Label and label manufacturing method

Abstract

Provided are a label with which it is possible to shield laser printing on the inside of the label from the outside of the label and to clearly confirm laser printing from the inside of the label, and a method for producing the label.　This label (1) comprises a base material (11), an first intermediate layer (13) on the base material (11), a second intermediate layer (14) on the first intermediate layer (13), and a color-developing layer (15) on the second intermediate layer (14). The color-developing layer (15) is capable of exhibiting chromogenic display due to irradiation with a laser beam. The first intermediate layer (13) is capable of shielding chromogenic display in the color-developing layer (15) from the base-material (11) side. The second intermediate layer (14) is capable of heightening the visibility of chromogenic display in the color-developing layer (15) from the color-developing-layer (15) side.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to labels and methods for making labels. [Background technology]

[0002] When printing expiration dates and the like on labels, the mainstream method is to print ink on the surface of the label substrate using, for example, an inkjet printer or a thermal printer.

[0003] However, during transportation of a product to which the label is attached, the ink on the label may be rubbed off, causing the printing to disappear.

[0004] Therefore, there is a demand for printing on labels that will not easily fade once printed. One method that can meet this demand is the laser printing method, which uses laser light to print.

[0005] In the laser marking method, laser marking can be provided on the outer surface of the label by irradiating the label with a laser beam from the outside. There is also a demand for laser marking on the inner surface of the label by irradiating the label with a laser beam from the inside of the label, thereby shielding the laser marking on the inner surface of the label from the outside of the label.

[0006] For example, Patent Document 1 discloses a laser-markable laminated film in which a white ink layer, a printing agent layer, a printed image layer, and a plastic film are laminated in this order from the side irradiated with laser light. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-124499 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the laminated film described in Patent Document 1, the laser markings provided on the inner printing agent layer can sometimes be seen through the outer plastic film of the laminated film. [Means for solving the problem]

[0009] According to the embodiment disclosed herein, a label can be provided which comprises a substrate, a first intermediate layer on the substrate, a second intermediate layer on the first intermediate layer, and a coloring layer on the second intermediate layer, wherein the coloring layer is capable of exhibiting a color display upon irradiation with laser light, the first intermediate layer is capable of blocking the coloring display in the coloring layer from the substrate side, and the second intermediate layer is capable of increasing the visibility of the coloring display in the coloring layer from the coloring layer side.

[0010] According to the embodiment disclosed herein, a method for manufacturing a label can be provided, which includes the steps of forming a first intermediate layer on a substrate, forming a second intermediate layer on the first intermediate layer, forming a color-producing layer on the second intermediate layer, and causing a color display to appear by irradiating laser light onto the color-producing layer, wherein the first intermediate layer is capable of blocking the color display in the color-producing layer from the substrate side, and the second intermediate layer is capable of increasing the visibility of the color display in the color-producing layer from the color-producing layer side. [Effects of the Invention]

[0011] According to the embodiments disclosed herein, it is possible to provide a label and a method for manufacturing the label that can shield the laser printing on the inside of the label from the outside of the label and that allows the laser printing to be clearly visible from the inside of the label. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic cross-sectional view of an example of a label according to an embodiment. [Figure 2] 1 is a histogram showing the absorbance of the labels of Examples 1 to 10. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be described. In the drawings used to describe the embodiments, the same reference numerals denote the same or corresponding parts.

[0014] <label> Figure 1 shows a schematic cross-sectional view of an example of a label according to an embodiment. The label 1 according to the embodiment shown in Figure 1 includes a substrate 11, a design layer 12 on the substrate 11, a first intermediate layer 13 on the design layer 12, a second intermediate layer 14 on the first intermediate layer 13, and a color layer 15 on the second intermediate layer 14. In the label 1 according to the embodiment, the substrate 11 side is the outside, and the color layer 15 is the inside.

[0015] <Base material> The substrate 11 is a plastic film containing a resin capable of supporting at least the first intermediate layer 13, the second intermediate layer 14, and the color-developing layer 15. The plastic film constituting the substrate 11 may be transparent. When the substrate 11 is transparent, the total light transmittance of the substrate 11 is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The total light transmittance is measured according to JIS K 7105 (Testing methods for optical properties of plastics).

[0016] Examples of resins that can be used in the plastic film that constitutes substrate 11 include polyester-based resins (polyethylene terephthalate, polyethylene naphthalate, polylactic acid, etc.), polystyrene-based resins (polystyrene, styrene-butadiene copolymer, etc.), polyolefin-based resins (polyethylene, polypropylene, etc.), polyvinyl chloride-based resins, polyamide-based resins, aramid-based resins, polyimide-based resins, polyphenylene sulfide-based resins, and acrylic-based resins. The plastic film that constitutes substrate 11 may contain one type of these resins, or may contain two or more types.

[0017] The substrate 11 may be, for example, a heat-shrinkable plastic film (shrink film). When the substrate 11 is a shrink film, the label 1 can be attached to the container by, for example, covering the container with the label 1 and then heat-shrinking the substrate 11.

[0018] The substrate 11 may be, for example, a non-heat-shrinkable plastic film. When the substrate 11 is a non-heat-shrinkable plastic film, the label 1 can be used, for example, as a wrap-around label that can be wrapped around the outer surface of a container, a tack label that can be attached to the outer surface of a container, or a flexible packaging bag such as a flat bag, a gusset bag, a pillow bag, or a pouch.

[0019] Substrate 11 may be a single-layer film made of one layer, or a multi-layer film made of two or more layers. The thickness of substrate 11 may be, for example, 5 μm or more and 100 μm or less.

[0020] <First middle class> The first intermediate layer 13 is a layer capable of blocking the color display in the color-producing layer 15 from the side of the substrate 11. In this embodiment, "capable of blocking the color display in the color-producing layer from the side of the substrate" means that even if a color display (laser printing) is not actually formed on the color-producing layer, the color display of the color-producing layer cannot be recognized visually from the side of the substrate, assuming that a color display is actually formed.

[0021] For example, an ink coating containing a color pigment can be used as the first intermediate layer 13. The color pigment of the ink coating constituting the first intermediate layer 13 can be, for example, a single color or a combination of multiple colors such as indigo blue, crimson, yellow, black ink, dark green, silver, gold, or gray. Components other than the color pigment contained in the ink coating constituting the first intermediate layer 13 can include, for example, a binder resin.

[0022] In particular, the first intermediate layer 13 is preferably an ink coating containing a color pigment that has a relatively low transmittance for visible light incident from the substrate 11 side and a relatively low absorbance for laser light incident from the color-forming layer 15 side. Silver, gold, or gray color pigments are preferably used as such color pigments, and silver or gray color pigments are more preferred. In this case, the first intermediate layer 13 can block the color display in the color-forming layer 15 from the substrate 11 side, and can also absorb some of the laser light irradiated from the color-forming layer 15 side, generating heat and helping to form a color display (laser printing) on ​​the color-forming layer 15 side. If the first intermediate layer 13 has too high a transmittance for visible light irradiated from the substrate 11 side, it may not be able to sufficiently block the color display in the color-forming layer 15 from the substrate 11 side. If the absorbance of the laser light irradiated from the color-developing layer 15 side of the first intermediate layer 13 is too high, the amount of laser light absorbed by the first intermediate layer 13 will become too large, and the label 1 may deteriorate due to heat, or the label 1 may melt and form holes in the label 1.

[0023] The absorbance of the laser light (light with a wavelength of 950 nm or more and 1400 nm or less) of the label 1 is preferably greater than 0.22, more preferably greater than 0.24, and particularly preferably greater than 0.40. When the absorbance of the laser light of the label 1 is greater than 0.22, more preferably greater than 0.24, and particularly preferably greater than 0.40, it is possible to block the color display in the color-forming layer 15 from the substrate 11 side, and it is also possible to heat the color-forming layer 15 to a temperature suitable for developing the color display in the color-forming layer 15 by heating with irradiation of the laser light.

[0024] The absorbance of the laser light (wavelength 950 nm or more and 1400 nm or less) of the label 1 is preferably less than 0.92, more preferably 0.6 or less, and particularly preferably 0.55 or less. In these cases, it is possible to block the color display in the color-forming layer 15 from the substrate 11 side, and it is also possible to reduce the possibility that the temperature of the first intermediate layer 13 will become too high due to heating caused by irradiation with the laser light, causing the label 1 to melt.

[0025] The first intermediate layer 13 may have a function of reflecting laser light irradiated from the color-forming layer 15 side. In this case, the laser light irradiated from the color-forming layer 15 side and transmitted through the color-forming layer 15 and the second intermediate layer 14 can be reflected by the first intermediate layer 13 and returned to the color-forming layer 15. This allows the color-forming layer 15 to absorb the reflected laser light and cause the color-forming layer 15 to generate heat again, making it possible to more clearly express the color display.

[0026] <Second middle class> The second intermediate layer 14 is a layer that can improve the visibility of the color display in the color-forming layer 15. In this embodiment, "it is possible to improve the visibility of the color display in the color-forming layer from the color-forming layer side" means that, compared with a case where the label has a second intermediate layer and a case where the label does not have a second intermediate layer, the label has the property of allowing the color display formed in the color-forming layer to be more clearly recognized by visual observation from the color-forming layer side of the label when the label has a second intermediate layer.

[0027] For example, an ink coating containing a color pigment can be used as the second intermediate layer 14. The color pigment of the ink coating constituting the second intermediate layer 14 can be, for example, a pale color such as pale yellow or pale pink, or white. Components other than the color pigment contained in the ink coating constituting the second intermediate layer 14 can include, for example, a binder resin.

[0028] In particular, it is preferable to use an ink coating containing a color pigment that can improve the visibility of the color display in the color-forming layer 15 from the color-forming layer 15 side as the second intermediate layer 14. For example, a white solid ink layer can be used as such a second intermediate layer 14. In particular, when a QR code (registered trademark) or a barcode is to be displayed on the color-forming layer 15, it is preferable that the second intermediate layer 14 be a white solid ink layer.

[0029] <Coloring layer> The color-producing layer 15 is a layer that can produce a color display when irradiated with laser light. In this embodiment, "capable of producing a color display when irradiated with laser light" means that even if the color-producing layer 15 is not actually irradiated with laser light, the color-producing layer 15 has the property of producing a color (discoloration) at a location irradiated with laser light, assuming that the color-producing layer 15 is actually irradiated with laser light.

[0030] As the color-forming layer 15, any color-forming coating film capable of exhibiting a color display upon irradiation with laser light can be used without any particular limitation. A color-forming coating film containing a leuco dye that can change color upon irradiation with laser light can be used as the color-forming layer 15. For example, the color-forming layer 15 can be a layer that is transparent before irradiation with laser light, turns black when heated at the irradiated portion, and the blackened portion displays a color.

[0031] <Design Layer> The design layer 12 is a layer that has a design that is visible from the substrate 11 side. For example, as shown in FIG. 1 , the design layer 12 can be positioned between the substrate 11 and the first intermediate layer 13 of the label 1, but is not limited to this. Furthermore, the label 1 does not necessarily have to have a design layer 12.

[0032] The design layer 12 can be a layer that can suppress heat generation due to irradiation with laser light. If the design layer 12 is a layer that can suppress heat generation due to irradiation with laser light, the possibility of the design layer 12 absorbing the laser light and generating heat, which will cause the label 1 to melt, can be reduced.

[0033] In order to make the design layer 12 a layer that can suppress heat generation due to irradiation with laser light, it is preferable that the design layer 12 contain a pigment that can suppress absorption of laser light. For example, if carbon black is used as the pigment that constitutes the design layer 12 to express black in the design layer 12, the design layer 12 may generate too much heat when irradiated with laser light, so it is preferable to mix a pigment that has low absorption in the wavelength range of laser light (for example, yellow, indigo, or crimson) instead of carbon black to achieve a black color.

[0034] <Other layers> The label 1 may further include other layers. The positions and materials of the other layers are not particularly limited, but examples thereof include a color ink layer, or a protective layer such as a medium for protecting the label 1 from external factors on the outside of the substrate 11 (the side opposite to the side on which the first intermediate layer 13 is located) or on the inside of the color-forming layer 15 (the side opposite to the side on which the second intermediate layer 14 is located).

[0035] <Label manufacturing method> The label 1 of the embodiment can be manufactured, for example, as follows: First, a step of preparing the substrate 11 is carried out. The step of preparing the substrate 11 can be carried out, for example, by forming a plastic film by a method such as an extrusion method or a calendar method, and, if necessary, by further subjecting the plastic film to a stretching treatment.

[0036] Next, a step of forming a first intermediate layer 13 is carried out on the surface of the substrate 11. The step of forming the first intermediate layer 13 can be carried out, for example, by applying an ink resin composition for the first intermediate layer, which is a precursor of the ink coating film that constitutes the first intermediate layer 13, onto the surface of the substrate 11 and then drying it.

[0037] When the label 1 has a design layer 12 between the substrate 11 and the first intermediate layer 13, a step of forming the design layer 12 on the surface of the substrate 11 is carried out. The step of forming the design layer 12 can be carried out, for example, by printing an ink resin composition that serves as a precursor of the design layer 12 by gravure printing, flexographic printing, inkjet printing, screen printing, or offset printing.

[0038] Next, a step is performed to form the second intermediate layer 14 on the surface of the first intermediate layer 13. The step of forming the second intermediate layer 14 can be performed, for example, by applying an ink resin composition for the second intermediate layer, which is a precursor of the ink coating film that constitutes the second intermediate layer 14, onto the surface of the substrate 11 and then drying it.

[0039] Next, a step is carried out to form the color-forming layer 15 on the surface of the second intermediate layer 14. The step of forming the color-forming layer 15 can be carried out, for example, by applying a color-forming coating film resin composition, which serves as a precursor of the color-forming coating film that constitutes the color-forming layer 15, onto the surface of the second intermediate layer 14 and then drying it.

[0040] In this way, the label 1 of the embodiment can be manufactured. The label 1 of the embodiment includes a first intermediate layer 13 between the substrate 11 and the color-forming layer 15, which is capable of blocking the color display in the color-forming layer 15 from the substrate 11 side. Therefore, in the label 1 of the embodiment, the color display in the color-forming layer 15 is blocked, i.e., cannot be visually confirmed, from the substrate 11 side.

[0041] Furthermore, the label 1 of the embodiment includes a second intermediate layer 14 between the first intermediate layer 13 and the coloring layer 15, which can improve the visibility of the color display in the coloring layer 15 from the coloring layer 15 side. Therefore, in the label 1 of the embodiment, the color display in the coloring layer 15 can be clearly confirmed visually from the coloring layer 15 side.

[0042] Therefore, in the label 1 of the embodiment, it is possible to shield the laser printing on the inside of the label 1 from the outside of the label 1, and the laser printing can be clearly seen from the inside of the label 1. [Example]

[0043] <Preparation of Label of Example 1> First, a substrate made of a 45 μm thick transparent polystyrene film was prepared. Next, a first intermediate layer ink resin composition containing a silver color pigment was applied to one surface of the substrate and then dried to form a silver first intermediate layer having a thickness of 3 to 5 μm.

[0044] Next, an ink resin composition for a second intermediate layer containing a white coloring pigment was applied to one surface of the substrate on the surface of the first intermediate layer on which the substrate was not formed, and then dried to form a white second intermediate layer consisting of a white solid ink layer with a thickness of 3 to 5 μm.

[0045] Next, a resin composition for a color-forming coating film, which serves as a precursor to the color-forming coating film that constitutes the color-forming layer, was applied to the surface of the second intermediate layer on the side on which the first intermediate layer was not formed, and then dried to form a transparent color-forming layer.

[0046] Thereafter, a transparent medium was applied to the surface of the color-forming layer on the side on which the second intermediate layer was not formed, thereby producing the label of Example 1.

[0047] <Preparation of Label of Example 2> The label of Example 2 was produced using the same method and conditions as Example 1, except that a 3 to 5 μm thick indigo color ink layer was formed between the substrate and the first intermediate layer and the first intermediate layer was silver.

[0048] <Preparation of Label of Example 3> A label of Example 3 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was gold in color.

[0049] <Preparation of Label in Example 4> A label of Example 4 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was colored gray.

[0050] <Production of Label of Comparative Example 1> A label of Comparative Example 1 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was indigo blue.

[0051] <Production of Label of Comparative Example 2> A label of Comparative Example 2 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was colored red.

[0052] <Production of Label of Comparative Example 3> A label of Comparative Example 3 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was colored yellow.

[0053] <Production of Label of Comparative Example 4> A label of Comparative Example 4 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was black. Note that black ink using carbon black was used as the material for the black first intermediate layer.

[0054] <Production of Label of Comparative Example 5> A label of Comparative Example 5 was produced in the same manner and under the same conditions as in Example 1, except that the first intermediate layer was not formed.

[0055] <Absorbance measurement> The labels of Examples 1 to 4 and Comparative Examples 1 to 5 were placed on a white table with the substrate facing up (exposed side). Near-infrared light with a wavelength of 950 nm was then irradiated from the substrate side at an angle to the labels, and the absorbance of each of the labels of Examples 1 to 4 and Comparative Examples 1 to 5 was calculated from the intensity of the reflected light from each of the labels of Examples 1 to 4 and Comparative Examples 1 to 5. The results are shown in Tables 1, 2, and FIG. 2. The values ​​in the "Absorbance" column in Tables 1 and 2 indicate the absorbance of the labels of Examples 1 to 4 and Comparative Examples 1 to 5.

[0056] <Redissolving ink> After the above-mentioned near-infrared irradiation, the appearance of the labels of Examples 1 to 4 and Comparative Examples 1 to 5 was evaluated visually. The results are shown in Tables 1 and 2. In the "ink redissolution" column of Tables 1 and 2, "Yes" indicates that ink bleed-through of the layers constituting the label was confirmed, and "No" indicates that ink bleed-through of the layers constituting the label was not confirmed.

[0057] <Printing visibility> The color-forming layer of each of the labels of Examples 1 to 4 and Comparative Examples 1 to 5 was irradiated with near-infrared light at a wavelength of 950 nm from the color-forming layer side to form a laser print, and then the visibility of the laser print from the color-forming layer side of the label was visually evaluated according to the following criteria A to C. The results are shown in Tables 1 and 2. In the "Visibility of Laser Printing" column of Tables 1 and 2, "A" indicates that the laser print (black) was clearly visible due to the contrast with the second intermediate layer (white), "B" indicates that the laser print was visible due to the contrast with the second intermediate layer, and "C" indicates that the laser print was not sufficiently visible even in contrast with the second intermediate layer.

[0058] <Shielding property> The color-forming layer of each of the labels of Examples 1 to 4 and Comparative Examples 1 to 5 was irradiated with near-infrared light at a wavelength of 950 nm from the color-forming layer side to form a laser print, and then the shielding ability of the laser print from the substrate side of the label was visually evaluated according to the following criteria A to C. The results are shown in Tables 1 and 2. In the "Shielding ability" column of Tables 1 and 2, "A" indicates that the laser print was completely shielded by the first intermediate layer, "B" indicates that the laser print was almost completely shielded by the first intermediate layer, and "C" indicates that the laser print was not sufficiently shielded by the first intermediate layer.

[0059] [Table 1]

[0060] [Table 2]

[0061] <Evaluation> As shown in Tables 1 and 2, it was confirmed that the labels of Examples 1 to 4 were superior to the labels of Comparative Examples 1 to 5 in both the shielding properties of laser marking due to the first intermediate layer and the visibility of laser marking due to the second intermediate layer.

[0062] It was also confirmed that the labels of Examples 1 to 4, which have an absorbance greater than 0.22 and less than 0.55, particularly greater than 0.24 and less than 0.55, can improve both the shielding properties of laser marking by the first intermediate layer and the visibility of laser marking by the second intermediate layer, compared to the labels of Comparative Examples 1 to 5, which have an absorbance of 0.22 or less.

[0063] It was also confirmed that the labels of Examples 1, 2, and 4, which have an absorbance of 0.40 or more and 0.55 or less, can improve both the shielding properties of laser marking by the first intermediate layer and the visibility of laser marking by the second intermediate layer, compared to the label of Example 3, which has an absorbance of 0.24.

[0064] Although the embodiments and examples have been described above, it is originally intended that the configurations of the above-described embodiments and examples may be appropriately combined.

[0065] The embodiments and examples disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] 1 label, 11 substrate, 12 design layer, 13 first intermediate layer, 14 second intermediate layer, 15 color layer.

Claims

1. A transparent substrate; a silver, gold, or gray first intermediate layer on the substrate; a white second intermediate layer on the first intermediate layer; a color-forming layer on the second intermediate layer and in contact with the second intermediate layer, the color-producing layer is capable of exhibiting a color display when irradiated with a laser beam having a wavelength of 950 nm or more and 1400 nm or less; the first intermediate layer is capable of blocking the color display in the color-producing layer from the base material side; The second intermediate layer can enhance visibility of the color display in the color-forming layer from the color-forming layer side, The label can be attached to a container by heat-shrinking the substrate after placing the label on the container, or is a wrap-around label that can be wrapped around the outer surface of a container.

2. The label of claim 1 , wherein the absorbance of the laser light of the label is greater than 0.22 and less than 0.

92.

3. The label according to claim 1 or 2, further comprising a design layer between the substrate and the first intermediate layer, the design layer being visible from the substrate side.

4. A step of forming a silver, gold, or gray first intermediate layer on a transparent substrate; forming a white second intermediate layer on the first intermediate layer; forming a color-forming layer on the second intermediate layer so as to be in contact with the second intermediate layer; and a step of irradiating the color-producing layer with laser light having a wavelength of 950 nm or more and 1400 nm or less to produce a color display, the first intermediate layer is capable of blocking the color display in the color-producing layer from the base material side; The second intermediate layer can improve visibility of the color display in the color layer from the color layer side, A label manufacturing method in which the label can be attached to a container by covering the container with the label and then heat-shrinking the substrate, or the label is a wrap-around label that can be wrapped around the outer surface of a container.

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