base (K) that absorbs approximately 89% of the same spectrum on average.

[0029] In this manner, the color base in the dark ink composition 2 is mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition 2 becomes less than 80%, for example, less than 70%, as described above.

[0030] The laminated packaging material 1 may contain one or more dark flexographic printing ink compositions 2 on the free surface of the laminated portion 3. The color bases in each of these one or more dark flexographic printing ink compositions 2 are mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink compositions 2 is less than 80%, for example, less than 70%, as described above. Therefore, all flexographic printing ink compositions present in the laminated packaging material may have a total energy absorption rate of less than 80%, for example, less than 70%, in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K.

[0031] Preparation for the experiment to measure absorption rate Absorbance was calculated based on the reflectance spectrum measured using a Perkin Elmer Lambda 1050 UV-VIS-NIR spectrophotometer equipped with an integrating sphere. Pressed Eastman Kodak BaSO4 was used as a reflectance reference. Absorbance was calculated using the reflectance spectrum from 250 to 2500 nm. The photodetector was located inside the sphere and protected from direct light by a baffle. The geometric arrangement used was non-directional illumination at an angle of 8°, i.e., incident light reaching the surface being inspected at an angle of 8° to the perpendicular to the surface. The specular portion of the reflected light could be removed by removing a portion of the sphere's wall that struck all specularly reflected light. The Wolfram spectrum was used as a weighting function in the calculation. The optical method for absorbance was carried out according to SS-EN ISO 22975-3:2015 Part 5 and its references. This method was modified based on the conversion from solar spectra to Wolfram lamp spectra in determining absorbance.

[0032] The integrated value of total reflectance and diffuse reflectance ρ s (Total) and ρ s (Diffuse) was calculated according to the following formula 1. ρ s (Total or Diffuse)=∫S(λ)ρ(λ)dλ2500nmλ=250nm / ∫S(λ)dλ2500nmλ=250nm (Formula 1) During the ceremony, S(λ) is the Wolfram spectrum, ρ(λ) is the reflectance spectrum (total reflection or diffuse reflection), λ is the wavelength, ρ s (Specular) is given by the following equation 2 ρ s (Total) = ρ s (Specular) + ρ s (Diffuse) (Equation 2) Calculated according to, In the formula, ρ s (Total) and ρ s (Diffuse) is defined by equation 1 above and calculated according to equation 1 above. The specularity is ρ s (Specular) / ρ s It is defined as (Total), The absorption rate is α s = 1 - ρ s It is calculated as follows.

[0033] The obtained spectrum ρ s Based on (λ) and equations 1 and 2, the absorbance (α) corresponding to the total absorptance above s The following was calculated, but this is less than 80% for dark ink composition 2, for example, less than 70%.

[0034] The dark flexographic printing ink composition 2, which includes a color base mixed in a ratio such that the total energy absorption rate is less than 80%, for example less than 70%, lowers the temperature of the laminated portion 3 under high heat load, such as during the drying process, because drying is typically achieved by using an NIR dryer having an emission spectrum corresponding to or overlapping with the emission spectrum (E) in Figure 10. The amount of energy absorbed by the ink composition may correlate with the temperature achieved by the ink composition 2; that is, an increase in absorbed energy also raises the temperature. Therefore, the reduced energy absorption rate of the ink composition 2 when heated or passed through a dryer lowers the maximum temperature of the ink composition 2, and thereby lowers the maximum temperature of the laminated portion 3 due to thermal contact with each other. The reduced temperature reduces the risk of defects in the laminated portion 3. The total energy absorption rate of the prior ink composition or the control ink composition is greater than 70%, for example, greater than 80%, of the radiance energy in the emission spectrum of 250 nm to 2500 nm and the measurement method described above, as illustrated in Figure 8d, and causes softening of the laminated portion 3, as will be discussed further below.

[0035] Therefore, the energy absorption rate of the dark ink composition 2 in the infrared spectrum (E) is lower than the energy required to initiate softening of the laminated portion 3. By controlling the energy distribution, the laminated portion 3 is prevented from undergoing undesirable, irreversible structural changes. For example, when a string of characters is printed, the string of characters maintains its intended shape. This is particularly advantageous when printing patterns intended for data readout, such as QR codes®, barcodes, or other patterns for data readout that are often printed by digital printing technologies such as inkjet. Figures 9a to 9e show examples of such patterns, i.e., QR patterns (including enlarged views in the right column). As described above, having a color base in the dark flexographic printing ink composition 2, with a total energy absorption rate of less than 80%, e.g., less than 70%, and mixed in a ratio that prevents softening, also makes it possible to use any additional clearly printed patterns for data readout, corresponding to the pattern seen in Figure 9a, in combination with exposure to high thermal loads. On the other hand, Figures 9b to 9e illustrate a situation in which softening of the laminated portion 3 occurs due to increased energy absorption, which is typically observed when using the preceding dark flexographic printing ink. The same applies when different graphics, such as logos or photographs, are printed. Therefore, a decrease in energy absorption rate is advantageous when the printed packaging material is exposed to high heat, for example, during drying by infrared irradiation, which may be necessary when combining different printing technologies. For example, when printing features with inkjet printing, it may be necessary to expose the laminated packaging material 1 to increased drying at near-infrared wavelengths; otherwise, softening of the laminated portion 3 is likely to occur. Static patterns (i.e., the same for all packaging containers) can be printed using the dark ink composition 2 in the flexographic printing process, but dynamic patterns such as variable QR codes are expected to be printed by inkjet printing. Therefore, the energy required to dry the inkjet-printed pattern does not affect the integrity of the laminated portion 3 due to the reduced energy absorption rate mentioned above.This also applies when inkjet-printed features are printed with different ink compositions, because the dark ink composition 2 supplied by flexographic printing sufficiently reduces the energy absorption rate and the temperature of the laminated portion 3.

[0036] The energy absorption rate of the dark ink composition 2 is ≤80% and / or within the range of 805nm to 960nm ≤74% and / or within the range of 960nm to 1162nm ≤67% and / or within the range of 1162nm to 1422nm ≤59% and / or within the range of 1422nm to 1868nm ≤51% within the range of 1868nm to 2263nm That's fine.

[0037] The dark flexographic printing ink composition 2 has a color space lightness L * It has a value of ≤25. Brightness L * is, a * and b * The values ​​(for the green-red and blue-yellow components, respectively) are standard measures in the "CIELAB" color space. * a * b * The color space is a three-dimensional real number space. Brightness L * L * =0 represents the darkest black, L * =100 represents the brightest white. Color channel a * and b * is, a * =0 and b * =0 represents the true achromatic intensity value. * The axis represents the green-red component, with green indicating the negative direction and red indicating the positive direction. * The axis represents the blue-yellow component, with blue being the negative direction and yellow being the positive direction. Therefore, the dark flexographic printing ink composition 2 is L *It contains a color base mixed in a ratio of 25 or less. This gives a particularly favorable dark contrast pattern while still having a total energy absorption rate of less than 80%, for example less than 70%. * Dark inks having ≤25 exhibit an energy absorption rate that softens the laminated portion 3, as described in relation to Figures 8d and 9a-9e. Dark contrast patterns are particularly desirable for data reading such as barcodes or for printed strings. Furthermore, in various printing designs with various layouts and colors, the energy absorption rate is minimized while still providing desired color characteristics, such as saturation, hue, and contrast. This means that the dark ink composition 2 may include color bases mixed in various combinations to provide different colors for different applications, and at the same time, the mixture has a ratio of color bases such that the total energy absorption rate of the dark ink composition 2 is lower than the energy required to soften the laminated portion 3 in the infrared spectrum.

[0038] Furthermore, the dark flexographic printing ink composition 2 has a color space difference (ΔE2000) of 6 or less with respect to the black reference composition. The color space difference is a standard in the CILAB color space for quantifying the difference between two colors, and the "ΔE2000" standard is currently the most widely used. The black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It is specified that it has = 0. Therefore, dark flexographic printing ink composition 2 contains a color base mixed in a ratio such that the color space difference (ΔE2000) is ≤ 6 with respect to the black reference composition. The above lightness (L * The ink composition 2 provides a particularly advantageous dark contrast pattern on the laminated packaging material 1, while still avoiding the risk of softening the laminated portion 3 due to a reduction in the energy absorption rate by the ink composition 2, such that ) is ≤ 25.

[0039] Dark ink composition 2 can achieve the color space values ​​specified above and a total energy absorption rate of less than 80%, for example, less than 70%, by mixing a number of different color bases. In some examples, the amount of black color base (K) is adjusted to a minimum value, and at the same time the amounts of other color bases (e.g., GVCMYK color bases) are changed to obtain dark ink composition 2 having desired color characteristics, such as saturation, hue, contrast, etc. Table 1 below shows examples of different color base compositions (1-3) in dark ink composition 2 (including varnish (TV) and extender (Ext)) as percentages of the total composition.

[0040] [Table 1]

[0041] The compositions in Table 1 have the following color space values ​​(1) L * =20.9, a * =0.4, b * =0.2, (2)L * =22.2, a * =0.5, b * =0.3, (3)L * =22.8, a * =0.3, b * It has a value of =0.4.

[0042] The total energy absorption rate for each composition in Table 1 is less than 80% of the radiance energy in the emission spectrum (E), for example, less than 70%.

[0043] These ratios can produce a particularly advantageous dark flexographic printing ink composition 2 with optimized color characteristics and further improved resistance to temperature rise due to IR energy absorption. The pigments of the color base GVCMYK can be mixed with a dispersible pigment medium to transport the pigments to the substrate. The pigment medium may include varnish and fillers as shown in Table 1. The fillers or extenders increase the area covered by a given mass of pigment.

[0044] Although ink composition 2 has been described as a dark ink composition in the embodiments of this disclosure, it should be understood that a wide variety of dark colors can be produced by changing the amounts of each color base in ink composition 2. Therefore, for example, by applying a favorable ratio of black color base (K), a wide range of dark colors can be achieved with ink composition 2 while maintaining an energy absorption rate below the softening threshold and the associated temperature rise. * a * b * The type of color base in the color space may vary depending on the optimization for various applications. In one embodiment, the color base includes the following types of pigments: green 7, violet 23, blue 15:3 (phthalocyanine blue PB15), magenta 57.1 (lythol rubin PR), yellow 74, and black 7. The pigments in this disclosure are supplied by Siegwerk. Various variants may be used, while still providing the advantages associated with the color base ratios described in this disclosure, as described above. Pigment (K) black 7 is a carbon pigment dispersed in water, particularly lightfast.

[0045] It should be understood that the above-described ink compositions having a certain ratio of color bases include the case where either color base is present in zero amount in the mixture. The color bases are mixed in such a ratio that the energy absorption rate of the dark ink composition is equal to or lower than the energy required to soften the layered portion in the infrared spectrum.

[0046] In one embodiment illustrated in Figure 7a, when the laminated portion 3 contains LDPE, softening of the laminated portion 3 occurs at 325-375K, more specifically at 360K (indicated as T1 in Figure 7a), meaning that the shear modulus (G) decreases significantly at temperature T1. In another embodiment, also shown in Figure 7a, when the laminated portion 3 contains BoPP, softening of the laminated portion 3 occurs at 420-460K, more specifically at 440K.

[0047] In some embodiments, as illustrated in Table 1, the dark ink composition 2 contains up to 12% K, i.e., black color base (Siegwerk). Having up to 12% K controls the energy absorption rate of the dark ink composition 2 so that the maximum temperature of the dark ink composition 2 is achieved before the laminated portion 3 reaches its softening temperature. Figure 7b shows a regression analysis of the temperature value in the laminated portion (LDPE) 3 versus the amount (%) of black (K) color base in the ink composition 2. As shown in the figure, with 12% K, the black color base (K) mentioned above... t By having a limit value of ), the temperature rise due to IR absorption can be kept at a lower temperature than T1, when the shear modulus (G) decreases and softening occurs. Therefore, the energy required to soften the laminated portion 3 corresponds to the energy absorbed at T1. Figure 8 shows the results for ink composition 2 containing 12% black color base (K) (Figures 8a-8b) and a control composition containing more than 12% black color base (K), at 47 kJ / m 2 This figure shows the visible effect of softening of the laminated portion 3 when applied. The maximum amount of black color base depends largely on the content of black pigments containing or presenting carbon, such as so-called "carbon black." The carbon black content can vary among various black color bases and among black color bases from different ink manufacturers. Figures 8a and 8c show the laminated portion 3 before energy absorption, and Figures 8b and 8d show the laminated portion 3 after energy absorption. Significant softening occurred in the laminated portion 3 of the control composition (Figure 8d), but ink composition 2 absorbed lower energy and maintained the integrity of the laminated portion 3 (Figure 8b).

[0048] The ratio of the color base in ink composition 3 can be determined in part depending on the particle size of the pigment used in the color base, so that the energy absorption rate of the comparative ink composition is equal to or lower than the energy required to soften the laminated portion in the infrared spectrum. Therefore, the ratio can be adjusted depending on the particle size of the pigment. Thus, it should be understood that the ratio described herein can vary depending on the size of the pigment particles while still giving the advantageous properties described for ink composition 3. Smaller pigment particle sizes can result in higher saturation, brightness, and color gamut. The amount of black (K) color base in ink composition 3 can be further reduced while still giving the desired color properties such as those described above, while simultaneously further minimizing the amount of energy absorbed and assuming a rise in temperature during IR curing.

[0049] In another embodiment, the maximum percentage of K that can be used is further or alternatively based on the thickness of the laminated portion 3.

[0050] In one embodiment, the dark ink composition 2 is a flexographic printing ink composition. Using the dark flexographic printing ink composition 2, it is possible to print on many types of substrates (including plastics, metal films, cellophane, and paper), for example, on packaging for liquid foods. It is also well suitable for printing large areas of plain material. In one embodiment, the dark flexographic printing ink composition 2 is an aqueous ink. The use of aqueous ink is more environmentally friendly.

[0051] In one embodiment, the dark flexographic printing ink composition 2 contains a red-green component in the color space ranging from -4.6 to +4.6 (a * ) has a blue-yellow component (b) in the range of -7 to +7 in the color space. * ) is also present. The color space difference (ΔE2000) of the dark flexographic printing ink composition 2 with respect to the black control composition described above may be 6 or less in this embodiment.

[0052] In further embodiments, the dark flexographic printing ink composition 2 contains a red-green component in the color space ranging from -3.0 to +3.0 (a* ) may have a blue-yellow component (b) in the range of -4.4 to +4.4 in the color space. * ) may have. This provides particularly advantageous color characteristics and enables the realization of an ink composition 2 that can be used in a wide range of applications with different print designs using different layouts and colors.

[0053] The color space difference (ΔE2000) of the dark flexographic printing ink composition 2 with respect to the black contrast composition described above may be 4 or less. This allows for an even darker ink composition 2 in the color space, which is advantageous for several contrast patterns in different print designs.

[0054] Referring to Figure 1a, the laminated portion 3 may include a thermoplastic polymer layer containing a polymer such as polyolefin (e.g., polyethylene, for example, low-density polyethylene and / or linear low-density polyethylene (LLDPE, mLLDPE, ULDPE, VLDPE, etc.)). Examples of polyethylenes other than low-density polyethylene include high-density and medium-density polyethylene (HDPE, MDPE). The dark ink composition 2 may be printed directly onto the thermoplastic polymer layer.

[0055] The laminated portion 3 may include the pre-fabricated polymer film described above. Referring to Figure 1b, the laminated portion 3 may also include a pre-fabricated polymer film 3'' laminated on the first side of the core layer 4, where a second laminated layer 3' containing a thermoplastic polymer adheres the pre-fabricated polymer film 3'' to the first side of the core layer 4. The dark ink composition 2 can be printed on the pre-fabricated polymer film 3''.

[0056] The second laminated layer 3' and the thermoplastic polymer may include low-density polyethylene (LDPE) and / or linear low-density polyethylene (including LLDPE, mLLDPE, ULDPE, and VLDPE).

[0057] An additional layer 5 containing a thermoplastic polymer such as polyolefin or polyethylene, for example low-density polyethylene (LDPE) and / or linear low-density polyethylene (including LLDPE, mLLDPE, ULDPE, and VLDPE), can be placed on the dark ink composition 2, as schematically illustrated in Figure 1c. The energy absorption rate may, again, be measured as described with respect to Figure 10 above.

[0058] The second side of the core layer 4 may be laminated onto an inner layer 6 of a liquid-tight thermoplastic polymer, as schematically illustrated in Figure 2. The inner layer is intended to come into contact with liquid food. This provides complementary protection for the core layer 4, such as gas, mechanical, or liquid protection.

[0059] The packaging material 1 may include the inkjet-printed feature 7 described above. The inkjet-printed feature 7 may be printed on the laminated portion 3, as shown in the dark ink composition 2 in Figures 1a and 1b. Figure 1a is a schematic diagram showing the inkjet-printed feature 7 on the laminated portion 3. The schematic diagram in Figure 1a also shows an example where the inkjet-printed feature 7 covers the dark ink composition 2. Alternatively, or in addition, the inkjet-printed feature 7 may be printed on an additional layer 5, as illustrated in the embodiment of Figure 1c.

[0060] In addition to the dark ink composition 2 described as dark flexographic printing ink composition 2 in the embodiments of this disclosure, it should be understood that in some embodiments, further printed features, graphics, or patterns may be printed with an even darker ink composition using a digital printing technique such as inkjet printing. Flexographic printing can be distinguished from inkjet printing by observing the minimum dot size of the raster and printed features. For example, by observing the print resolution, if the dots are not perfectly aligned when printed at high speed, it can be identified as inkjet printing. Also, the overall coverage can appear to vary greatly depending on the printing method. The visual differences between flexographic printing and inkjet printing should be obvious to those skilled in the art and can be distinguished and determined from each other by the eye of those skilled in the art.

[0061] In one embodiment, the laminated portion 3 includes a metallized film or a holographic film. By using different types of such decorative, colored, or treated films together with a dark ink composition in the laminated portion 4, a variety of different effects and patterns can be given.

[0062] A system 20 for manufacturing a laminated packaging material 1 for liquid food is illustrated in Figure 3. The system 20 includes a drying unit 30 for drying the packaging material 1, which has first and second sides, with the second side being opposite the first side of the core layer 4. As described, the laminated portion 2 is placed on the first side of the core layer 4 of paper, cardboard, or other cellulosic material 4. The system 20 includes a printing unit 25 for printing a dark flexographic printing ink composition 2 onto the free surface of the laminated portion 3 to at least partially cover the free surface. The dark flexographic printing ink composition 2 includes a color base mixed in such a ratio that the total energy absorption rate by the dark flexographic printing ink composition 2 is less than 80%, e.g., less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250-2500 nm at a tungsten light source temperature of 3000 K when printed on the laminated packaging material 1. The dark flexographic printing ink composition 2 has a color space lightness L *It has a color space difference (ΔE2000) of ≤25 and 6 or less with respect to the black reference composition. The black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It has a value of =0.

[0063] Therefore, system 20 offers the above-mentioned advantages to the laminated packaging material 1 shown in Figures 1, 2, 7 to 10.

[0064] In one embodiment, the drying unit 30 heats or dries the packaging material 1 using near-infrared wavelengths. In one embodiment, the energy of the near-infrared wavelength is 5 to 80 kJ / m 2 For example, 20-60 kJ / m³ 2 For example, 35-55 kJ / m³ 2 For example, 45-49 kJ / m³ 2 It is within the range.

[0065] In one embodiment, the near-infrared wavelength is in the range of 250 to 2500 nm, more specifically, 800 to 1500 nm.

[0066] The system 20 may include an inkjet printing unit 26, as schematically illustrated in Figure 3. The inkjet printing unit 26 can arrange inkjet-printed features 7 on the laminated packaging material 1, as schematically illustrated in Figures 1a and 1c.

[0067] In one embodiment, the system 20 operates at a manufacturing speed of at least 100 m / min, 200 m / min, 300 m / min, 400 m / min, 500 m / min, or most preferably 600 m / min. Figures 9a to 9e show examples of printing at different speeds (a) 600, (b) 330, (c) 270, (d) 240, and (e) 220 (m / min). As the speed increases, the amount of energy absorbed decreases, and therefore the amount of defects decreases.

[0068] Figure 4a is a flowchart of a method 50 for printing on a laminated packaging material 1 for liquid food, which includes a step 60 of forming a core layer 4 of paper, cardboard, or other cellulosic material having first and second sides, the second side being opposite to the first side of the core layer 4, and the laminate 3 being placed on the first side of the core layer 4. Method 50 includes a step 70 of printing a dark flexographic printing ink composition 2 onto the free surface of the laminate portion 3 to at least partially cover the free surface. The dark flexographic printing ink composition 2 includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition 2 when printed on the laminated packaging material 1 is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition 2 has a color space lightness L * It has a color space difference (ΔE2000) of ≤25 and 6 or less with respect to the black reference composition. The black reference composition has a lightness L in the color space. * =17, red-green component a * = 0, and the blue-yellow component b * It has = 0. Therefore, method 50 provides the above-mentioned advantageous benefits for the laminated packaging material 1 of Figures 1, 2, 7 to 10.

[0069] In one embodiment, all the color bases in the dark ink composition 2 are mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition 2 is less than 80%, for example, less than 70%, as described above.

[0070] Method 50 may include a step 70 of printing one or more dark flexographic printing ink compositions 2 onto the free surface of the laminated portion 3. The entire color bases of each of the one or more dark flexographic printing ink compositions 2 may be mixed in a ratio such that the total energy absorption rate of the dark flexographic printing ink compositions 2 is less than 80%, for example, less than 70%. Thus, all flexographic printing ink compositions present in the laminated packaging material may have a total energy absorption rate of less than 80%, for example, less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K.

[0071] Figure 4b is a further flowchart of method 50 for printing on a laminated packaging material for liquid foods. Method 50 may further include step 80 for printing inkjet-printed features 7 on the laminated portion 3 as described above. Method 50 may also include step 90 for applying an additional layer 5 of thermoplastic polymer on the dark flexographic printing ink composition 2, as schematically illustrated in Figure 1c. The additional layer 5 of thermoplastic polymer can be applied by extrusion coating.

[0072] In one embodiment, method 50 may include the step of applying a second laminated portion 6, which includes at least one further laminate on the second side of the core layer 4, as schematically illustrated in Figure 2. In a further embodiment, method 50 may include, in addition to or instead of the step of inkjet printing on the laminated portion 3 as described above, the step of printing the inkjet-printed features 7 on an additional layer 5 of thermoplastic polymer, in a step 80.

[0073] In one embodiment, method 50 further includes step 100 of drying the feature 7 that has been inkjet printed with near-infrared wavelength. In one embodiment, the energy of the near-infrared wavelength is 5 to 80 kJ / m 2 For example, 20-60 kJ / m³ 2 For example, 35-55 kJ / m³ 2 For example, 45-49 kJ / m³ 2 It is within the range.

[0074] In one embodiment, the manufacturing speed is at least 100 m / min, 200 m / min, 300 m / min, 400 m / min, 500 m / min, or most preferably 600 m / min.

[0075] In one embodiment, as schematically illustrated in Figure 6, a method 200 for manufacturing a liquid food packaging container 10 is provided, comprising the steps of: forming a liquid food packaging material 1 having the above-mentioned flexographic printing ink composition 2 based on Figures 1, 2, 7 to 10; and folding the packaging material 1 into at least a partially complete packaging container 10, a method 220. The partially complete packaging container 10 is a packaging container that can hold at least liquid food by being folded and sealed. The packaging container 10 does not need to be completely airtight to prevent leakage of liquid food. For example, an opening device such as a cap or opening can be applied later. Alternatively, for example, the packaging container 10 may need to be folded into a final packaging container 10, with one side of the packaging container 10 still sealed.

[0076] In this way, a liquid food packaging container 10 is also provided. The liquid food packaging container 10 includes a core layer 4 made of paper, cardboard, or other cellulosic material, having first and second sides, the second side being opposite the first side of the core layer 4. The liquid food packaging container 10 further includes a laminated portion 3, which is positioned on the first side of the core layer 4. The dark flexographic printing ink composition 2 is printed on the free surface of the laminated portion 3, covering this free surface at least partially. When the dark flexographic printing ink composition 2 is placed on the laminated packaging material 1, it includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition 2 is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition 2 has a color space lightness L * It has a color space difference (ΔE2000) of ≤25 and 6 or less with respect to the black reference composition. The black reference composition has a lightness L in the color space.* = 17, red - green component a * = 0, and blue - yellow component b * = 0. Therefore, the packaging container 10 for liquid food provides the above - mentioned advantageous advantages for the laminated packaging material 1 in FIGS. 1, 2, 7 - 10.

[0077] In other embodiments, since the packaging container 10 for liquid food is made from the laminated packaging material 1, it has the same features and corresponding effects as described above.

[0078] From the above description, various embodiments of the present invention have been described and shown. However, the present invention is not limited to these, and it is also possible to be embodied in other ways within the scope of the subject matter defined in the following claims.

Explanation of reference numerals

[0079] 1 Laminated packaging material 2 Dark - color flexographic printing ink composition 3 Laminated portion 3’ Second laminated layer 3’’ Pre - manufactured polymer film 4 Core layer 5 Additional layer 6 Inner layer of liquid - tight thermoplastic polymer 7 Ink - jet printed feature 10 Packaging container for liquid food 20 System 25 Printing unit 26 Ink - jet printing unit 30 Drying unit 50 Printing method

Claims

1. A core layer (4) of paper, cardboard, or other cellulosic material having first and second sides, wherein the second side is on the opposite side of the first side of the core layer of paper, cardboard, or other cellulosic material, A laminated portion (3) disposed on a first side of the core layer of paper, cardboard, or other cellulose-based material, wherein the laminated portion comprises a first surface located on the core layer side and a free surface located on the opposite side of the first surface. A dark flexographic printing ink composition (2) is printed on the free surface of the laminated portion and at least partially covers the free surface. A laminated packaging material (1) for liquid food containing, When the dark flexographic printing ink composition is provided on the free surface of the laminated portion, it includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition has a color space lightness L ＊ ≤25, In the color space, the red-green component (a) is in the range of -4.6 to +4.

6. ＊ ), The blue-yellow component (b) in the range of -7 to +7 in the color space ＊ ), and A color space difference (ΔE2000) of 6 or less relative to the black control composition. It has, The black contrast composition is in the color space, Brightness L ＊ =17、 Red-green component a ＊ = 0, and Greenish-yellow component b ＊ =0 A laminated packaging material for liquid foods having the following properties.

2. A packaging material for liquid food according to claim 1, wherein the color space difference (ΔE2000) is 4 or less.

3. The dark flexographic printing ink composition contains a red-green component (a) in the color space ranging from -3.0 to +3.

0. ＊ ) has a blue-yellow component (b) in the color space in the range of -4.4 to +4.

4. ＊ A liquid food packaging material according to claim 1 or 2, having the following characteristics:

4. The liquid food packaging material according to any one of claims 1 to 3, wherein the laminated portion comprises a thermoplastic polymer layer, for example, polyolefin, for example, polyethylene, for example, low-density polyethylene and / or linear low-density polyethylene.

5. The liquid food packaging material according to any one of claims 1 to 4, wherein the laminated portion includes a polymer film manufactured in advance.

6. The liquid food packaging material according to any one of claims 1 to 5, wherein the laminated portion includes a pre-fabricated polymer film (3'') laminated on the first side of the core layer, and a second laminated layer (3'') containing a thermoplastic polymer adheres the pre-fabricated polymer film to the first side of the core layer.

7. The liquid food packaging material according to claim 6, wherein the second laminated layer and the thermoplastic polymer include low-density polyethylene and / or linear low-density polyethylene.

8. The liquid food packaging material according to any one of claims 1 to 7, wherein the second side of the core layer is laminated to an inner layer (6) of a liquid-tight thermoplastic polymer, and the inner layer is intended to come into contact with food.

9. A liquid food packaging material according to any one of claims 1 to 8, comprising a feature (7) inkjet printed on the free surface of the laminated portion (3) and / or on the dark flexographic printing ink composition (2).

10. The liquid food packaging material according to any one of claims 1 to 9, wherein the laminated portion includes a metallized polymer film or a holographic polymer film.

11. A drying unit (30) for drying a packaging material having a laminated portion (3) disposed on the first side of a core layer of paper, cardboard, or other cellulosic material, wherein the laminated portion comprises a first surface located on the core layer side and a free surface located on the opposite side of the first surface. A printing unit (25) that prints a dark flexographic printing ink composition onto the free surface of the laminated portion to cover at least a portion of the free surface, A system (20) for manufacturing a laminated packaging material (1) for liquid food containing, The dark flexographic printing ink composition includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition when printed on the free surface of the laminated portion is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition has a color space lightness L ＊ ≦ 25 In the color space, the red-green component (a) is in the range of -4.6 to +4.

6. ＊ ), and The blue-yellow component (b) in the range of -7 to +7 in the color space ＊ ) It has, The dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black control composition. The black contrast composition is in the color space, Brightness L ＊ =17、 Red-green component a ＊ = 0, and Greenish-yellow component b ＊ =0 Having, A system for manufacturing laminated packaging materials for liquid foods.

12. The system for producing laminated packaging material for liquid food according to claim 11, wherein the drying unit dries the packaging material using near-infrared wavelengths.

13. The energy of the aforementioned near-infrared wavelength is 5 to 80 kJ / m ２ For example, 20-60 kJ / m ２ For example, 35-55 kJ / m ２ For example, 45-49 kJ / m ２ A system for manufacturing a laminated packaging material for liquid food according to claim 11 or 12, which is within the range of the specified range.

14. A system for manufacturing a laminated packaging material for liquid food according to any one of claims 11 to 13, comprising an additional inkjet printing unit (26).

15. A step (60) of providing a core layer (4) of paper, cardboard, or other cellulosic material having first and second sides, wherein the second side is on the opposite side of the first side of the core layer of paper, cardboard, or other cellulosic material, and the laminated portion (3) is disposed on the first side of the core layer of paper, cardboard, or other cellulosic material, and the laminated portion comprises a first surface located on the core layer side and a free surface located on the opposite side of the first surface. A printing step (70) to print a dark flexographic printing ink composition onto the free surface of the laminated portion to at least partially cover the free surface. A method (50) of printing on a laminated packaging material for liquid food containing, The dark flexographic printing ink composition includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition when printed on the free surface of the laminated portion is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition has a color space lightness L ＊ ≤25, In the color space, the red-green component (a) is in the range of -4.6 to +4.

6. ＊ ), and The blue-yellow component (b) in the range of -7 to +7 in the color space ＊ ) It has, The dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black control composition. The black contrast composition is in the color space, Brightness L ＊ =17、 Red-green component a ＊ = 0, and Greenish-yellow component b ＊ =0 Having, A method for printing on laminated packaging material for liquid foods.

16. A method for printing on a laminated packaging material for liquid food according to claim 15, comprising the step (80) of printing an inkjet-printed feature (7) on the free surface of the laminated portion (3) and / or on the dark flexographic printing ink composition (2).

17. A method for printing on a laminated packaging material for liquid food according to claim 16, comprising the step (100) of drying the inkjet-printed features with near-infrared wavelength.

18. A method for printing on a laminated packaging material for liquid food according to any one of claims 15 to 17, wherein the manufacturing speed is at least 100 m / min, 200 m / min, 300 m / min, 400 m / min, 500 m / min, or most preferably 600 m / min.

19. A core layer (4) made of paper, cardboard, or other cellulose-based material, having first and second sides, wherein the second side is on the opposite side of the first core layer made of paper, cardboard, or other cellulose-based material, A laminated portion (3) disposed on a first side of the core layer of paper, cardboard, or other cellulose-based material, wherein the laminated portion comprises a first surface located on the core layer side and a free surface located on the opposite side of the first surface. A dark flexographic printing ink composition (2) is printed on the free surface of the laminated portion and at least partially covers the free surface. A liquid food packaging container (10) containing, The dark flexographic printing ink composition includes a color base mixed in such a ratio that the total energy absorption rate of the dark flexographic printing ink composition when applied to the free surface of the laminated portion is less than 80%, for example less than 70%, of the radiance energy in the emission spectrum from a tungsten light source in the range of 250 to 2500 nm at a temperature of 3000 K. The dark flexographic printing ink composition has a color space lightness L ＊ ≤25, In the color space, the red-green component (a) is in the range of -4.6 to +4.

6. ＊ ), and The blue-yellow component (b) in the range of -7 to +7 in the color space ＊ ) It has, The dark flexographic printing ink composition has a color space difference (ΔE2000) of 6 or less with respect to the black control composition. The black contrast composition is in the color space, Brightness L ＊ =17、 Red-green component a ＊ = 0, and Greenish-yellow component b ＊ =0 Having, Packaging containers for liquid foods.

20. The liquid food packaging container according to claim 19, comprising a feature (7) inkjet printed on the free surface of the laminated portion (3) and / or on the dark flexographic printing ink composition (2).

21. The dark flexographic printing ink composition (2) includes static content, which is a decorative pattern, text string, pattern intended for data reading, logo, or photograph. The laminated packaging material for liquid food according to claim 1.

22. The dark flexographic printing ink composition (2) includes static content, which is a decorative pattern, text string, pattern intended for data reading, logo, or photograph. A system for manufacturing a laminated packaging material for liquid food according to claim 11.

23. The dark flexographic printing ink composition (2) includes static content, which is a decorative pattern, text string, pattern intended for data reading, logo, or photograph. A method for printing on a laminated packaging material for liquid food according to claim 15.

24. The dark flexographic printing ink composition (2) includes static content, which is a decorative pattern, text string, pattern intended for data reading, logo, or photograph. A packaging container for liquid food according to claim 19.

25. The laminated portion comprises an inkjet-printed feature (7) on the free surface of the laminated portion and / or on the dark flexographic printing ink composition (2), or on an additional layer (5) containing a thermoplastic polymer provided on the laminated portion. The aforementioned feature includes dynamic content, Laminated packaging material for liquid food according to claim 1 or 21.

26. The laminated portion comprises an inkjet-printed feature (7) on the free surface of the laminated portion and / or on the dark flexographic printing ink composition (2), or on an additional layer (5) containing a thermoplastic polymer provided on the laminated portion. The aforementioned feature includes dynamic content, A system for manufacturing a laminated packaging material for liquid food according to claim 11 or 25.

27. The process includes steps (80, 90) of printing an inkjet-printed feature (7) onto the free surface of the laminated portion and / or onto the dark flexographic printing ink composition (2), or onto an additional layer (5) containing a thermoplastic polymer provided on the laminated portion. The aforementioned feature includes dynamic content, A method for printing on a laminated packaging material for liquid food according to claim 15 or 23.

28. The laminated portion comprises an inkjet-printed feature (7) on the free surface of the laminated portion and / or on the dark flexographic printing ink composition (2), or on an additional layer (5) containing a thermoplastic polymer provided on the laminated portion. The aforementioned feature includes dynamic content, A packaging container for liquid food according to claim 19 or 24.

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