Labeled container and method for manufacturing same

Abstract

According to the present invention, the possibility of burrs occurring at the edge of an opening is reduced, or the size of burrs is reduced.　In a labeled container (10), a label (3) includes a base material that is heat-shrinkable in at least a lateral direction and that contains a polyester resin recycled from PET products, and has an opening portion (32) formed by cutting a part of the label by irradiating the label with laser light.

Description

Labeled Container and Method for Manufacturing the Same

[0001] The present disclosure relates to a labeled container including a container and a label attached to the container, and a method for manufacturing the same.

[0002] In a labeled container including a container and a label attached to the container, a labeled container in which a part of the label is cut is known. For example, a labeled container having an opening formed by cutting a part of the label located at the handle portion is known.

[0003] In manufacturing such a labeled container, a technique for cutting a part of the label attached to the container with laser light is disclosed in Patent Document 1. Usually, with laser light whose output is adjusted according to the thickness of the label, a part of the removal target area is cut so as to be connected to the label body, and then, by tearing off the removal target area, a labeled container with an opening in a part of the label is manufactured.

[0004] Japanese Patent Translation of PCT International Publication No. 2017-536300

[0005] However, when the removal target area is torn off, burrs occur at the torn portion, that is, the edge of the opening.

[0006] One aspect of the present disclosure aims to realize a labeled container capable of reducing the possibility of burrs occurring or making the burrs smaller.

[0007] A labeled container according to one aspect of the present disclosure is a labeled container including a container and a label attached to the container in a heat-shrunk state, wherein the circumferential direction of the container is the lateral direction of the label, the direction perpendicular to the lateral direction is the longitudinal direction of the label, the label has heat shrinkability at least in the lateral direction, and includes a base material containing a polyester resin recycled from a PET (polyethylene terephthalate) product, and the label has an opening formed by cutting a part of the label by irradiating the label with laser light.

[0008] A method for manufacturing a labeled container according to one aspect of the present disclosure is a method for manufacturing a labeled container comprising a container and a label to be attached to the container, wherein, with the label attached to the container, the circumferential direction of the container is defined as the transverse direction of the label, the direction perpendicular to the transverse direction is defined as the vertical direction of the label, the label comprises a base material having heat shrinkability in at least the transverse direction and containing a polyester resin recycled from PET (polyethylene terephthalate) products, and includes an attachment step of attaching the label to the container by heat shrinking the label; an irradiation step of irradiating the edge of the area of ​​the label to be removed with laser light while the label is attached to the container; and a cutting step of forming an opening by cutting a part of the edge that was not cut by the irradiation of the laser light.

[0009] According to one aspect of this disclosure, the possibility of burrs forming on the edges of the opening can be reduced, or the size of the burrs can be reduced.

[0010] This is a front view showing an example of the appearance of a labeled container. This is a front view showing an example of a container. This is a side view showing an example of a container. This is a diagram showing an example of a label formed in a cylindrical shape. This is a diagram showing an example of the results of differential scanning calorimetry on a substrate. This is a diagram showing an example of the results of differential scanning calorimetry on a substrate. This is a diagram showing a cylindrical label attached to a container. This is a diagram showing a cylindrical label attached to a container. This is a table showing an example of the results of the ratio of the longitudinal tear strength to the transverse tear strength and the state of the removal area for the thickness of the label and the recycled material content. This is a diagram showing an example of the state of the removal area in a label attached to a container in a heat-shrunk state. This is a diagram showing an example of the cross-section of the first edge and the second edge.

[0011] The present disclosure will be described in detail below with reference to the drawings. In this specification, the "front" of a labeled container and the "front" of a container refer to the side that is visible when the container is standing upright on a horizontal plane and viewed from any one direction perpendicular to the axial direction of the container, and the "back" of a labeled container and the "back" of a container refer to the opposite side. It should also be noted that the dimensions, scale, and shape of the parts and components shown in each figure may differ from those of the actual parts.

[0012] [Technical Concept of Labeled Containers in This Disclosure] The technical scope of this disclosure includes both a configuration in which laser light is irradiated in an endless manner and a configuration in which the start and end positions of the laser light irradiation are offset, rather than being endless. First, as one embodiment of this disclosure, an embodiment based on the premise of irradiating laser light in an endless manner will be described.

[0013] Figure 1 is a front view showing an example of the appearance of a labeled container 10. As shown in Figure 1, in the labeled container 10, the label 3 has an opening 32. When forming the opening 32, one possible method is to irradiate the label 3 with laser light in an endless manner, such that the start and end positions of the laser light irradiation are offset, and then tear off the area where the start and end positions are offset. However, in this case, burrs are likely to form at that location, or tears (break lines) are likely to form from that location. Therefore, in this embodiment, laser light is irradiated in an endless manner to form the opening 32. Endless means that the trajectory of the laser light, starting from the irradiation start point, returns to the irradiation start point again.

[0014] In this case, if the label 3 is cut along the entire trajectory of the endlessly irradiated laser beam, a portion of the label 3 (the area to be removed) will fall onto the manufacturing line. Therefore, when irradiating with an endless laser beam, it is required to cut the label 3 in a way that prevents the area to be removed from falling onto the line.

[0015] After diligent research, the inventors have discovered that if a label containing polyester resin recycled from PET (polyethylene terephthalate) products is used as label 3, even if the label 3 is continuously irradiated with laser light, a portion of the trajectory will not be cut. In other words, the inventors have found that by using a label containing polyester resin recycled from PET products as label 3, even if the label 3 is continuously irradiated with laser light, the possibility of the area to be removed falling onto the manufacturing line can be reduced. As a result, the possibility of burr formation can be reduced. In the following description, "polyester resin recycled from PET products" will be referred to as "recycled material".

[0016] [Labeled Container] As shown in Figure 1, the labeled container 10 comprises a container 1 and a label 3 attached to the container 1 in a heat-shrunk state. In the labeled container 10, the label 3 is attached to the outer surface of the main body 11 of the container 1 in a heat-shrunk state along the circumferential direction. In this embodiment, when the label 3 is attached to the labeled container 10, the circumferential direction of the container 1 is described as the horizontal direction of the label 3, and the direction perpendicular to the horizontal direction is described as the vertical direction. That is, the vertical direction (up and down direction) is the axial direction of the container 1 (the direction in which the perpendicular line of the bottom surface of the container 1 extends), and coincides with the direction in which the label 3 is placed over the container 1.

[0017] <Container> Figure 2 is a front view showing an example of container 1. Figure 3 is a side view showing an example of container 1. As shown in Figures 2 and 3, container 1 has a main body portion 11 having a storage space for storing contents, a spout 12 formed at the end of the main body portion 11, and a lid portion 13 that is detachably attached to the main body portion 11 and closes the spout 12. The main body portion 11 also has a bottom portion 14 on the opposite side of the spout 12 to allow container 1 to stand on its own.

[0018] The material of container 1 is not particularly limited and includes synthetic resin, glass, ceramics, metal, paper, etc. The shape of container 1 is also not particularly limited and may be approximately cylindrical, approximately elliptical, approximately polygonal, approximately conical, approximately frustum, approximately gourd-shaped, approximately daruma-shaped, or a three-dimensional shape that combines these shapes.

[0019] Furthermore, the main body portion 11 has a recessed portion 2 that is recessed toward the storage space. The recessed portion 2 has a peripheral edge portion 2a and a peripheral surface portion 2b which is the outer surface of the main body portion 11 that is recessed toward the storage space (the portion that does not come into contact with the heat-shrinkable label 3).

[0020] In this embodiment, the recessed portion 2 is formed so that the side of the main body portion 11 functions as a handle portion 15. In this embodiment, the recessed portion 2 is provided in communication with the front and back sides of the container 1, and the circumferential portion 2b defines the hole portion 16. This allows the consumer to insert their fingertips into the hole portion 16 and grasp the handle portion 15 by wrapping their fingers around it. The shape, position, and number of recessed portions 2 can be arbitrarily determined according to the intended use of the container 1.

[0021] The contents to be filled into container 1 are not particularly limited and include beverages, seasonings, sanitary products, pharmaceuticals, cosmetics, etc. Furthermore, the contents are not particularly limited in their properties as long as they can be removed from the storage space, and may be liquid (including liquids with a certain degree of viscosity), granular, or powder.

[0022] <Label> Figure 4 shows an example of a label 3 formed in a cylindrical shape. As shown in Figure 4, the label 3 has a base material 31. The base material 31 is mainly composed of a heat-shrinkable polyester film containing recycled material, which has heat shrinkability at least in the transverse direction.

[0023] A heat-shrinkable polyester film is a flexible film that shrinks in the direction of heat shrinkage when heated to its heat shrinkage temperature. Examples of heat shrinkage temperatures include 60°C to 120°C. The thickness of the heat-shrinkable polyester film is not particularly limited, but for example, it can be 12 m to 100 μm, or more specifically, 12 μm to 80 μm.

[0024] Furthermore, the base material 31 may be a heat-shrinkable polyester film provided with a design printing layer, a base printing layer, a protective layer, a slip layer, a matte layer, and the like. In this case, the thickness of the base material 31 is, for example, 15 μm to 120 μm, and moreover, approximately 20 μm to 90 μm.

[0025] The base material 31 may contain amorphous components (amorphous glycol components and amorphous acid components). The sum of the proportion of amorphous glycol components in 100 mol% of total glycol components and the proportion of amorphous acid components in 100 mol% of total acid components may be 10 mol% or more and 40 mol% or less.

[0026] Examples of monomers for amorphous acid components (dicarboxylic acid components) include isophthalic acid, 1,4-cyclohexanedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. Examples of monomers for amorphous glycol components (diol components) include neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-isopropyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, and hexanediol.

[0027] Various additives may be added to the base material 31 as needed. The additives are not particularly limited and may be known additives such as waxes, antioxidants, antistatic agents, nucleating agents, viscosity reducers, heat stabilizers, coloring pigments, color inhibitors, ultraviolet absorbers, and antiblocking agents.

[0028] (Recycled Material) The recycled material used as a polyester raw material for the base material 31 contains ethylene terephthalate units in an amount of 90 mol% or more of the total ester units in a 100 mol% ratio. Preferably, it is 95 mol% or more, and most preferably 100 mol%. The ethylene terephthalate units contain ethylene glycol and terephthalic acid as the main constituent components. By using ethylene terephthalate, excellent heat resistance and transparency can be obtained as a heat-shrinkable polyester film.

[0029] The base material 31 contains 1% by weight or more and 100% by weight or less of recycled material. The higher the recycled material content, the better, with 100% by weight being the most preferred form. The lower limit of the recycled material content is preferably 3% by weight, preferably 5% by weight, and more preferably 25% by weight.

[0030] Recycled materials are materials made from recycled PET products. It should be noted that the polyester used in PET products (e.g., PET bottles) undergoes crystallinity control to improve the product's appearance, and as a result, polyester containing 10 mol% or less of isophthalic acid as an acid component may be used.

[0031] The recycled material may contain amorphous components (amorphous glycol components and amorphous acid components). The sum of the proportion of amorphous glycol components in 100 mol% of total glycol components and the proportion of amorphous acid components in 100 mol% of total acid components may be 0 mol% or more and 5 mol% or less. The lower the content of amorphous components, the better, and most preferably it is 0 mol%. The recycled material may be, for example, A-PET (amorphous polyethylene terephthalate). From the viewpoint of reducing environmental impact, the recycled material is preferably a resin made from recycled PET bottles. Examples of monomers for amorphous components and monomers for amorphous glycol components are the same monomers as described above.

[0032] Furthermore, various additives may be added to the recycled material as needed. The additives are not particularly limited and may be known additives such as waxes, antioxidants, antistatic agents, nucleating agents, viscosity reducers, heat stabilizers, coloring pigments, color inhibitors, and ultraviolet absorbers.

[0033] The intrinsic viscosity of the recycled material may be in the range of 0.50 dl / g or more and 0.80 dl / g or less. If the intrinsic viscosity is lower than 0.50, the effect of improving tear resistance decreases, while if it is higher than 0.80 dl / g, the increase in filtration pressure becomes large, making high-precision filtration difficult. The above intrinsic viscosity is more preferably 0.52 dl / g or more and 0.78 dl / g or less, even more preferably 0.52 dl / g or more and 0.75 dl / g or less, and particularly preferably 0.52 dl / g or more and 0.73 dl / g or less.

[0034] The recycled material used for the base material 31 is produced, for example, as follows: After washing away foreign matter such as remaining beverage from a PET beverage bottle, which is an example of a PET product, the flakes obtained by crushing are melted in an extruder. Then, by sequentially changing the filter to one with a finer mesh size and filtering out fine foreign matter several times, the recycled material used for the base material 31 is produced.

[0035] Furthermore, heat-shrinkable polyester films can be manufactured by known methods. For example, a heat-shrinkable polyester film can be manufactured by preheating an unstretched film obtained by melt-extruding recycled material using an extruder, and then laterally stretching the preheated unstretched film. The temperature during preheating and the temperature during later stretching may be different from or the same as each other. Alternatively, the preheated unstretched film may be laterally stretched and then further stretched. The temperatures during these later stretching processes may also be different from or the same as each other.

[0036] Furthermore, the heat-shrinkable polyester film may be a heat-shrinkable synthetic resin film, a heat-shrinkable nonwoven fabric, or a heat-shrinkable foamed resin film (for example, a milky white film with cavities within the film, which may also contain a white pigment), as well as laminated films of these. The laminated film may be a laminate of a non-heat-shrinkable layer and a heat-shrinkable layer, provided that the laminate as a whole is heat-shrinkable, but it is preferable that all layers are heat-shrinkable.

[0037] A synthetic resin film or a synthetic resin laminated film may be used as the heat-shrinkable polyester film. Furthermore, the heat-shrinkable polyester film may have a gas and / or light barrier layer, such as a metal vapor-deposited layer, laminated to it as needed.

[0038] The synthetic resin film or synthetic resin laminate film may contain recycled materials and may also contain other materials as exemplified below. These materials include olefin resins such as polyethylene, polypropylene, and cyclic olefins; polystyrene resins such as polystyrene and styrene-butadiene copolymers; polyamide resins; and thermoplastic resins such as vinyl chloride resins, one or more of which are selected. These resins may be made from recycled labels attached to PET bottles, etc. From the viewpoint of being easily cut by laser light, polystyrene resins may be selected in addition to recycled materials.

[0039] The multilayer structure of a laminated film is represented by an outer layer / intermediate layer / inner layer, and examples include an outer layer / one intermediate layer / inner layer, or an outer layer / first intermediate layer / second intermediate layer / third intermediate layer / inner layer. It is sufficient that recycled material is contained in at least one of these layers. When the laminated film contains recycled material and polystyrene resin, these layers may be layers whose main component is either recycled material, polystyrene resin, or a mixed resin of recycled material and polystyrene resin.

[0040] (Heat Shrinkage Rate) The heat shrinkage rate in the transverse direction of a heat-shrinkable polyester film is not particularly limited, but from the viewpoint of label suitability, it is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. A higher heat shrinkage rate in the transverse direction is preferable, but there is a limit to this, so theoretically the heat shrinkage rate in the transverse direction is less than 100%, but it is usually 90% or less, and preferably 85% or less.

[0041] Furthermore, the thermal shrinkage rate in the longitudinal direction of heat-shrinkable polyester film is between 0% and less than 7% from the viewpoint of label suitability. The higher the thermal shrinkage rate of heat-shrinkable polyester film, the easier it is to cut with laser light. However, if the thermal shrinkage rate in the longitudinal direction is high, it is prone to tearing in the longitudinal direction. The thermal shrinkage rate in the longitudinal direction is set taking this point into consideration.

[0042] Furthermore, because the thermal shrinkage rate in the vertical direction is at least 0% and less than 7%, the edges 33 of the opening 32 do not shrink excessively after being irradiated with laser light. As a result, the opening 32 can be formed as designed (i.e., with high precision). Also, because the edges 33 of the opening 32 do not shrink excessively, unnecessary irregularities are less likely to occur on the label 3, and as a result, a label 3 with a pleasant feel can be provided.

[0043] Incidentally, the above heat shrinkage rate is the ratio of the length of the film before heating (original length) to the length of the film after immersion in warm water at 100°C for 10 seconds (length after immersion), and is obtained by substituting into the following formula: Heat shrinkage rate (%) = [{(original length in the horizontal or vertical direction) - (length after immersion in the horizontal or vertical direction)} / (original length in the horizontal or vertical direction)] × 100.

[0044] (Inspection method for the presence or absence of recycled material) Figures 5 and 6 are diagrams showing an example of the results of differential scanning calorimetry (DSC: Differential Scanning Calorimetry) for a base material. Figure 5 shows the DSC results for a base material that does not contain recycled material, and Figure 6 shows the DSC results for a base material that contains recycled material. Reference numeral 101 in Figure 6 shows the DSC results for a base material containing 5% by weight of recycled material, and reference numeral 102 shows the DSC results for a base material containing 25% by weight of recycled material. In the graphs of Figures 5 and 6, the vertical axis indicates heat flow [unit: mW], and the horizontal axis indicates temperature [unit: °C]. For the DSC measurement, "DSC6200" manufactured by Seiko Instruments Inc. was used, and the measurement was carried out under the condition of increasing the temperature from 30°C to 300°C at a rate of 10°C / min.

[0045] As shown in Figure ⑥, in the base material containing recycled material, it can be seen that a specific endothermic peak (the part indicated by the triangular mark in the figure) appears in the range of 200°C or higher and 250°C or lower (the shaded part). Also, it can be seen that the higher the addition ratio of the recycled material, the more prominent the endothermic peak. On the other hand, as shown in Figure ⑤, in the base material that does not contain recycled material, it can be seen that no specific endothermic peak appears in the range of 200°C or higher and 250°C or lower. The above endothermic peak is considered to be derived from the melting of the crystals contained in the recycled material. Thus, by performing DSC on the base material, it is possible to inspect whether the base material contains recycled material.

[0046] (Configuration of the Label When Attached to the Labeled Container) As shown in FIG. 1, in the state where the label 3 is attached to the labeled container 10, the label 3 has an opening 32 formed by cutting a part of the label 3 by irradiating the label 3 with laser light so that the laser light draws an endless locus Z (see FIG. 8). Further, the label 3 has an edge 33 of the base material 31 that defines the opening 32 (that is, the edge 33 of the opening 32).

[0047] As described above, the container 1 has a recess 2 having a hole 16 in order to make a part of the container 1 function as a handle part 15. Therefore, in the present embodiment, the opening 32 is formed at a position corresponding to the recess 2 in the plane of the label 3 so that the opening 32 communicates with the recess 2. In the example of FIG. 1, the opening 32 is formed along the peripheral edge 2a of the recess 2 in the label 3. The shape of the opening 32 is not particularly limited and may be a substantially elliptical shape, a substantially circular shape, a substantially rectangular shape, or a shape in which these shapes are combined.

[0048] Further, as shown in FIG. 11, the thickness T1 of the first edge 33a of the opening 32 appearing in the first cross-section when the label 3 is cut along the vertical direction is thinner than the thickness T2 of the second edge 33b of the opening 32 appearing in the second cross-section when the label 3 is cut along the horizontal direction. That is, the thickness T1 of the first edge 33a of the base material 31 that defines the opening 32 appearing in the first cross-section is thinner than the thickness T2 of the second edge 33b of the base material 31 that defines the opening 32 appearing in the second cross-section. The first cross-section refers to the Y - Y cross-section at the reference numeral 201 in FIG. 10, and the second cross-section refers to the X - X cross-section at the reference numeral 201 in FIG. 10.

[0049] FIG. 11 is a diagram showing an example of the cross-sections of the first edge 33a and the second edge 33b. The reference numeral 301 in FIG. 11 indicates the second cross-section, and the reference numeral 302 indicates the first cross-section. In the reference numeral 302 in FIG. 11, the portion surrounded by the dotted line shows the cross-section of the base material 31 after cutting a part of the edge 35a of the removal target region 35 that was not cut by the laser light.

[0050] [Method for Manufacturing Labeled Containers] Next, an example of a method for manufacturing labeled containers 10 will be described. Figure 7 shows a state in which a cylindrical label 3 is attached to the container 1. Figure 8 shows a state in which the cylindrical label 3 is attached to the container 1.

[0051] The label 3 before heat shrinking may be made by cutting a flat film that constitutes the label 3 to the appropriate length according to the circumference of the container 1 to which it will be attached. As shown in Figure 4, in the label 3 after cutting, the base material 31 has a first end 31a and a second end 31b that extend in the longitudinal direction. As shown in Figure 4, the label 3 is formed into a cylindrical shape by rolling the base material 31 into a cylindrical shape and overlapping and bonding the first end 31a of the base material 31 to the second end 31b to form a seal portion 31c. The seal portion 31c extends in a strip shape in the longitudinal direction of the label 3. The method of bonding the first end 31a and the second end 31b is not particularly limited and can include solvent welding, adhesive bonding, ultrasonic welding, etc.

[0052] (Attachment Process) As shown in Figure 7, the cylindrical label 3 is placed over the outside of the attachment area of ​​the container 1 (applied as an outer covering). The attachment area is most of the main body 11, including the recessed portion 2. At the time the label 3 is placed over the container 1, it is not attached to the container 1. With the label 3 attached to the container 1, the label 3 is heated and heat-shrinked, thereby attaching the label 3 to the container 1 as shown in Figure 8. By making the circumference of the label 3 larger than the maximum circumference of the attachment area of ​​the container 1, it can be easily attached.

[0053] The heating temperature for label 3 is not particularly limited, and may be, for example, 60°C to 120°C, preferably 80°C to 110°C, based on the outer surface of label 3. Furthermore, heating of label 3 may be carried out using, for example, steam, hot air, or irradiation with active energy rays such as radiation, ultraviolet rays, or infrared rays.

[0054] Label 3 adheres closely to almost the entire outer surface of the main body 11, including the handle portion 15, except for the surface of the recessed portion 2 (circumferential portion 2b (see Figure 3)). That is, the portion of label 3 corresponding to the recessed portion 2 (the area surrounded by the laser beam trajectory Z, which is the removal target area 35 to be removed from the labeled container 10) is separated from the circumferential portion 2b. Furthermore, the removal target area 35 has not shrunk to its shrinkage limit. The shrinkage limit refers to the state at which label 3 does not shrink any further when heated to a predetermined temperature. For example, in the case of label 3 with a lateral thermal shrinkage rate of 40% at 100°C, the shrinkage limit can be said to be the state of label 3 that has shrunk by 40% when heated at 100°C.

[0055] (Irradiation Process) Next, with the label 3 attached to the container 1, laser light is irradiated onto the edge 35a (outer edge of the area to be removed 35) of the area to be removed 35 so as to trace an endless trajectory Z on the label 3. As shown in Figure 8, in this embodiment, the laser light is irradiated along the peripheral edge 2a of the recessed portion 2. In this embodiment, the endless trajectory Z is located slightly outside the peripheral edge 2a. The position of the endless trajectory Z is not limited to this, and may coincide with the peripheral edge 2a, or may be slightly inside the peripheral edge 2a. Furthermore, the position of the endless trajectory Z can be appropriately set according to the size and shape of the opening 32 formed in the label 3.

[0056] By irradiating the area 35 to be removed with laser light along an endless trajectory Z, a portion of the edge 35a of the area 35 to be removed is not cut, while the remaining portion is cut by the laser light. As shown in Figure 8, in this embodiment, portions P1 and P2 are not cut by the laser light irradiation. In this embodiment, portion P1 is included in the upper region of the area 35 to be removed, and portion P2 is included in the lower region of the area 35 to be removed. Therefore, at the time when the laser light irradiation is completed, the area 35 to be removed is connected to the rest of the label 3, and the opening 32 has not been formed.

[0057] The type of laser is not particularly limited as long as it can cut label 3, and examples include carbon dioxide lasers, YAG lasers, and YVO4 lasers. The wavelength of the laser light may be, for example, 10 μm to 20 μm, and the scanning speed of the laser light may be, for example, 500 mm / s to 5000 mm / s. The intensity of the laser light (intensity at the irradiated surface) may be, for example, 5 W to 200 W.

[0058] (Cutting process) Next, an opening 32 is formed by cutting a portion of the edge 35a that was not cut by laser irradiation (parts P1 and P2 in this embodiment). As a result, a labeled container 10 is manufactured in which an opening 32 leading to a recessed portion 2 is formed in the label 3, as shown in Figure 1. For example, parts P1 and P2 are torn off by moving the area to be removed 35 that has not been removed from the label 3 in a direction away from the label 3. For example, parts P1 and P2 are torn off by sucking the area to be removed 35 or by adsorbing the area to be removed 35 and moving it in the above direction. Alternatively, for example, a consumer may tear off parts P1 and P2 by pulling the area to be removed 35. Alternatively, for example, parts P1 and P2 may be torn off by bringing a roller or the like into contact with the area to be removed 35 and moving the area to be removed 35 in the tangential direction of its surface.

[0059] [Examples] Next, the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction was determined by changing the thickness of the label and the recycled material content. Furthermore, when a laser beam was shone on the labels with the changed thickness and recycled material content in an endless trajectory, the condition of the area to be removed was confirmed.

[0060] Figure 9 is a table showing an example of the results for label thickness and recycled material content, comparing the ratio of longitudinal tear strength to transverse tear strength and the condition of the removal area. The longitudinal direction is also called the machine direction (MD), and the MD tear strength in Figure 9 refers to the tear strength in the longitudinal direction. The transverse direction is the direction perpendicular to the machine direction and is also called the transverse direction (TD). The TD tear strength in Figure 9 shows the tear strength in the transverse direction.

[0061] The resin constituting the recycled material used in the base material 31 of the labels 3 in Examples 1 to 3 is PET resin derived from PET bottles. The resins other than the PET resin constituting the base material 31 in Examples 1 to 3 are modified PET with shrinkability, which is a resin suitably used for shrink labels. As shown in Figure 9, Example 1 is a label 3 (base material 31) containing 5% by weight of recycled material, and the thickness of the label 3 is 20 μm. Examples 2 and 3 are labels 3 (base material 31) containing 25% by weight of recycled material. The thickness of the label 3 in Example 2 is 30 μm, and the thickness of the label 3 in Example 3 is 40 μm. On the other hand, Comparative Examples 2 and 3 are labels that do not contain recycled material. The thickness of the label in Comparative Example 2 is 30 μm, and the thickness of the label in Comparative Example 3 is 40 μm.

[0062] Tear strength was measured according to the measurement method conforming to JIS K 7128-1. • Number of measurements n: n=5 in both the longitudinal and transverse directions; • Equipment used: Shimadzu Autograph (AG-X 500N); • Measurement environment: Room temperature (around 25°C, humidity 40-60%); • Specimen shape: 50 mm longitudinally, 150 mm transversely. A slit was made in the center of the longitudinal direction, 75 mm from the edge; • Measurement method: A tear test was conducted with a distance of 75 mm between the chucks. The "tear force" was defined as the average value of the tear load over 50 mm, excluding the first 20 mm and the last 5 mm before the end of tearing, and calculated using the following formula: Tear strength = Tear force of the specimen (N) / Thickness of the specimen (mm).

[0063] Furthermore, an ML-Z9500 (manufactured by Keyence) laser was used to cut a portion of the label that was attached to the container in a heat-shrunk state. The "40% laser output" and "70% laser output" shown in Figure 9 are values ​​when the laser light intensity of 80 (W) is set to 100%. The wavelength of the laser light was 10.6 μm, and the scanning speed was 2000 mm / s.

[0064] Figure 10 shows an example of the state of the removal target area 35 in a label 3 that has been heat-shrunk and attached to a container 1. Reference numerals 201 and 202 in Figure 10 indicate the state in which, after irradiation with laser light, the removal target area 35 is connected to other areas 36 of the label 3 via its edge 35a in the upper and lower regions of the removal target area 35. Reference numeral 201 indicates the state in which several connections (for example, about two or three) are observed in a relatively narrow area in both the upper and lower regions. Reference numeral 202 indicates the state in which more connections are observed over a wider area than in the state of reference numeral 201 in both the upper and lower regions. Reference numeral 203 in Figure 10 indicates the state in which the removal target area 35 falls off (detaches) due to irradiation with laser light alone, and an opening 32 is formed.

[0065] Figure 11 shows the X-X cross-section (second cross-section, see Figure 10) and the Y-Y cross-section (first cross-section, see Figure 10) when the label 3 of Example 3 is irradiated with laser light in an endless manner.

[0066] In Figure 9, the state of reference numeral 201 is referred to as "connected vertically," the state of reference numeral 202 is referred to as "connected vertically (over a wide area)," and the state of reference numeral 203 is referred to as "detached." The states of Comparative Examples 2 and 3 will also be explained with reference to Figure 10.

[0067] As shown in Figure 9, in the label 3 of Example 1 (containing 5% recycled material), the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction was 24.5. When this label 3 was continuously irradiated with a laser beam at 40% laser power, it was found that it became "connected vertically (over a wide area)" as shown by reference numeral 202 in Figure 10.

[0068] Furthermore, in the labels 3 of Examples 2 and 3 (containing 25% recycled material), the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction was 42.6 and 48.1, respectively. When each of the labels 3 of Examples 2 and 3 was irradiated with a laser beam at 70% laser power in an endless manner, it was found that both of the labels 3 of Examples 2 and 3 became "connected vertically" as shown by reference numeral 201 in Figure 10. As also shown in Figure 11, in Example 3, when the laser beam was irradiated, the edge 35a of the removal target area 35 was cut in the second cross-section (see reference numeral 301), whereas in the first cross-section, the edge 35a was not cut (see reference numeral 302).

[0069] On the other hand, for the labels of Comparative Examples 2 and 3 (without recycled material), the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction was 21.3 and 10.7, respectively. When each of the labels of Comparative Examples 2 and 3 was continuously irradiated with laser light at 70% laser power, it was found that both of the labels of Comparative Examples 2 and 3 "detached" as shown by reference numeral 203 in Figure 10.

[0070] (Discussion) From the above, it was found that when a laser beam is continuously irradiated onto the label, the label 3 containing recycled material does not have a portion of the edge 35a of the removal target area 35 (parts P1 and P2 in this example) cut off by laser beam irradiation alone. Therefore, by using the label 3 containing recycled material as the label for the labeled container 10, the possibility of the removal target area 35 falling off in the manufacturing line can be reduced.

[0071] Furthermore, when using a label 3 containing recycled material, there is little possibility that the area to be removed 35 will fall off even if laser light is continuously irradiated along the edge 35a of the area to be removed 35. Therefore, laser light can be continuously irradiated to form the opening 32.

[0072] As shown in Figure 11, the thickness of the edge 35a that was not cut by the laser beam irradiation (the thickness of the portion labeled "35a (P1)" in reference numeral 302) is thinner than the thickness of the edge 35a that was cut by the laser beam irradiation (the thickness T2 of the second edge 33b in reference numeral 301). Therefore, the thickness of the part of the edge 35a that was not cut by the laser beam irradiation (the part that is torn off) is thinner than the thickness of the part where the start and end positions are misaligned (the part that is torn off) that would be formed if the laser beam were not irradiated endlessly. Consequently, the possibility of burrs or tears occurring when a part of the edge 35a is torn off can be reduced. In other words, because the label 3 contains recycled material, it is possible to irradiate it with laser beam endlessly, which reduces the possibility of burrs occurring on the edge 33 of the opening 32 or tears occurring from the edge 33 toward the region 36 (see Figure 10).

[0073] In this way, by using the label 3 which contains recycled material, the possibility of large burrs or tears occurring and impairing the product value (aesthetics) of the labeled container 10 can be reduced. In addition, the possibility of consumers experiencing an unpleasant texture due to burrs when using the labeled container 10 can be reduced.

[0074] Furthermore, in Examples 1 to 3, the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction of the label 3 is 24 or more. In this case, the area to be removed 35 is "connected vertically (over a wide area)" or "connected vertically". Therefore, when the above ratio is 24, it can be said that a portion that is not cut by laser irradiation can be formed at the edge 35a of the area to be removed 35. This state is thought to be due to the hardening of the label containing the recycled material.

[0075] In particular, in Examples 2 and 3 (when the above ratio is 40 or more), the area to be removed 35 is "connected vertically," which reduces the amount of material that is not cut by laser irradiation. Therefore, the possibility of burrs being generated can be further reduced, and the area to be removed 35 can be removed more easily.

[0076] Furthermore, regardless of the thickness of the label, the larger the above ratio, the greater the tear strength in the longitudinal direction compared to the tear strength in the transverse direction. And the greater the tear strength, the more difficult it is for the label to be cut by laser irradiation. In the cases of Examples 1 to 3 (when the above ratio is 24 or more), the tear strength in the longitudinal direction is relatively large, so as shown by reference numerals 201 and 202 in Figure 10, portions P1 and P2 that are not cut by the laser are formed in the upper and lower regions of the removal target area 35.

[0077] For example, if the portion that is not cut by the laser beam is formed in an area other than the upper and lower regions of the area to be removed 35, the area to be removed 35 may sag due to its own weight. In this case, it becomes difficult to perform suction or other methods on the area to be removed 35. In other words, it becomes difficult to tear off the portion that is not cut. On the other hand, if the portion that is not cut is formed in the upper and lower regions of the area to be removed 35, the possibility of the area to be removed bending due to its own weight can be reduced. Therefore, the area to be removed 35 is easier to remove. Also, as shown in Examples 1 to 3, if the tear strength in the longitudinal direction is sufficiently greater than the tear strength in the transverse direction (the above ratio is 24 or more), it is possible to tear it in the transverse direction while reducing the possibility of unintended tears in the longitudinal direction when tearing it off.

[0078] Furthermore, with the same laser output intensity, the greater the tear strength, the less likely the label is to be cut. For example, in Examples 2 and 3, a portion of the edge 35a of the removal area 35 is not cut and does not fall off, whereas in Comparative Examples 2 and 3, the removal area 35 falls off. Therefore, in the label 3 containing recycled material, even with a laser output that would cause the removal area 35 to fall off in a label without recycled material, a portion of the edge 35a is not cut, allowing the laser output to be increased compared to when cutting a label without recycled material. In other words, in the label 3 containing recycled material, even with an increased laser output, it is possible to prevent a portion of the edge 35a (specifically portions P1 and P2) from being cut by laser irradiation. This effect is at least achieved when the label 3 containing recycled material and the label without recycled material have similar thicknesses.

[0079] Furthermore, by increasing the output of the laser beam, stable mass production of the labeled container 10 becomes possible, and the possibility of burrs forming on the edges 33 of the opening 32 cut by the laser beam irradiation can be further reduced. The possibility of burrs forming can be reduced regardless of the design attached to the label 3.

[0080] However, if the recycled material content is relatively low, as in Example 1, irradiating the label 3 with a laser beam of the output power shown in Examples 2 and 3 may cause the removal target area 35 to fall off due to the laser beam irradiation. Therefore, the laser beam output is adjusted according to the recycled material content. Specifically, the laser beam output is set to be lower the lower the recycled material content. For example, the laser beam output set in Example 1 is set lower than the laser beam output set in Examples 2 and 3.

[0081] In this way, by optimizing the output of the laser beam, the edge 35a of the area to be removed 35 can be cut with the laser beam without cutting off any part of the edge 35a of the area to be removed 35, regardless of the amount of recycled material contained in the substrate 31. As a result, even if the label 3 containing recycled material is continuously irradiated with laser beam, the possibility of the area to be removed 35 falling off can be reduced. Furthermore, a label 3 can be provided with a low possibility of burrs or tears and with the opening 32 formed as designed. Therefore, it is possible to improve the productivity of the label 3 while maintaining the commercial value of the label 3.

[0082] Furthermore, the results from Examples 1 to 3 show that the above-described effects are achieved when the recycled material content is 5% by weight or more. In other words, considering that the material, thickness, and laser output of the recycled material can be adjusted as appropriate, it is reasonable to say that the above-described effects are achieved when the recycled material content is, for example, 1% by weight or more.

[0083] Furthermore, as shown in Figures 8 and 10, portions P1 and P2 have a thickness T1 of the first edge 33a of the opening 32 that appears in the first cross-section, or a value close to that thickness T1, as shown in Figure 11. As described above, this thickness T1 is thinner than the thickness T2 of the second edge 33b of the opening 32 that appears in the second cross-section. Therefore, portions P1 and P2 can be easily torn off. Consequently, the possibility of burrs forming on the edge 33 after portions P1 and P2 have been torn off can be reduced.

[0084] Furthermore, by increasing the output of the laser light, the thickness T1 can be further reduced. Therefore, in this case, the possibility of burrs forming on the edges 33 after tearing off portions P1 and P2 can be further reduced.

[0085] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

[0086] For example, the embodiment described above explains a case in which a part of a label containing recycled material is cut by irradiating the label with laser light in an endless trajectory. However, it is not limited to this, and it is not always necessary to irradiate the label with laser light in an endless trajectory in order to cut a part of a label containing recycled material. In other words, the start position and end position of the laser light irradiation may be offset.

[0087] When cutting labels containing recycled materials, a higher laser output can be used compared to labels without recycled materials. Therefore, labels containing recycled materials are easier to cut into a predetermined shape. Consequently, even if the laser beam is irradiated in a way that offsets the start and end positions, stable production of labels containing recycled materials becomes possible.

[0088] Furthermore, even if the laser beam is irradiated so that the starting and ending positions are offset, the label containing recycled material can be cut by increasing the laser beam output as described above, thus reducing the possibility of burrs compared to labels that do not contain recycled material. Also, even if burrs do occur, they can be made smaller compared to labels that do not contain recycled material.

[0089] Furthermore, in labels containing recycled materials, even if the laser beam is irradiated so that the start and end positions are offset, a slight stringing is formed in the upper and lower regions of the laser beam's trajectory. This stringing refers to the portion of the laser beam's trajectory that was not cut by the laser beam (part of the edge of the area to be removed). This stringing allows the area to be removed to be supported, preventing it from falling, even at locations other than the connection point between the area to be removed and other parts of the label, which is formed by the offset between the start and end positions. Therefore, the width of the connection point between the start and end positions can be reduced to the absolute minimum.

[0090] Furthermore, by starting and ending laser irradiation in the upper region of the area to be removed, it is possible to connect the area to be removed with other regions through stringing, not only in the upper region that was intentionally not cut, but also in a part of the lower region of the area to be removed. This reduces the possibility of the area to be removed, while connected to the label, fluttering around.

[0091] 1 Container 3 Label 10 Labeled container 31 Base material 32 Opening 33a First edge 33b Second edge T1 Thickness of the first edge T2 Thickness of the second edge

Claims

1. A labeled container comprising a container and a label attached to the container in a heat-shrinked state, wherein the circumferential direction of the container is the transverse direction of the label, and the direction perpendicular to the transverse direction is the vertical direction of the label, the label comprises a base material containing polyester resin recycled from PET (polyethylene terephthalate) products, which is heat-shrinkable at least in the transverse direction, and the label has an opening formed by cutting a part of the label when a laser beam is irradiated onto the label.

2. The labeled container according to claim 1, wherein the label contains 1% by weight or more of the polyester resin.

3. The labeled container according to claim 1 or 2, wherein the thickness of the first edge of the opening that appears in the first cross-section when the label is cut along the vertical direction is thinner than the thickness of the second edge of the opening that appears in the second cross-section when the label is cut along the horizontal direction.

4. The labeled container according to claim 1, wherein the ratio of the tear strength in the longitudinal direction to the tear strength in the transverse direction of the label is 24 or more.

5. A method for manufacturing a labeled container, comprising a container and a label to be attached to the container, wherein, with the label attached to the container, the circumferential direction of the container is the transverse direction of the label, and the direction perpendicular to the transverse direction is the vertical direction of the label, the label comprises a base material having heat shrinkability in at least the transverse direction and containing polyester resin recycled from PET (polyethylene terephthalate) products, the method comprising: an attachment step of attaching the label to the container by heat shrinking the label; an irradiation step of irradiating the edge of the area to be removed from the label with laser light while the label is attached to the container; and a cutting step of forming an opening by cutting a part of the edge that was not cut by the irradiation of the laser light.

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