JP2023146722A - Laminate production method - Google Patents

Abstract

To provide a laminate production method capable of achieving variable printing in which expression properties has been enhanced.SOLUTION: There is provided a production method of a laminate 20 comprising: a step S1 for preparing a laminate precursor 10 including a substrate 11, and an inorganic flake-containing ink layer 13 on the substrate 11; and a step S2 for radiating an energy ray 15 to the laminate precursor 10. The inorganic flake-containing ink layer 13 includes inorganic flake. In the step for radiating the energy ray 15, a direction of the inorganic flake on a position where the energy ray 15 is radiated is varied.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a method for manufacturing a laminate.

When printing an expiration date or the like on a label, the mainstream method is to print ink on the surface of the label base material using, for example, an inkjet printer or a thermal printer.

However, when the product to which the label is attached is transported, the print may disappear due to rubbing of the ink on the label.

Therefore, with regard to printing on labels, there is a demand for printing that is difficult to erase once printed. As one method to meet this demand, a laser printing method in which printing is performed by irradiating laser light is being considered.

In the laser printing method, laser printing can be provided on the outer surface of the label by irradiating the label with laser light from the outside. There is also a demand for providing laser printing on the inner surface of the label by irradiating laser light from inside the label and shielding the laser printing on the inner side of the label so that it cannot be seen from the outside of the label.

For example, Patent Document 1 describes a laminated film for laser printing in which a white ink layer, a printing agent layer, a printed pattern layer, and a plastic film are laminated in this order from the side to which the laser beam is irradiated. discloses a method of printing on a laminated film by irradiating a laser from the opposite side.

JP 2017-124499 Publication

In the method described in Patent Document 1, the printing agent layer is colored black by irradiation with laser light, thereby printing, and the printing becomes visible due to the contrast between the blackened resin part and the non-blackened resin part. It has become. The method described in Patent Document 1 is an excellent method that allows variable printing (printing contents can be changed) such as QR code (registered trademark) and random number printing. However, in the method described in Patent Document 1, the only expressiveness of printing is color change due to temperature increase, and the expressiveness of printing is insufficient when used for decoration purposes.

According to the embodiment disclosed herein, the steps include: preparing a laminate precursor including a base material and an ink layer containing inorganic flakes on the base material; and irradiating the laminate precursor with energy rays. The ink layer containing inorganic flakes contains inorganic flakes, and in the step of irradiating energy rays, it is possible to provide a method for manufacturing a laminate in which the direction of the inorganic flakes at the location irradiated with energy rays changes.

According to the embodiment disclosed herein, it is possible to provide a method for manufacturing a laminate that allows variable printing with improved expressivity compared to the method described in Patent Document 1.

It is a flow chart of a manufacturing method of a layered product of an embodiment. FIG. 2 is a schematic cross-sectional view of an example of a laminate precursor used in the laminate manufacturing method of the embodiment. FIG. 3 is a schematic cross-sectional view illustrating an example of a step of irradiating the laminate precursor shown in FIG. 2 with energy rays. FIG. 2 is a schematic plan view of a laminate manufactured by the laminate manufacturing method of the embodiment, as viewed from the base material side. FIG. 5 is a schematic plan view when the base material of the laminate shown in FIG. 4 is viewed from the base material side after being heat-shrinked. FIG. 7 is a schematic cross-sectional view illustrating another example of the step of irradiating the laminate precursor with energy rays.

Embodiments will be described below. Note that in the drawings used to describe the embodiments, the same reference numerals represent the same or corresponding parts.

FIG. 1 shows a flowchart of a method for manufacturing a laminate according to an embodiment. As shown in FIG. 1, the method for manufacturing a laminate according to the embodiment includes a step S1 of preparing a laminate precursor, and a step S2 of irradiating the laminate precursor with energy rays. By performing step S2 after step S1, a laminate as a final product can be manufactured.

<Step of preparing laminate precursor>
The step S1 of preparing a laminate precursor can be performed, for example, by preparing a laminate precursor 10 shown in a schematic cross-sectional view of FIG. 2. The step of preparing the laminate precursor 10 includes, for example, the step of preparing the base material 11, the step of forming the base ink layer 12 on the base material 11, and the step of forming the ink layer 13 containing inorganic flakes on the base ink layer 12. and a step of forming the heat generating layer 14 on the inorganic flake-containing ink layer 13. The laminate precursor 10 prepared in this manner includes a heat generating layer 14 located opposite to the inorganic flake-containing ink layer 13 and on the opposite side of the base material 11 of the inorganic flake-containing ink layer 13.

(Process of preparing base material)
The step of preparing the base material 11 can be performed, for example, by preparing a plastic film that can support at least the ink layer 13 containing inorganic flakes. The plastic film constituting the base material 11 may be transparent. When the base material 11 is transparent, the total light transmittance of the base material 11 is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The total light transmittance can be measured, for example, according to JIS K 7105 (Plastic optical property testing method).

The plastic film constituting the base material 11 may be, for example, a polyester resin (polyethylene terephthalate, polyethylene naphthalate, polylactic acid, PETG (polyethylene terephthalate) in which part or all of ethylene glycol, which is the glycol component of polyethylene terephthalate, is replaced with cyclohexanedimethanol or neopentyl). polyester resins substituted with glycol, etc.), polystyrene resins (polystyrene, styrene-butadiene copolymers, etc.), polyolefin resins (polyethylene, polypropylene, cyclic polyolefin resins, etc.), polyvinyl chloride resins, A plastic film containing a polyamide resin, an aramid resin, a polyimide resin, a polyphenylene sulfide resin, an acrylic resin, or the like can be prepared. The plastic film constituting the base material 11 may contain one type of these resins, or may contain two or more types of these resins.

As the plastic film constituting the base material 11, for example, a heat-shrinkable plastic film (shrink film) or a non-heat-shrinkable plastic film can be prepared. Among them, a heat-shrinkable plastic film is preferably prepared. It is preferable. In this case, by heating the laminate manufactured by the laminate manufacturing method of the embodiment and shrinking the base material 11, a gap between the irradiated part and the non-irradiated part of the energy ray, which will be described later, in the laminate is made. There is a tendency that the expressivity of variable printing can be improved by increasing the contrast of diffused reflection. The heat shrinkage rate of the heat-shrinkable plastic film in the main shrinkage direction can be, for example, 40% or more and 95% or less when the heat-shrinkable plastic film is immersed in 90°C hot water for 10 seconds. , preferably 50% or more and 90% or less.

The plastic film prepared as the base material 11 may be a single-layer plastic film consisting of one layer, or may be a multi-layer plastic film consisting of two or more layers. Further, the thickness of the plastic film prepared as the base material 11 can be, for example, 5 μm or more and 100 μm or less.

(Process of forming a base ink layer on the base material)
The step of forming the base ink layer 12 on the base material 11 includes, for example, applying an ink for forming the base ink layer 12 (hereinafter referred to as "base ink"), which is a precursor of the base ink layer 12, on the base material 11. This can be done by printing and then drying. As the base ink, for example, an oil-based ink containing an organic solvent and a resin, or an aqueous ink containing an aqueous solvent and a resin (if the resin is dissolved in the aqueous solvent, or if the resin is not dissolved in the aqueous solvent) (including any case (emulsion)) can be used. The base ink can be printed by, for example, flexo printing, gravure printing, screen printing, inkjet printing, liquid toner printing, or the like. Drying of the base ink can be performed, for example, by volatilizing at least a portion of the solvent of the base ink. The thickness of the base ink layer 12 can be, for example, approximately 0.1 μm or more and 10 μm or less.

Examples of resins contained in the base ink include acrylic resins, urethane resins, polyester resins, polyamide resins, cellulose resins, vinyl chloride resins, vinyl acetate resins, and polyolefin resins (for example, polyethylene resins). , or polybutadiene-based resin, etc.), isocyanate-based resin, rosin resin, polyvinyl alcohol-based resin (PVA-based resin), or imine-based resin, which can be softened by increasing the temperature by irradiation with energy rays, which will be described later. Resin can be used. As the resin contained in the base ink, for example, one having a softening temperature lower than that of the resin constituting the inorganic flake-containing ink layer 13 may be used.

As the resin contained in the base ink, it is preferable to use a thermoplastic resin. In this case, the direction of the inorganic flakes in the inorganic flake-containing ink layer 13 tends to be easily changed by irradiation with energy rays, as will be described later. As the thermoplastic resin contained in the base ink, for example, acrylic resin, urethane resin, cellulose resin, etc. can be used. As the base ink, from the viewpoint of ensuring visibility of the inorganic flake-containing ink layer 13 from the base material 11 side, for example, a colorless and transparent ink or a colored and transparent ink can be used.

(Step of forming an ink layer containing inorganic flakes on the base ink layer)
In the step of forming the ink layer 13 containing inorganic flakes on the base ink layer 12, for example, an ink for forming the ink layer 13 containing inorganic flakes (hereinafter referred to as This can be done by printing and then drying an ink containing inorganic flakes. As the inorganic flake-containing ink, for example, an ink containing inorganic flakes, a solvent such as an organic solvent or an aqueous solvent, and a resin can be used. Printing with the ink containing inorganic flakes can be performed by, for example, flexographic printing, gravure printing, screen printing, inkjet printing, liquid toner printing, or the like. The ink containing inorganic flakes can be dried by, for example, volatilizing at least a portion of the solvent in the ink containing inorganic flakes. The inorganic flake-containing ink layer 13 may be a layer that has a sense of brightness due to the inorganic flakes, for example. Further, the inorganic flake-containing ink layer 13 may be, for example, a layer having concealing properties (the property that the back side is difficult to see through). The inorganic flake-containing ink layer 13 can be a layer that exhibits a metallic appearance such as silver and has a concealing property, for example, when aluminum flakes, which will be described later, are used as the inorganic flakes.

As the inorganic flakes contained in the inorganic flake-containing ink layer 13, for example, aluminum flakes, brass flakes, metal flakes other than aluminum flakes, mica flakes, or other metal oxide flakes can be used. When using aluminum flakes as the inorganic flakes, it is preferable to use aluminum flakes produced by a normal ball mill method or aluminum flakes produced by a vapor deposition method. These inorganic flakes may be used alone as inorganic flakes included in the ink layer 13 containing inorganic flakes, or two or more types may be used in combination.

The shape of the inorganic flakes may be flat, for example. Ratio of the thickness of the inorganic flake (the maximum thickness of the inorganic flake) to the length in the longitudinal direction of the flat surface of the inorganic flake (the longest length of the surface of the inorganic flake) The aspect ratio ((thickness of inorganic flakes)/(length in the longitudinal direction of the surface of inorganic flakes)) can be, for example, 1/5 or more and 1/1000 or less, preferably 1/10 or more. It can be reduced to 1/100 or less. For example, the flat inorganic flakes may have a smooth surface. When the flat inorganic flakes have smooth surfaces, for example, the smooth surfaces of the inorganic flakes can be arranged so as to face substantially the same direction.

Examples of resins contained in the ink containing inorganic flakes include acrylic resins, urethane resins, polyester resins, polyamide resins, cellulose resins, vinyl chloride resins, vinyl acetate resins, and polyolefin resins (for example, polyethylene (or polybutadiene-based resin, etc.), isocyanate-based resin, rosin resin, polyvinyl alcohol-based resin (PVA-based resin), or imine-based resin. These resins may be used alone as resins contained in the inorganic flake-containing ink, or two or more types may be used in combination. From the viewpoint of more easily changing the direction of the inorganic flakes at a location irradiated with energy rays, which will be described later, it is preferable to use a thermoplastic resin as the resin contained in the ink containing inorganic flakes.

(Step of forming a heat generating layer on an ink layer containing inorganic flakes)
The step of forming the heat generating layer 14 on the inorganic flake-containing ink layer 13 includes, for example, applying an ink for forming the heat generating layer 14 (hereinafter referred to as "heat generating ink"), which is a precursor of the heat generating layer 14, on the inorganic flake containing ink layer 13. This can be done by printing and then drying. As the exothermic ink, an ink containing an absorbent capable of absorbing energy rays, a solvent such as an organic solvent or an aqueous solvent, and a resin, which will be described later, can be used. Printing with heat-generating ink can be performed, for example, by flexographic printing, gravure printing, screen printing, inkjet printing, liquid toner printing, or the like. The exothermic ink can be dried, for example, by volatilizing at least a portion of the solvent in the exothermic ink.

As the absorbent contained in the heat-generating ink, for example, an ultraviolet absorber, an infrared absorber, a near-infrared absorber, carbon black, or the like can be used. As the resin contained in the exothermic ink, for example, the same binder resin as the binder resin contained in the inorganic flake-containing ink can be used.

<Step of irradiating the laminate precursor with energy rays>
The step S2 of irradiating the laminate precursor 10 with the energy rays 15 may be performed, for example, by irradiating the heat generating layer 14 of the laminate precursor 10 with the energy rays 15, as shown in the schematic cross-sectional view of FIG. I can do it. Although FIG. 3 shows an example in which the energy rays 15 are irradiated from the base material 11 side, the energy rays 15 may be irradiated from the heat generating layer 14 side. However, it is preferable to irradiate the energy rays 15 from the base material 11 side.

Examples of energy rays 15 include laser light, microwaves (light with a wavelength of 1 mm or more and 1 m or less), ultraviolet rays (light with a wavelength of 10 nm or more and 400 nm or less), visible light (light with a wavelength of 400 nm or more and 700 nm or less), or infrared rays (light with a wavelength of 800 nm or more). or more and less than 1000 nm), etc. can be irradiated. Among these, it is preferable to irradiate the energy beam 15 with a laser beam. Examples of laser light include ultraviolet laser light (wavelength: 10 nm or more and 400 nm or less), YAG laser light (wavelength: 1.064 μm), fiber laser light (wavelength: 1030 nm or more and 1070 nm or less), or infrared laser light (wavelength: 780 nm or more and 16 μm or less). etc. can be irradiated.

In the step of irradiating the laminate precursor 10 with energy rays 15, the absorbent in the heat generating layer 14 of the laminate precursor 10 absorbs the energy rays 15 and generates heat, heating the heat generating layer 14. Heat is transferred to the inorganic flake-containing ink layer 13 and the base ink layer 12. The heat transferred to the base ink layer 12 softens and deforms the base ink layer 12, causing unevenness to occur at the interface between the base ink layer 12 and the ink layer containing inorganic flakes 13, and causing unevenness on the surface of the base ink layer 12. The orientation of the inorganic flakes in the inorganic flake-containing ink layer 13 on the uneven surface changes. Thereafter, the base ink layer 12 and the inorganic flake-containing ink layer 13 are cooled while the orientation of the inorganic flakes in the inorganic flake-containing ink layer 13 is changed, thereby producing a laminate 20 as a final product.

When the entire laminate precursor 10 is irradiated with the energy rays 15, the area irradiated with the energy rays 15 after irradiation with the energy rays 15 of the final product laminate 20 is different from before the irradiation with the energy rays 15. The orientation of the inorganic flakes in the ink layer 13 containing inorganic flakes changes. Furthermore, when the laminate precursor 10 is partially irradiated with the energy rays 15, the orientation of the inorganic flakes in the inorganic flake-containing ink layer 13 at the non-irradiated portions of the laminate 20, which is the final product, is determined by the energy. Although there is no change from before irradiation with the energy ray 15, only the orientation of the inorganic flakes in the inorganic flake-containing ink layer 13 at the irradiation location with the energy ray 15 has changed. Therefore, in both cases where the entire laminate precursor 10 is irradiated with the energy rays 15 and when a part of the laminate precursor 10 is irradiated with the energy rays 15, the laminate 20 that is the final product is When visually recognized from the material 11 side, it is possible to express the laminate 20 as the final product by causing diffuse reflection at the irradiation location of the energy rays 15. Improved variable printing is possible. For example, when a part of the laminate precursor 10 is irradiated with the energy rays 15, two areas can be formed with different brightness depending on the area irradiated with the energy rays 15 and the area not irradiated with the energy rays 15.

FIG. 4 shows a schematic plan view of the laminate 20 manufactured by the laminate manufacturing method of the embodiment, as viewed from the base material 11 side. FIG. 5 shows a schematic plan view when the base material 11 of the laminate 20 shown in FIG. 4 is viewed from the base material 11 side after the base material 11 is heat-shrinked. As is clear from the comparison between FIG. 4 and FIG. 5, the design of the inorganic flake-containing ink layer 13 can be displayed more clearly by further performing the step of heat shrinking the base material 11 of the laminate 20. , it becomes possible to further improve the decorative properties of the final product, the laminate 20. The heat shrinkage rate of the base material 11 of the laminate 20 in the main shrinkage direction in the step of heat shrinking the base material 11 of the laminate 20 can be, for example, 5% or more.

In addition, in the above, as shown in FIG. 3, for example, a laminate in which a base material 11, a base ink layer 12, an ink layer containing inorganic flakes 13, and a heat generating layer 14 are laminated in this order from the bottom to the top. Although the case where the body precursor 10 is irradiated with energy rays has been described, for example, as shown in the schematic cross-sectional view of FIG. The laminate precursor 10 formed by laminating the containing ink layers 13 in this order may be irradiated with energy rays. Further, in the laminate precursor 10 illustrated in FIGS. 3 and 6, for example, at least one layer selected from the group consisting of the base ink layer 12, the inorganic flake-containing ink layer 13, and the heat generating layer 14 is formed on the base material 11. It may be provided in a portion.

The laminate 20, which is the final product, can be used as a label such as a shrink label, a wrap label, a heat-sensitive label, a tack label, or an in-mold label, or a film package such as an overwrap package or a pouch package. However, it is preferable to use it as a shrink label or an overlapping shrink package that can be used after being heat-shrinked. In this case, the step of heat-shrinking the shrink label or overlapping shrink packaging and attaching it to the article to be attached may be the step of heat-shrinking the base material 11 described above. In this case, an article to which the laminate 20, which is a final product, is attached can be obtained. In addition, when using the laminate 20 as a final product as a shrink label, there are a step of preparing the laminate precursor 10, a step of making the laminate precursor 10 into a cylindrical shape, and a step of forming the cylindrical laminate precursor 10. A method for manufacturing an article to which a laminate 20 is attached includes, in this order, a step of manufacturing a laminate 20 by irradiating the laminate 20 with energy rays 15, and a step of attaching the laminate 20 to an article by heat-shrinking the laminate 20. It is preferable.

Although the embodiments have been described as above, it is planned from the beginning to combine the configurations of the above-mentioned embodiments as appropriate.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

Reference Signs List 10 laminate precursor, 11 base material, 12 base ink layer, 13 ink layer containing inorganic flakes, 14 heat generating layer, 20 laminate.

Claims (5)

preparing a laminate precursor comprising a base material and an ink layer containing inorganic flakes on the base material;
irradiating the laminate precursor with energy rays,
The inorganic flake-containing ink layer contains inorganic flakes,
In the step of irradiating the energy rays, the direction of the inorganic flakes at the location irradiated with the energy rays changes. The method for manufacturing a laminate according to claim 1, wherein the laminate precursor further includes a heat generating layer facing the ink layer containing inorganic flakes. The base material is a heat-shrinkable plastic film,
The method for manufacturing a laminate according to claim 1 or 2, further comprising the step of shrinking the base material after the step of irradiating the energy ray. The method for manufacturing a laminate according to any one of claims 1 to 3, wherein the laminate precursor further includes a base ink layer between the base material and the inorganic flake-containing ink layer. The method for manufacturing a laminate according to claim 4, wherein the base ink layer contains a thermoplastic resin.

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