How to remove the printed layer from a cylindrical label

Abstract

To allow for removing a printing layer without leaving any residue.SOLUTION: A cylindrical label (1A) has a seaming portion (121) with a non-sealed area (121b) where ends of a heat-shrinkable film (101) are not sealed together and a liquid for removing a printing layer (111) of the heat-shrinkable film (101) is flowed. The non-sealed area (121b) puts the inside and the outside of the cylindrical label (1A) into communication in an overlapping portion (120).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cylindrical label for packaging a container to be packaged, and a method for removing a printed layer from the cylindrical label. [Background technology]

[0002] Conventionally, as a film packaging body in which a heat-shrinkable film is wound around a product in a cylindrical shape and the heat-shrinkable film is heated to shrink the product, there is, for example, a heat-shrinkable tubular label disclosed in Patent Document 1. This heat-shrinkable tubular label is attached to the product, and the product is packaged by heating the heat-shrinkable label. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2020-76837 Summary of the Invention [Problem to be solved by the invention]

[0004] Typically, the cylindrical label is printed with ink with the name of the product to be packaged in the cylindrical label, text describing the product, an illustration that evokes the image of the product, and the like.

[0005] On the other hand, in recent years, there has been a demand for recycling plastics in consideration of the environment. For example, cylindrical labels made of plastic film are deinked to remove printed letters and illustrations, and then recovered as transparent plastic film fluff. Development is underway to reuse these plastics in labels, bottles, and other plastic products.

[0006] A cylindrical label is a label formed into a cylindrical shape by overlapping the ends of plastic films at an overlapping portion (center seal portion), and letters and illustrations may also be printed in ink on the center seal portion. For example, as shown in FIG. 13 , a printed layer 402 with letters and illustrations printed in ink may be formed on the inner circumferential surface 401c of a plastic film 401. This printed layer 402 is formed up to just before the center seal portion 420 on the end 401a side of the plastic film 401, and is formed up to an area including an inner residue 401d on the end 401b side of the plastic film 401. Here, the inner residue 401d is the non-center-sealed area on the end 401b side of the inner plastic film 401 in the center seal portion 420. In other words, the inner residue 401d exists to prevent the solvent (adhesive) from spilling out toward the inside of the tube when sealing the ends 401a and 401b of the plastic film 401 with a solvent or the like.

[0007] Furthermore, providing a printed layer 402 in the center seal portion 420 reduces the seal strength. Therefore, as described above, by providing inner scrap 401d on the end 401b side of plastic film 401 so that the printed layer 402 on the end 401a side of plastic film 401 overlaps the printed layer 402 on the end 401b side, the continuity of the printed layer 402 can be ensured. Furthermore, since there is no need to provide a printed layer 402 in the center seal portion 420, the seal strength of the center seal portion 420 can also be ensured. Therefore, inner scrap 401d is an area that is left unsealed after sealing, leaving a margin on the end 401b side of the inner plastic film 401, and is an area that is provided to ensure both the continuity of the printed layer 402 and the seal strength of the plastic center seal portion 420.

[0008] However, when printed layer 402 can be removed with a liquid, printed layer 402 can be removed to some extent by the liquid for removing printed layer 402, but cannot be completely removed. In particular, printed layer 402 formed on plastic film 401 facing inner residue 401d of plastic film 401 in center seal portion 420 may not be sufficiently removed. This is because the liquid for removing printed layer 402 has difficulty reaching end 403 of printed layer 402 near center seal portion 420.

[0009] Thus, if the printed layer of the cylindrical label is not sufficiently removed during the recycling process, the ink contained in the remaining printed layer will become contaminated as foreign matter into the recycled plastic product, causing problems such as fisheyes in the plastic product or the contaminated ink causing unintended coloring of the plastic product.

[0010] An object of one aspect of the present invention is to provide a cylindrical label that can prevent a portion of the printed layer from remaining and being unable to be removed. [Means for solving the problem]

[0011] In order to solve the above problems, one embodiment of the present invention provides a tubular label formed into a tubular shape by overlapping the ends of a heat-shrinkable film at a seaming portion, wherein a printed layer that can be removed with a liquid is formed on the surface of the heat-shrinkable film inside the tube of the tubular label, and the seaming portion includes a non-sealed region through which a liquid can be passed to remove the printed layer where the heat-shrinkable film is not sealed together, and a sealed region where the heat-shrinkable film is sealed together, and the non-sealed region is connected from inside the tube of the tubular label to outside the tube.

[0012] According to the above configuration, the non-sealed area communicates from the inside of the cylindrical label to the outside of the cylindrical label, allowing the liquid for removing the printed layer to flow through the non-sealed area of ​​the seaming section to the liquid-removable printed layer formed on the surface of the heat-shrinkable film inside the cylindrical label. In this way, when the liquid for removing the printed layer flows into the cylindrical label from the non-sealed area of ​​the seaming section, the liquid sufficiently reaches the printed layer formed inside the cylindrical label, ensuring reliable removal of the printed layer. This prevents a portion of the printed layer from remaining on the cylindrical label due to inability to remove it, preventing problems (such as fisheyes or unwanted coloration) caused by a portion of the printed layer remaining when the collected cylindrical label is reused.

[0013] In addition, in the cylindrical label of aspect 2 of the present invention, in aspect 1, the portion where the ends of the heat-shrinkable film are overlapped includes the seaming portion and a non-seaming portion formed adjacent to the seaming portion and where the heat-shrinkable films face each other without being sealed, and the printing layer is formed on at least one of the facing surfaces of the heat-shrinkable films in the non-seaming portion.

[0014] According to the above configuration, the printed layer is formed on at least one of the opposing surfaces of the heat-shrinkable films in the non-seaming portion, so that the printed layers on the end sides of the heat-shrinkable films on both sides of the seaming portion can be overlapped in the non-seaming portion, thereby ensuring the continuity of the printed layers.

[0015] Furthermore, in a cylindrical label according to a third aspect of the present invention, in the first or second aspect, the printed layer is an alkali-soluble printed layer, and the liquid is an alkaline aqueous solution.

[0016] According to the above configuration, when the cylindrical label is collected and reused, the printed layer can be removed with an alkaline aqueous solution.

[0017] Furthermore, a method for removing a printed layer according to aspect 4 of the present invention is a method for removing a printed layer that can be removed with a liquid formed inside a tube from a tubular label formed by overlapping ends of a heat-shrinkable film and joining the ends at a seaming section, wherein the seaming section includes a non-sealed area where the heat-shrinkable film is not sealed together and a sealed area where the heat-shrinkable film is sealed together, the non-sealed area connecting the inside of the tubular label to the outside of the tube, and the method includes a step of immersing the heat-shrinkable film that includes at least the non-sealed area in a liquid for removing the printed layer to remove the printed layer.

[0018] According to the above configuration, the printed layer is removed by flowing a liquid for removing the printed layer into the non-sealed area of ​​the heat-shrinkable film, which includes at least a non-sealed area. In other words, the non-sealed area is connected from the inside of the cylindrical label to the outside of the cylindrical label, allowing the liquid for removing the printed layer to flow through the non-sealed area to the printed layer inside the cylindrical label. Once the liquid for removing the printed layer flows into the cylindrical label, it is sufficiently distributed over the printed layer, ensuring reliable removal of the printed layer. This prevents portions of the printed layer from remaining unremoved, preventing problems (such as fisheyes and unwanted coloration) caused by the remaining printed layer when the collected cylindrical labels are reused.

[0019] In this way, if the printed layer is removed by flowing a liquid that removes the printed layer into the non-sealed area of ​​the seaming section, the heat-shrinkable film is not limited to being in a cylindrical state, and the printed layer can be removed even when the cylindrical label is peeled off from a product (e.g., a bottle) and the cylindrical label is separated into sheets. [Effects of the Invention]

[0020] According to one aspect of the present invention, the printed layer of the cylindrical label can be removed without leaving any residue. [Brief explanation of the drawings]

[0021] [Figure 1]FIG. 1 is a perspective view showing a schematic configuration of an original sheet according to an embodiment of the present invention. [Figure 2] 2 is a front view of the overlapping portion of the tubular label obtained from the raw material shown in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] FIG. 4 is an enlarged view of the overlapping portion shown in FIG. 3. [Figure 5] 3 is an explanatory diagram for explaining the positions where a sealed region and a non-sealed region are formed in the seaming portion shown in FIG. 2.

[0023] FIG. [Figure 6] FIG. 2 is a schematic perspective view of a sealing device. [Figure 7] 7 is a schematic diagram of an anvil portion of the sealing device shown in FIG. 6. FIG. [Figure 8] 8 is a schematic diagram of a protrusion formed on the anvil shown in FIG. 7. FIG. [Figure 9] FIG. 10 is an explanatory diagram of an ultrasonic seal. [Figure 10] 3 is an explanatory diagram for explaining packaging of a container with the cylindrical label shown in FIG. 2.

[0023] FIG. [Figure 11] FIG. 10 is a diagram showing an example of an anvil pattern in a seaming portion. [Figure 12] 10A and 10B are diagrams showing other examples of anvil patterns in seaming portions. [Figure 13] FIG. 1 is a schematic cross-sectional view of an overlapping portion of a typical cylindrical label. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, an example of a cylindrical label according to the present invention obtained from a raw sheet will be described. However, the following description is merely an example of a cylindrical label according to the present invention, and the technical scope of the present invention is not limited to the illustrated example.

[0023] <Outline of the raw material> FIG. 1 shows a schematic configuration of a raw roll 1 according to this embodiment, where reference numeral 1001 is a perspective view of a heat-shrinkable film 101 constituting the raw roll 1, and reference numeral 1002 is a perspective view of the raw roll 1 obtained by overlapping the ends of the heat-shrinkable film 101.

[0024] The heat-shrinkable film 101 is a rectangular film as indicated by reference numeral 1001 in FIG. 1, and is, for example, flexible and heat-shrinkable at least in a direction perpendicular to the direction in which the overlapping portion 120 described below stretches (the circumferential direction when the heat-shrinkable film 101 is formed into a cylindrical shape). Any known film can be used as the heat-shrinkable film 101. Here, heat-shrinkable refers to the property of shrinking when heated to a predetermined temperature (for example, 70°C to 180°C). The heat-shrinkable film 101 has a heat shrinkage rate of 30% or more, preferably 50% or more, when immersed in 90°C hot water for 10 seconds.

[0025] As will be described later, heat-shrinkable film 101 has printed layer 111 formed thereon and is shaped like a tube with printed layer 111 on the inside. Therefore, a transparent substrate is preferred so that the printing of printed layer 111 on the inside of the tube can be seen from the outside of the tube. Heat-shrinkable film 101 may be a single layer or may have a structure in which multiple layers are laminated. The thickness of heat-shrinkable film 101 is about 15 μm to 100 μm, but is not limited to this range.

[0026] Examples of materials for the heat-shrinkable film 101 include resin compositions containing, as a main component, one or a mixture of two or more selected from polyester resins such as polyethylene terephthalate and polylactic acid, olefin resins such as polyethylene, polypropylene and cyclic olefin, polystyrene resins such as polystyrene, and thermoplastic resins such as vinyl chloride resins. The above-mentioned materials for the film substrate are merely examples and are not limited to these.

[0027] A first end 101a, which is one of both longitudinal edge portions of the heat-shrinkable film 101, and a second end 101b, which is the other of the both longitudinal edge portions, are overlapped as shown by reference numeral 1002 in Fig. 1, and the resulting overlapped portion 120 is sealed to form a tubular raw web 1. This tubular raw web 1 is a raw web to be cut to the size of the container (product) to be packaged to obtain a plurality of tubular labels 1A (Fig. 2).

[0028] <Explanation of overlapping parts> Fig. 2 is a front view of the overlapping portion 120 of the cylindrical label 1A obtained by cutting the raw web 1 shown in Fig. 1 to a predetermined length. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 4 is an enlarged view of region B in Fig. 3. For ease of explanation, the printed layer 111 (Fig. 4) in the overlapping portion 120 is omitted in Figs. 2 and 3.

[0029] The overlapping portion 120 of the cylindrical label 1A is not entirely sealed, but has a seaming portion 121 and a non-seaming portion 122, as shown in FIG. 2 . The seaming portion 121 includes a sealed region 121a where the heat-shrinkable films 101 are sealed together, and a non-sealed region 121b where the heat-shrinkable films 101 are not sealed together. The seaming portion 121 is a strip-shaped region of a predetermined width in the overlapping portion 120. The non-seaming portion 122 is a region formed adjacent to the seaming portion 121 and is also a strip-shaped region of a predetermined width. The non-seaming portion 122 is a region where the heat-shrinkable films 101 face each other in an unsealed state. In other words, the non-seaming portion 122 is a region where the region on the end side of the heat-shrinkable film 101 that will be on the inside when the heat-shrinkable film 101 is shaped like a tube faces the region on the end side of the heat-shrinkable film 101 that will be on the outside.

[0030] In FIG. 2, the sealed area is the area within the circle indicated by the dotted line. Not all sealed areas are labeled with the symbol 121a in order to clarify the illustration. The seaming portion 121 includes a non-sealed area 121b, which forms a space within the seaming portion 121. In other words, the non-sealed area 121b forms a space. This space communicates from the inside of the cylindrical label 1A to the outside. This point will be explained below.

[0031] As shown in FIG. 3, the non-sealed area 121b is an area where the opposing surfaces of the first end 101a and the second end 101b are not sealed. That is, the non-sealed area is the area where the opposing surfaces of the first opposing surface 101c on the first end 101a side and the second opposing surface 101d on the second end 101b side are not sealed. In this way, the non-sealed area 121b is an area where the first opposing surface 101c and the second opposing surface 101d are not welded together, allowing liquid to pass through. The non-sealed area 121b is connected from the inner end 102 to the outer end 103 of the seaming portion 121. That is, the non-sealed area 121b is connected from the inside to the outside of the cylindrical label 1A at the seaming portion 121.

[0032] The sealed area 121a in the seaming portion 121 is ultrasonically sealed. Thus, ultrasonic sealing (ultrasonic sealing) generates frictional heat between the opposing surfaces (first opposing surface 101c and second opposing surface 101d) of the heat-shrinkable film 101 to achieve sealing. Furthermore, ultrasonic sealing achieves sealing without the use of solvents or adhesives, resulting in the following advantages: By eliminating the use of solvents or adhesives, the environmental impact is reduced. Furthermore, by eliminating the use of solvents or adhesives, the amount of material constituting the raw web 1 is reduced, thereby reducing the environmental impact and facilitating recycling of the tubular label 1A obtained from this raw web 1. Moreover, ultrasonic sealing allows the sealed area 121a to be easily formed in a desired shape and position simply by changing the shape of the anvil roller. Furthermore, ultrasonic sealing allows for faster production of the raw web 1 than heat sealing methods using hot plates.

[0033] Furthermore, ultrasonic sealing does not use a solvent to connect the heat-shrinkable films 101 together, so it is possible to use heat-shrinkable films 101 made of a material that does not dissolve in solvents, which increases the freedom of selection of heat-shrinkable films 101 that can be used for the cylindrical label 1A. Details of ultrasonic sealing will be described later.

[0034] The heat-shrinkable film 101 is printed with the name of the product (packaged item) to be packaged in the tubular label 1A, text such as a description of the product, illustrations related to the product, etc. For example, as shown in FIG. 4 , a printed layer 111 with text, illustrations, etc. printed with ink is formed on the inner peripheral surface 101e of the heat-shrinkable film 101 (the surface on the side where the heat-shrinkable film 101 comes into contact with the product). The printed layer 111 is preferably an alkali-soluble printed layer that can be removed with a liquid and an alkaline aqueous solution. Specifically, the printed layer 111 contains an alkali-soluble resin component. When the printed layer 111 is formed with multiple inks and has a layered structure, it is sufficient that at least the layer in contact with the base material (heat-shrinkable film 101) is alkali-soluble. Furthermore, because the printed layer 111 is liquid-removable and contains an alkali-soluble resin component, the liquid for removing the printed layer 111 is preferably an alkaline aqueous solution. In this case, the alkaline aqueous solution is, for example, an alkaline aqueous solution containing an alkaline substance, and examples of the alkaline substance include sodium hydroxide, potassium hydroxide, ammonia, etc. The alkaline substance is contained in the aqueous solution in an amount of, for example, about 0.1 to 10% by weight. The aqueous solution may be used at room temperature or heated, and if heated, it is preferably about 65°C to 90°C.

[0035] The printed layer 111 is not formed on the entire inner circumferential surface 101e of the heat-shrinkable film 101. Specifically, as shown in Fig. 4, in the seaming portion 121 of the overlapping portion 120, the printed layer 111 is not formed on the first end 101a side of the heat-shrinkable film 101, and the printed layer 111 is formed only on the second end 101b side of the heat-shrinkable film 101. On the other hand, in the non-seaming portion 122 of the overlapping portion 120, the printed layer 111 is formed on both the first end 101a side and the second end 101b side of the heat-shrinkable film 101. This is because the seaming portion 121 is a portion to be sealed, and if the printed layer 111 is formed on the sealed portion (the first end 101a side), the seal strength cannot be ensured. In contrast, in the non-sealed portion 122, an unsealed inner residue 101f is formed on the second end 101b side of the heat-shrinkable film 101, and this inner residue 101f simply faces the heat-shrinkable film 101 on the first end 101a side without being sealed, so that the printed layer 111 can be formed on both the first end 101a side and the second end 101b side of the heat-shrinkable film 101. This ensures the sealing strength of the heat-shrinkable film 101 and also ensures the continuity of the letters and illustrations printed on the heat-shrinkable film 101.

[0036] In addition, the printing layer 111 may be formed not only on the inner surface 101e of the heat-shrinkable film 101 but also on the outer surface, or on both the inner surface 101e and the outer surface, as long as the continuity of letters, illustrations, etc. can be ensured in the tubular label 1A, except for the opposing surfaces of the heat-shrinkable films 101 in the overlapping portion 120.

[0037] Furthermore, as described above, the printed layer 111 contains an alkali-soluble resin component. Therefore, the printed layer 111 can be removed by immersing the printed layer 111 in an alkaline aqueous solution. When considering the removal of the printed layer 111, the components of the printed layer 111 are not limited to components that can be removed with an alkaline aqueous solution, but may also be components that can be removed with other chemical solutions. Details regarding the removal of the printed layer 111 will be described later.

[0038] <Details of sealed and non-sealed areas> Fig. 5 is an explanatory diagram for explaining the positions where the sealed area 121a and the non-sealed area 121b are formed in the seaming portion 121. For ease of explanation, Fig. 5 shows the second opposing surface 101d of the heat-shrinkable film 101 in the seaming portion 121, and omits the first opposing surface 101c (Fig. 3).

[0039] In the seaming portion 121, a plurality of sealed regions 121a are formed, and the sealed regions 121a and the non-sealed regions 121b are alternately arranged along the circumferential direction, as shown in FIG. 5. Here, the circumferential direction refers to the direction in which the tubular label 1A mainly shrinks when attached to a container. Here, because the tubular label 1A is cylindrical, shrinkage of the tubular label 1A occurs not only in the circumferential direction but also in the axial direction. However, since the axial shrinkage is slight, the main direction of shrinkage is the circumferential direction. As such, the tubular label 1A is made of a heat-shrinkable film 101, and since it is the heat-shrinkable film 101 that actually shrinks, the direction in which the tubular label 1A shrinks will hereinafter be described as the direction in which the heat-shrinkable film 101 shrinks (the shrinkage direction).

[0040] It is preferable that the non-sealed region 121b in the seaming portion 121 does not coincide with any of the shrinkage directions (circumferential direction or axial direction) of the heat-shrinkable film 101. For this purpose, a sealed region that breaks the continuity of the non-sealed region 121b in the shrinkage direction needs to be present in the shrinkage direction of the heat-shrinkable film 101.

[0041] Here, since the direction in which heat-shrinkable film 101 mainly shrinks is the circumferential direction, it is preferable that sealed areas 121a and non-sealed areas 121b are alternately arranged along the circumferential direction indicated by the arrows in FIG.

[0042] By arranging the sealed region 121a and the non-sealed region 121b in the seaming portion 121 in this manner, the non-sealed region 121b is not formed continuously in the circumferential direction from the second end 101b to the first end 101a. In other words, the sealed region 121a is always formed between the second end 101b and the first end 101a in the circumferential direction, and the non-sealed region 121b does not have a continuous shape in the direction that coincides with the main shrinkage direction (circumferential direction) of the heat-shrinkable film 101. This reduces the possibility of wrinkling the heat-shrinkable film 101 when it shrinks, for example, during ultrasonic sealing of the seaming portion 121 or when the heat-shrinkable film shrinks when packaging it in a container. Furthermore, it reduces the possibility of the sealed region 121a peeling off due to shrinkage of the non-sealed region 121b when the heat-shrinkable film 101 shrinks.

[0043] If the energy applied when sealing the heat-shrinkable film 101 is too large, the boundary between the sealed region 121a and the non-sealed region 121b may be prone to tearing. This may result in so-called edge tearing. If edge tearing occurs, and the sealed region 121a is continuous in the circumferential direction in the seaming portion 121, the edge tearing will propagate from the second end 101b to the first end 101a, causing a large tear and damaging the aesthetic appearance of the package. However, as shown in FIG. 5, if the sealed region 121a is not continuous in the circumferential direction from the second end 101b to the first end 101a, even if edge tearing occurs at the boundary between the sealed region 121a and the non-sealed region 121b, the resulting edge tearing can be prevented from propagating from the second end 101b to the first end 101a. This prevents tearing that would significantly damage the aesthetic appearance of the package.

[0044] In the seaming portion 121, the sealed regions 121a and the non-sealed regions 121b are not only alternately arranged in the circumferential direction. That is, each sealed region 121a is formed in the same shape as the other sealed regions 121a, and the non-sealed regions 121b are formed in a substantially lattice shape (the shape indicated by the dashed lines in the figure) by connecting the spaces between the multiple sealed regions 121a, as shown in Fig. 5. By forming the non-sealed regions 121b in a lattice shape in this way, it is possible to reliably remove liquid between the heat-shrinkable film 101 and the container.

[0045] Furthermore, the non-sealed region 121b functions as a flow path for a liquid (alkaline liquid) that removes the printed layer 111. In other words, the non-sealed region 121b functions as a flow path for flowing the liquid that removes the printed layer 111 in order to remove the printed layer 111 in the vicinity of the seaming portion 121.

[0046] Therefore, the non-sealed area 121b may have any shape as long as it functions as a flow path that communicates from the inside to the outside of the cylindrical label 1A in the seaming portion 121. Other examples of the shape of the non-sealed area 121b will be described later.

[0047] Although the sealing areas 121a shown in FIG. 5 are substantially circular, they are not limited to a circular shape as long as they are the same shape. The shape of the sealing areas 121a can be freely changed by changing the shape of the ambi-roller of the sealing device. Here, if the shapes of the multiple sealing areas 121a are the same (circular), the force sealing the heat-shrinkable films 101 together can be made uniform and without bias in the seaming portion 121. This reduces the possibility of the sealing areas 121a peeling off.

[0048] The shapes and sizes of the sealing areas 121a do not have to be the same. For example, the shapes of the sealing areas 121a may be a mixture of squares and circles, and the sizes of the sealing areas 121a may be a mixture of large and small sizes.

[0049] <Explanation of ultrasonic seal> Fig. 6 is a schematic perspective view of sealing device 201. Fig. 7 is a schematic configuration diagram of anvil section 240 provided in sealing device 201 shown in Fig. 6. Fig. 8 is a schematic configuration diagram of protrusion section 241 of anvil section 240. Fig. 9 is an explanatory diagram of ultrasonic sealing. For ease of explanation, the print layer 111 formed on heat-shrinkable film 101 is omitted in Fig. 6.

[0050] 6, the sealing device 201 sandwiches the overlapping portion 120 of the heat-shrinkable film 101 between the ultrasonic oscillator 210 and the anvil 240 having a plurality of protrusions 241 formed thereon, thereby applying an appropriate pressure to the overlapping portion 120 and transmitting ultrasonic waves generated by the ultrasonic oscillator 210. As a result, the overlapping portion 120 is sealed by heat welding the heat-shrinkable films 101 together at the seaming portion 121 (see FIG. 2, etc.) by frictional heat.

[0051] Here, the entire area of ​​the seaming portion 121 is not sealed, but includes a sealed area 121a where the heat-shrinkable films 101 are sealed together, and a non-sealed area 121b where the heat-shrinkable films 101 are not sealed together. In other words, only in the area forming the sealed area 121a, the multiple protrusions 241 formed on the anvil part 240 come into contact with the heat-shrinkable film 101 so that frictional heat is generated by the ultrasonic waves of the ultrasonic oscillator 210.

[0052] As shown in Fig. 7, the anvil part 240 has a plurality of protrusions 241 formed on its surface 240a. As shown in Fig. 8, the protrusions 241 are each formed in a truncated cone shape. The shape of the protrusions 241 is not limited to the shape shown in Fig. 8, and may be cylindrical, rectangular, or the like, as long as the portion facing the ultrasonic oscillator 210 is flat.

[0053] When sealing is performed with the seaming portion 121 of the overlapping portion 120 sandwiched between the ultrasonic oscillator 210 and the anvil 240, the overlapping portion 120 is set between the ultrasonic oscillator 210 and the anvil 240, as shown by reference numeral 1091 in Fig. 9. At this time, the first opposing surface 101c and the second opposing surface 101d of the two heat-shrinkable films 101 in the set overlapping portion 120 are in close contact with each other (not yet welded).

[0054] Next, a predetermined pressure is applied to the seaming portion 121 of the overlapping portion 120 by the ultrasonic oscillator 210 and the anvil 240, and ultrasonic vibrations are applied to the heat-shrinkable film 101 from the ultrasonic oscillator 210. As a result, frictional heat is generated by the pressure and ultrasonic vibrations in the area of ​​the heat-shrinkable film 101 sandwiched between the ultrasonic oscillator 210 and the protrusions 241. This frictional heat heat-welds the portions of the first opposing surface 101c and the second opposing surface 101d that correspond to the protrusions 241. When the ultrasonic treatment is performed in this manner, the portions of the first opposing surface 101c and the second opposing surface 101d that correspond to the protrusions 241 are melted and crushed by the frictional heat, and the crushed, protruding portions are not welded and move toward the recessed portion between the protrusions 241. As a result, as shown by the symbol 1092 in Figure 9, in the seaming portion 121 of the overlapping portion 120, a sealed area 121a where the first opposing surface 101c and the second opposing surface 101d are heat-welded, and a non-sealed area 121b where the first opposing surface 101c and the second opposing surface 101d are not heat-welded are formed.

[0055] In this way, ultrasonic sealing by sealing device 201 applies ultrasonic waves while applying an appropriate pressure to heat-shrinkable film 101 at seaming portion 121 of overlapping portion 120, causing the overlapping portion (contacting portion) of heat-shrinkable film 101 to generate heat due to frictional heat and form a seal region 121a by thermal welding. The appropriate pressure and ultrasonic frequency in this case are not fixed values ​​but vary depending on conditions such as the material and thickness of heat-shrinkable film 101.

[0056] 7, the anvil part 240 has the protrusions 241 formed so that the regions where the protrusions 241 are not formed in the circumferential direction, i.e., the regions corresponding to the non-sealed regions 121b in the seaming part 121 of the overlapping part 120, are not continuous. By using the anvil part 240 having the protrusions 241 formed in this way, the non-sealed regions 121b in the seaming part 121 of the overlapping part 120 can be formed so that they do not extend in the direction that coincides with the main shrinkage direction (circumferential direction) of the heat-shrinkable film 101.

[0057] <Reusing cylindrical label 1A> FIG. 10 is an explanatory diagram illustrating packaging of a container with a tubular label 1A. For ease of explanation, the printed layer 111 is omitted from FIG. 10. As shown in FIG. 10, the tubular label 1A packages a container 301, which is the object of packaging. The tubular label 1A functions as a product label by wrapping the film attachment surface 301a of the container 301. By attaching the tubular label 1A to the container 301, a label molded product 3 can be formed in which the product label is attached to the container 301, as indicated by the right arrow in FIG. 10.

[0058] Furthermore, once the label molded body 3 has finished being used as a product, it is reused. When it is reused, the cylindrical label 1A is peeled off from the container 301 of the label molded body 3, and the container 301 and the cylindrical label 1A are separated and collected as shown by the left arrow in Fig. 10. Here, the collection of the cylindrical label 1A will be described.

[0059] The collected tubular labels 1A are, for example, heat-shrunk and then cut to a predetermined size. To remove the printed layer, the labels are placed in a container filled with alkaline solution and immersed in the alkaline solution. Since alkaline solution remains on the surface of the heat-shrinkable film 101 from which the printed layer has been removed, the alkaline solution is washed away with water. The heat-shrinkable film 101, now transparent and free of the printed layer and alkaline solution, is collected as transparent plastic film fluff or the like and recycled into recycled resin for reuse in labels, bottles, and other plastic products. Specifically, the collected tubular labels 1A (including the heat-shrinkable film 101 and the printed layer 111) are used as raw material, and by undergoing the process of removing the printed layer 111 from the raw material as described above, the heat-shrinkable film 101 from which the printed layer 111 has been removed can be collected and recycled into recycled resin for reuse in labels, bottles, and other plastic products.

[0060] If the printed layer of the tubular label 1A is not sufficiently removed, the ink contained in the remaining printed layer will become foreign matter and contaminate the recycled plastic product, causing various problems such as fish eyes and discoloration in the plastic product. Therefore, a method for sufficiently removing the printed layer of the tubular label 1A without leaving any residue will be described below with reference to Figure 4.

[0061] <Removal of printed layer> 4, in the cylindrical label 1A, on the first end 101a side of the heat-shrinkable film 101, the printed layer 111 is formed up to just before the sealed region 121a on the inner end 102 side of the non-seaming portion 122, and on the second end 101b side of the heat-shrinkable film 101, the printed layer 111 is formed up to an area including the inner residue 101f of the second end 101b in the non-seaming portion 122. Here, on the inner end 102 side of the non-seaming portion 122, the space toward the sealed region 121a of the seaming portion 121 is narrow, so that the liquid (here, an alkaline aqueous solution is used as an example, and hereinafter referred to as the alkaline liquid) for removing the printed layer (containing an alkali-soluble resin component) 111 may not reach just before the sealed region 121a, and part of the printed layer 111 may remain unremoved.

[0062] However, as described above, in the seaming portion 121, the non-sealed region 121b communicates from the inner end 102 to the outer end 103 of the seaming portion 121, and this communication portion functions as a flow path for the alkaline solution. Therefore, if the heat-shrinkable film 101, including at least the non-sealed region 121b, is placed in a container filled with alkaline solution and immersed in the alkaline solution, the alkaline solution flows into the tube from the non-sealed region 121b of the seaming portion 121. This allows the alkaline solution to sufficiently reach the printed layer 111 adjacent to the seaming portion 121. In other words, the alkaline solution is sufficiently spread throughout the space toward the sealed region 121a on the inner end 102 side of the non-seaming portion 122, ensuring reliable removal of the printed layer 111 in the space toward the sealed region 121a on the inner end 102 side of the non-seaming portion 122. Therefore, it is possible to sufficiently remove the printed layer 111 of the tubular label 1A without leaving any residue, so that when the collected tubular label 1A is reused, problems caused by the remaining printed layer 111 (fisheyes, unnecessary coloring, etc.) do not occur.

[0063] In the example shown, when removing the printed layer 111, the heat-shrinkable film 101, including at least the non-sealed area 121b, is simply immersed in an alkaline solution. However, in order to reliably remove the printed layer 111, it is preferable to agitate the film while it is immersed in the alkaline solution, rather than simply immersing it in the alkaline solution.

[0064] Incidentally, allowing the non-sealed region 121b of the seamed portion 121 to function as a flow path for the alkaline solution is particularly effective when the non-sealed portion 122 has inner residue 101f. This is because the presence of inner residue 101f narrows the space in the non-sealed portion 122 toward the sealed region 121a on the inner end 102 side, making it difficult for the alkaline solution to sufficiently penetrate this space from the inner end 102 side. Even in such a case, allowing the non-sealed region 121b of the seamed portion 121 to function as a flow path for the alkaline solution allows the alkaline solution to flow from the non-sealed region 121b toward the inner end 102, thereby sufficiently flowing the alkaline solution toward the inner end 102 side of the non-sealed portion 122, thereby ensuring the removal of the printed layer 111. Conversely, allowing the alkaline solution to flow from the inner end 102 toward the non-sealed region 121b also allows the alkaline solution to flow sufficiently toward the inner end 102 side of the non-sealed portion 122, thereby ensuring the removal of the printed layer 111. Naturally, even if there is no non-seaming portion 122, that is, no inner residue 101f, the printing layer 111 can be sufficiently removed.

[0065] The anvil pattern, which indicates the shape and formation pattern of the sealed regions 121a in the above-described seaming portion 121, is a pattern in which substantially circular sealed regions 121a are formed at predetermined intervals along the circumferential direction. In other words, the anvil pattern in the seaming portion 121 is a pattern in which the sealed regions 121a and the non-sealed regions 121b are alternately arranged along the circumferential direction. However, the anvil pattern is not limited to the example of the seaming portion 121, and the anvil patterns shown in the following modified examples 1 and 2 also achieve the same effect as the seaming portion 121. In other words, even in the anvil patterns shown in modified examples 1 and 2, the non-sealed regions function as flow paths for fluids (gas, liquid).

[0066] <Variation 1> Fig. 11 is a diagram showing an anvil pattern in the seaming portion 130. As shown in Fig. 11, the seaming portion 130 is formed with a plurality of sealed regions 130a, each of which is formed in a linear shape extending in a direction intersecting the circumferential direction. In the spaces between adjacent sealed regions 130a, non-sealed regions 130b are formed in a linear shape extending in a direction intersecting the circumferential direction.

[0067] The sealed regions 130a and non-sealed regions 130b in the seaming portion 130 are arranged alternately in the circumferential direction, similar to the sealed regions 121a and non-sealed regions 121b in the seaming portion 121. In other words, it is preferable that the non-sealed regions 130b in the seaming portion 130 do not coincide with either of the shrinkage directions (circumferential direction or axial direction) of the heat-shrinkable film 101. To achieve this, a sealed region that breaks the continuity of the non-sealed regions 130b in the shrinkage direction needs to be present in the shrinkage direction of the heat-shrinkable film 101.

[0068] Here, the direction in which heat-shrinkable film 101 mainly shrinks is the circumferential direction, so sealed regions 130a and non-sealed regions 130b are arranged alternately along the circumferential direction indicated by the arrows in Fig. 11. Therefore, in seaming portion 130 as well, non-sealed regions 130b have a shape that does not extend in the direction that coincides with the direction in which heat-shrinkable film 101 mainly shrinks (the circumferential direction), as in seaming portion 121.

[0069] 11 shows an example in which the width of the sealed region 130a is narrower than the width of the non-sealed region 130b, but this is not limiting. As long as the sealing function of the seaming region 130 is sufficient, the width of the sealed region 130a may be wider than the width of the non-sealed region 130b, or the width of the sealed region 130a may be the same as the width of the non-sealed region 130b.

[0070] Furthermore, as long as the sealing function is sufficient, the intervals between adjacent sealing regions 130a may or may not be equal.

[0071] Furthermore, the number of sealing regions 130a formed is not particularly limited as long as the sealing function in the seaming portion 130 is sufficient. The direction in which the sealing regions 130a are formed is not particularly limited as long as it intersects the circumferential direction. The intersecting angle may be steep or gentle, and may be any angle other than an angle parallel to the circumferential direction (0°) or an angle perpendicular to the circumferential direction (90°).

[0072] Furthermore, adjacent sealed regions 130a do not have to be parallel to each other. That is, the directions in which the sealed regions 130a are formed may differ. In this case, taking into consideration the escape of liquid (liquid for removing the printed layer) in the non-sealed region 130b of the seaming portion 130, it is preferable that adjacent sealed regions 130a are formed so as not to intersect at both circumferential edges of the seaming portion 130.

[0073] <Variation 2> FIG. 12 is a diagram showing an anvil pattern in the seaming section 140. As shown in FIG. 12, the seaming section 140 includes a plurality of first seal regions 140a and a plurality of second seal regions 140b, each of which is formed as a strip extending in a direction perpendicular to the circumferential direction. The first seal region 140a and the second seal region 140b are adjacent to each other in the circumferential direction, and the positions of both ends of the first seal region 140a in the direction perpendicular to the circumferential direction are different in the direction perpendicular to the circumferential direction from the positions of both ends of the second seal region 140b adjacent to the first seal region 140a in the direction perpendicular to the circumferential direction. Note that the first end 101a of the heat-shrinkable film 101 in the seaming section 140 is preferably sealed intermittently. This is to prevent the first end 101a from rising up after shrinkage. 12, the second sealing regions 140b are formed intermittently at positions (on the right side in FIG. 12) corresponding to the first end 101a of the heat-shrinkable film 101 in the seaming portion 140. If the arrangement of the first sealing regions 140a and the second sealing regions 140b were reversed from that in FIG. 12, the first sealing regions 140a would be formed intermittently at positions corresponding to the first end 101a of the heat-shrinkable film 101 in the seaming portion 140.

[0074] The first sealed region 140a, the second sealed region 140b, and the non-sealed region 140c in the seaming region 140 are arranged alternately in the circumferential direction, similar to the sealed region 121a and the non-sealed region 121b in the seaming region 121. In other words, it is preferable that the non-sealed region 140c in the seaming region 140 does not coincide with any of the shrinkage directions (circumferential direction or axial direction) of the heat-shrinkable film 101. To achieve this, a sealed region that breaks the continuity of the non-sealed region 140c in the shrinkage direction needs to be present in the shrinkage direction of the heat-shrinkable film 101.

[0075] Here, since the heat-shrinkable film 101 mainly shrinks in the circumferential direction, the first sealed region 140a and the non-sealed region 140c, and the second sealed region 140b and the non-sealed region 140c are alternately arranged along the circumferential direction indicated by the arrows in Fig. 12. Therefore, in the seaming portion 140 as well, similarly to the seaming portion 121, the non-sealed region 140c has a shape that does not extend in the direction that coincides with the main shrinkage direction (circumferential direction) of the heat-shrinkable film 101.

[0076] In the seaming portion 140 shown in FIG. 12, the first sealing region 140a and the second sealing region 140b have substantially the same shape, but this is not limited thereto. For example, the width of the first sealing region 140a may be wider or narrower than the width of the second sealing region 140b. The length of the first sealing region 140a may be longer or shorter than the length of the second sealing region 140b. Furthermore, the sizes of the first sealing regions 140a and the second sealing regions 140b do not need to be the same. The widths and lengths of the first sealing region 140a and the second sealing region 140b may be any width and length as long as they adequately function as a seal in the seaming portion 140. While the width of the first sealing region 140a and the second sealing region 140b are both formed in a direction perpendicular to the circumferential direction indicated by the arrows in FIG. 12, this is not limited thereto and they may be formed at a predetermined angle other than a parallel angle to the circumferential direction.

[0077] Furthermore, the number of first seal regions 140a and second seal regions 140b formed is not particularly limited as long as the function of sealing in the seaming portion 140 is sufficient.

[0078] In the case of a cylindrical label, the sealing of the seam of the overlapping portion is not limited to the ultrasonic sealing described above, and other methods may be used. In short, it is sufficient that the seam is sealed so as to include an unsealed area that forms a space that allows communication from the inside of the cylindrical label to the outside.

[0079] For example, if the liquid used to remove the printed layer is an alkaline solution, an alkali-soluble resin is partially printed in the area of ​​the heat-shrinkable film that will become the seam area, and then the heavy seam area is center-sealed with a solvent. The printing pattern of the alkali-soluble resin in this case can be the same as the non-sealed area formation pattern in the seam area described above, as shown in Figures 5, 11, and 12. After the alkali-soluble resin dissolves in the alkali-soluble resin, the printed area can function as a fluid flow path connecting the inside and outside of the cylindrical label. Therefore, even if the alkali-soluble resin is partially printed in the area of ​​the heat-shrinkable film that will become the seam area, a flow path for the alkali-soluble resin to remove the printed layer can be formed, similar to the non-sealed area described above. As a result, the area of ​​the seam where the alkali-soluble resin is printed functions as a fluid flow path, similar to the non-sealed area 121b shown in Figure 4. Therefore, when reusing the cylindrical label, the printed layer near the inner residue of the non-seamed area can be reliably removed by simply immersing the recovered heat-shrinkable film together with the seam area in a liquid for removing the printed layer. The resin printed on the area of ​​the heat-shrinkable film that is to become the seam portion is a resin that is removed by the liquid used to remove the printed layer, so it may be selected to match the printed layer.

[0080] 10, the printing layer of the tubular label 1A peeled from the container 301 of the label molded body 3 has been described. However, the printing layer may be removed while the tubular label 1A is attached to the container 301 of the label molded body 3. In this case, the label molded body 3 with the tubular label 1A attached to the container 301 may be immersed in a container filled with alkaline solution so that at least the tubular label 1A is immersed in the alkaline solution, thereby removing the printing layer of the tubular label 1A. In this case, the non-sealed region 121b in the seaming portion 121 of the tubular label 1A also functions as a flow path for the alkaline solution, ensuring sufficient removal of the printing layer. The tubular label 1A from which the printing layer has been removed is peeled from the container 301 and reused.

[0081] The present invention is not limited to the above-described embodiments, 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 the present invention. [Explanation of symbols]

[0082] 1 Raw material, 1A Cylindrical label, 3 Label formed body, 101 Heat shrinkable film, 101a First end, 101b Second end, 101c First opposing surface, 101d Second opposing surface, 101e Inner peripheral surface, 101f Inner residue, 102 Inner end, 103 Outer end, 111 Printed layer, 120 Overlapping portion, 121 Seaming portion, 121a Sealed area, 121b Non-sealed area, 122 Non-sealed portion, 130 Seaming portion, 130a Sealed area, 130b Non-sealed area, 140 Seaming portion, 140a First sealing area, 140b Second sealing area, 140c Non-sealed area, 201 Sealing device, 210 Ultrasonic oscillator, 240 Anvil portion, 240a Surface, 241 Protrusion, 301 Container, 301a film attachment surface

Claims

1. A cylindrical label formed by overlapping ends of a heat-shrinkable film and joining the ends at a seam to form a cylindrical shape, a liquid-removable printed layer is formed on the surface of the heat-shrinkable film inside the cylindrical label; The seaming portion is a non-sealed region where the heat-shrinkable films are not sealed together and where a liquid for removing the printed layer is poured, and a sealed region where the heat-shrinkable films are sealed together, The non-sealed area communicates from the inside of the cylindrical label to the outside of the cylindrical label.

2. the overlapped portion of the heat-shrinkable film includes the seaming portion and a non-seaming portion formed adjacent to the seaming portion and in which the heat-shrinkable films face each other in an unsealed state; The cylindrical label according to claim 1 , wherein the printed layer is formed on at least one of the opposing surfaces of the heat-shrinkable films in the non-seamed portion.

3. the printed layer is an alkali-soluble printed layer, The cylindrical label according to claim 1 or 2, wherein the liquid is an alkaline aqueous solution.

4. A method for removing a printed layer formed in a cylindrical label by overlapping ends of a heat-shrinkable film and joining the ends at a seaming portion, the method comprising removing a printed layer formed in the cylindrical label and removable with a liquid, the method comprising: the seaming portion includes a non-sealed region where the heat-shrinkable films are not sealed together and a sealed region where the heat-shrinkable films are sealed together, and the non-sealed region communicates from the inside to the outside of the cylindrical label; A method for removing a printed layer, comprising the step of immersing the heat-shrinkable film including at least the non-sealed region in a liquid for removing the printed layer to remove the printed layer.

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