JP2025099253A - Heat shrinkable film and packaging container - Google Patents

Abstract

To provide a heat shrinkable film allowing easy removal from a container when attached as a cylindrical label to the container.SOLUTION: A heat shrinkable film is to be attached as a cylindrical label to a container. The heat shrinkable film includes a film main body having a perforation. The perforation extends so as to allow a removal of the cylindrical label by breaking the cylindrical label along the perforation when the heat shrinkable film is attached onto the container as the cylindrical label. In a target portion of the film main body, a detachability improvement layer is laminated in a vicinity of the perforation. The target portion is a portion to be an edge part in an axial direction of the cylindrical label when removing the cylindrical label.SELECTED DRAWING: Figure 2

Description

The present invention relates to a heat-shrinkable film and a packaging container.

Conventionally, a heat-shrinkable film molded into a cylindrical shape has been attached as a label to the body or cap of a container. Such heat-shrinkable labels are sometimes formed with perforations to make them easier to peel off (e.g., Patent Documents 1 and 2).

JP 2010-002458 A JP 2017-124864 A

A heat-shrinkable label attached to a container adheres strongly to the container, and usually there is almost no gap between the label and the container. Therefore, even if perforations are formed, it is not necessarily easy to peel the label off the container. This is because it is difficult to insert fingertips or nails into the gap between the container and the label, making it difficult to start peeling the label along the perforations. In this regard, in Patent Document 1, in addition to the perforations, a notch is made at the end of the label. In Patent Document 2, in addition to the perforations, a tab portion is provided at the end of the label. However, from the viewpoint of peelability, or from the viewpoint of other aspects such as design and productivity, the conventional methods are not necessarily sufficient. Therefore, a new method is required for providing a heat-shrinkable label with high peelability.

The object of the present invention is to provide a heat-shrinkable film that can be easily peeled off from a container when attached to the container as a cylindrical label, and a packaging container wrapped in the heat-shrinkable film.

Item 1. A heat-shrinkable film that is attached to a container as a cylindrical label,
A film body having perforations formed therein;
the perforations extend such that, when the heat-shrinkable film is attached to the container as the tubular label, the tubular label can be peeled off from the container by tearing the tubular label along the perforations;
A peelability improving layer is laminated in the vicinity of the perforation in the target portion of the film body,
The target portion is a portion that becomes an axial end portion of the cylindrical label when the cylindrical label is peeled off.
Heat shrinkable film.

Item 2. The release property improving layer is a printing layer or a coating layer.
Item 1. A heat-shrinkable film.

Item 3. The peelability improving layer is intermittently laminated along the entire circumference of the target portion in the target portion.
Item 3. The heat-shrinkable film according to item 1 or 2.

Item 4. The peelability improving layer is laminated so as to overlap the perforation in the target portion.
Item 4. The heat-shrinkable film according to any one of items 1 to 3.

Item 5. A cylindrical label formed from the heat-shrinkable film according to any one of items 1 to 4,
A packaging container comprising: a container to which the tubular label is attached.

The present invention provides a heat-shrinkable film that can be easily peeled off from a container when attached to the container as a cylindrical label.

FIG. 2 is a side view of a packaging container according to one embodiment. FIG. 2 is a side view of the packaging container of FIG. 1 viewed from a different angle. FIG. 2 is a plan view of the packaging container of FIG. 1 . FIG. 2 is a development view of a heat shrink film according to an embodiment. Cross-sectional view taken along line B1-B1 in Figure 4. Cross-sectional view taken along line B2-B2 in Figure 4. FIG. 2 is a diagram showing a flow of a method for manufacturing a heat-shrinkable film and a packaging container according to an embodiment. FIG. 11 is a side view of a packaging container according to a modified example.

The following describes a heat-shrinkable film and packaging container according to one embodiment of the present invention, with reference to the drawings.

<1. Overall structure of packaging container>
1 and 2 show two side views of the packaging container 1 according to the present embodiment seen from different angles, and FIG. 3 shows a plan view of the packaging container 1. FIG. 1 is a side view seen from the direction of the arrow A1 shown in FIG. 3, and FIG. 2 is a side view seen from the direction of the arrow A2 shown in FIG. 3. The packaging container 1 includes a container 2 and a tubular label L attached to the container 2. The tubular label L is a shrink label and is formed from a heat-shrinkable film 3. FIG. 4 shows a development view of the heat-shrinkable film 3 before being processed into the tubular label L. In the description of the present embodiment, unless otherwise specified, the top and bottom (vertical direction) and the left and right (horizontal direction) are defined as shown in FIG. 4. The heat-shrinkable film 3 is flat in the state shown in FIG. 4, and is formed into a tubular shape by overlapping its left end and right end to form the tubular label L. Then, the container 2 is placed inside the tubular label L so that the tubular label L surrounds the container 2, and heat is applied to the tubular label L in this state. As a result, the cylindrical label L shrinks and deforms to fit the outer shape of the container 2, and comes into close contact with the outer surface of the container 2. In this manner, the heat-shrinkable film 3 is attached to the container 2 as the cylindrical label L.

The container 2 according to this embodiment has a main body 20 and a cap 25. The main body 20 has a bottom 21, a body 22, and a cap attachment part 23. The parts 20, 22, 23, and 25 are covered by a cylindrical label L and cannot be seen from the outside at least partially. However, for convenience of explanation, the positions of the parts hidden by the cylindrical label L are indicated by reference numerals 20, 22, 23, and 25 in Figs. 1 to 3. The bottom 21 according to this embodiment is circular in plan view. The body 22 stands from the outer periphery of the bottom 21 and is generally cylindrical, although the diameter of the cross section varies along the vertical direction. The cap attachment part 23 is provided on the upper part of the body 22. The cap 25 is attached to the cap attachment part 23. The cap 25 according to this embodiment is circular in plan view. The cap 25 may be configured to be freely opened and closed. In this case, a screw type, a hinge type, or the like may be considered. The cap 25 may be configured so that once opened it cannot be re-closed.

The material of the main body 20 is not particularly limited, but the main body 20 according to this embodiment is made of resin, and as a preferred example, it can be made of polyester-based resin such as polyethylene terephthalate (PET) or polyolefin-based resin. As other examples, the main body 20 can be made of glass, paper, etc. The material of the cap 25 is also not particularly limited, but the cap 25 according to this embodiment is made of resin, and as a preferred example, it can be made of polyolefin-based resin or polyester-based resin. In addition, although not limited thereto, in this embodiment, the main body 20 is configured to be transparent or translucent (hereinafter, sometimes referred to as clear) so that the contents of the container 2 can be seen, and the cap 25 is configured to be opaque.

The cylindrical label L according to this embodiment is attached so as to cover the body 22, the cap attachment portion 23, and the cap 25. As shown in Figs. 1 and 2, the body 22 is covered by the cylindrical label L except for its lower portion. The cap attachment portion 23 is also covered by the cylindrical label L. The bottom surface portion 21 is not covered by the cylindrical label L. As shown in Fig. 3, the cap 25 is covered by the cylindrical label L at its side portion 25S and the outer periphery of its top surface portion 25T, but the center of the top surface portion 25T is not covered.

As described above, the heat shrinkable film 3 according to this embodiment does not cover the entire outer surface of the clear main body 20 when attached to the container 2, and the bottom 21 and the lower part of the barrel 22 are exposed. Therefore, the heat shrinkable film 3 according to this embodiment is not a so-called light-blocking film, and the contents can be seen through the exposed parts of the clear main body 20. As will be described in detail later, the heat shrinkable film 3 according to this embodiment has a clear part formed therein, and the contents can be seen through this part as well.

The use of container 2 is not particularly limited, but a preferred example is a container for food such as dressing, soy sauce, or noodle soup, or a beverage container.

2. Heat-shrinkable film
Next, the heat shrinkable film 3 will be described in detail. Fig. 5A is a cross-sectional view taken along line B1-B1 in Fig. 4, and Fig. 5B is a cross-sectional view taken along line B2-B2 in Fig. 4. As shown in Figs. 4, 5A, and 5B, the heat shrinkable film 3 includes a film body 4 and a printed layer 5 laminated on the film body 4. In the drawings, the printed layer 5 is shown in dark gray, and the portion of the film body 4 on which the printed layer 5 is not laminated is shown in light gray.

In this embodiment, the film body 4 is configured to be clear, and the printing layer 5 is configured to be opaque. The printing layer 5 constitutes a decorative surface on which a pattern is applied to decorate the container 2 when the heat-shrinkable film 3 wraps the container 2. The pattern applied to the decorative surface may include characters that explain various information related to the contents of the container 2. The film body 4 may also be configured to be opaque.

The material of the film body 4 is not particularly limited as long as it has heat shrinkability. As a preferred example, the film body 4 can be formed from a polyester resin, a polystyrene resin (including hybrid polystyrene), a polyolefin resin, or a mixture or laminate of these.

The material of the printed layer 5 is not particularly limited, and the printed layer 5 can be formed using various inks suitable for laminating to the film body 4. The material of the printed layer 5 is typically a colored (opaque) ink, but clear ink can also be used at least partially. In the latter case, clear ink can be used for part or all of the printed layer 5, so that part or all of the printed layer 5 is clear rather than opaque.

Of the two sides of the film body 4, the side that faces the container 2 (inside) when the heat-shrinkable film 3 is used to package the container 2 is called the back side, and the side that faces the outside is called the front side. The printed layer 5 may be formed on either the back side or the front side of the film body 4, or on both sides. However, if the film body 4 is a clear film, it is preferable to form the printed layer 5 on the back side from the standpoint of appearance. The printed layer 5 in this embodiment is disposed on the back side of the film body 4. Note that FIG. 4 is a view of the heat-shrinkable film 3 as viewed from the front side, and the printed layer 5 on the back side can be seen through the clear film body 4.

In this embodiment, the film body 4 included in the heat-shrinkable film 3 is formed with perforations L1 to L8. In the example of FIG. 5A and FIG. 5B, the perforations L1 to L6 penetrate the film body 4 and the printing layer 5. The same is true for the perforations L7 and L8. The perforations L1 to L8 are formed to make it easier to break the tubular label L attached to the container 2 and to peel the tubular label L from the container 2. Therefore, the perforations L1 to L8 extend to a position in the heat-shrinkable film 3 where the break is expected when the tubular label L is peeled off from the container 2. As a result, when the heat-shrinkable film 3 is attached to the container 2 as the tubular label L, the tubular label L can be easily peeled off from the container 2 by breaking the tubular label L along the perforations L1 to L8.

The perforations L1 to L4 are for peeling off the upper film portion 31 of the cylindrical label L, which mainly covers the cap 25, from the container 2 when the packaging container 1 is opened. The heat-shrinkable film 3 is separated into the upper film portion 31 and the lower film portion 32 at the boundaries of the perforations L3 and L4. The perforations L3 and L4 extend laterally (left-right) from the left edge to the right edge of the heat-shrinkable film 3. The perforations L3 and L4 run side by side in the horizontal direction with a small distance between them in the vertical direction. The perforations L1 and L2 extend from the upper edge of the heat-shrinkable film 3 to the perforation L3. The perforation L3 is located above the perforation L4. The perforations L1 and L2 in this embodiment extend from the upper edge of the heat-shrinkable film 3 toward the perforation L3 so that the distance gradually decreases. A tear-away portion 31A is formed in the upper portion of the film 31 and is surrounded by perforations L1 to L3.

A method of opening the packaging container 1 will be described. First, the user hooks a fingernail or a fingertip on the portion of the cylindrical label L surrounded by the circle C1 in Figs. 1 and 3, and pulls the above-mentioned opening portion 31A downward. The portion surrounded by the circle C1 is the portion near the perforations L1 and L2 of the portion of the film upper portion 31 that covers the outer periphery of the top surface portion 25T of the cap 25. This causes the film upper portion 31 to break along the perforations L1 and L2. Next, by pulling the opening portion 31A horizontally along the perforations L3 and L4, the portion between the opening portion 31A and the film lower portion 32 is broken along the perforations L3 and L4, and the opening portion 31A is separated from the film lower portion 32. This causes the opening portion 31A to be peeled off and removed from the container 2. Next, the portion of the upper film 31 other than the removed opening portion 31A (hereinafter referred to as the remaining portion) 31B is picked up and pulled horizontally along the perforations L3 and L4. This causes a break between the remaining portion 31B and the lower film 32 along the perforations L3 and L4, and the remaining portion 31B is separated from the lower film 32. As a result, the remaining portion 31B is peeled off and removed from the container 2. Note that the remaining portion 31B may be removed before the opening portion 31A. As a result, the entire upper film 31 is removed from the packaging container 1, exposing the cap 25. The user opens the cap 25 in this state.

As a result, the container 2 is in a state where only the lower film portion 32 of the cylindrical label L is attached. Although not limited to this, a typical method of use is for the container 2 to be used with only the lower film portion 32 attached until the contents are used up (until removal of the contents is complete). During this time, the contents can be removed little by little from the main body portion 20 or the contents remaining in the main body portion 20 can be preserved by opening and closing the removal opening of the container 2 with the cap 25.

After the contents are used up, the container 2 is discarded. When discarded, the lower film portion 32 attached to the container 2 is also peeled off and removed from the container 2, typically for recycling purposes. The perforations L5 and L6 are mainly for peeling off the lower film portion 32 covering the main body portion 20 of the container 2 from the container 2. In the example of FIG. 2 and FIG. 4, the perforations L5 and L6 extend in the vertical direction from the lower edge to the upper edge of the heat-shrinkable film 3. The perforation L5 is formed near the left end of the heat-shrinkable film 3 in the expanded state, and the perforation L6 is formed near the right end of the heat-shrinkable film 3 in the expanded state. As a result, in the cylindrical label L formed by overlapping the left end and the right end of the heat-shrinkable film 3, the perforations L5 and L6 run parallel to each other in the vertical direction with a small distance between them in the horizontal direction (see FIG. 2). In FIG. 2 and FIG. 3, the overlapped portion O1 of the heat-shrinkable film 3 is indicated by hatching with oblique lines.

Next, a method for peeling the lower film portion 32 of the tubular label L from the container 2 will be described. There are typically two methods. In the first method, the user hooks a fingernail or a fingertip on the portion of the tubular label L surrounded by circle C2 in FIG. 2 and pulls that portion upward from the lower edge to the upper edge of the lower film portion 32. The portion surrounded by circle C2 is the portion near perforations L5 and L6 at the lower end of the lower film portion 32. This causes the lower film portion 32 to break along perforations L5 and L6, and the lower film portion 32 is peeled off and removed from the container 2.

In the second method, the user hooks a fingernail or a fingertip on the portion of the cylindrical label L that is surrounded by circle C3 in FIG. 2 and pulls that portion downward from the upper edge to the lower edge of the lower film 32. The portion surrounded by circle C3 is the portion near the perforations L5 and L6 at the upper end of the lower film 32. This causes the lower film 32 to break along the perforations L5 and L6, and the lower film 32 is peeled off and removed from the container 2.

The perforations L7 and L8 are perforations to assist in breaking the tubular label L along the perforations L5 and L6. The perforations L7 are formed so as to run parallel to the perforations L5 in the vicinity of the perforations L5. The perforations L8 are formed so as to run parallel to the perforations L6 in the vicinity of the perforations L6. In the example of FIG. 2 and FIG. 4, the perforations L7 and L8 extend slightly upward from the lower edge of the heat shrinkable film 3 and do not reach the upper edge of the heat shrinkable film 3 or the upper edge of the lower film portion 32. However, one or both of the perforations L7 and L8 may reach the upper edge of the heat shrinkable film 3 or the upper edge of the lower film portion 32. One or both of the perforations L7 and L8 may also be omitted.

2 and 4, the perforations L5 and L6 are also formed in the upper film 31. Therefore, the perforations L5 and L6 also function as perforations for peeling the upper film 31 from the container 2 when opening the packaging container 1. In this case, the user hooks a fingernail or a fingertip on the part of the cylindrical label L surrounded by the circle C4 in FIG. 2 and FIG. 3, and pulls the part downward from the upper edge to the lower edge of the upper film 31. The part surrounded by the circle C4 is the part of the upper film 31 that covers the outer periphery of the top surface 25T of the cap 25 and is near the perforations L5 and L6. This causes the upper film 31 to break along the perforations L5 and L6. Next, the upper film 31 is picked up and pulled horizontally along the perforations L3 and L4. This separates the upper film 31 from the lower film 32 along the perforations L3 and L4, and the upper film 31 is peeled off and removed from the container 2. The user then opens the exposed cap 25.

As described above, the portions surrounded by the circles C1 to C4 shown in Figures 1 to 4 can be the starting points for breaking the cylindrical label L. Therefore, hereinafter, these portions will be referred to as the breaking starting points C1 to C4.

<3. Peelability improving layer>
In the above manner, the tubular label L can be peeled off from the container 2. The tubular label L is provided with peelability improving layers D1 to D7 for improving the peelability of the tubular label L. In this embodiment, parts of the printed layer 5 laminated on the film body 4 constitute the peelability improving layers D1 to D7.

As shown in FIG. 4, the printing layer 5 includes an upper portion 5U and a lower portion 5D. In this embodiment, the upper portion 5U and the lower portion 5D are both rectangular on the film body 4. The upper edge of the upper portion 5U extends laterally from the upper edge of the film body 4 with a slight gap therebelow. The lower edge of the upper portion 5U extends laterally from the perforation L4 with a slight gap therebelow. The left and right edges of the upper portion 5U extend vertically from the left and right edges of the film body 4 with a slight gap therebetween. The upper edge of the lower portion 5D extends horizontally from the lower edge of the upper portion 5U with a slight gap therebelow. The lower edge of the lower portion 5D extends horizontally from the lower edge of the film body 4 with a slight gap therebelow. The left and right edges of the lower portion 5D extend vertically from the left and right edges of the film body 4 with a slight gap therebetween.

The film body 4 includes an upper end 4U, a middle portion 4M, a lower end 4D, a left end 4L, and a right end 4R, where the upper and lower portions 5U and 5D of the printed layer 5 are not laminated. However, the printed layer 5 is partially laminated on the upper end 4U and the lower end 4D as peelability improving layers D1 to D5 and a layer of region D8 described below.

Hereinafter, the portion of the film body 4 that will become the axial end of the tubular label L when peeling the tubular label L from the container 2 is referred to as the target portion. As shown in FIG. 4, the film body 4 according to this embodiment includes three target portions T1 to T3. The target portions T1 to T3 included in the tubular label L are each formed in a ring shape. In this example, the target portion T1 coincides with the upper end 4U of the film body 4, and the target portion T2 coincides with the lower end 4D of the film body 4. The target portion T3 is included in the lower film portion 32 and is a portion that is along the perforation L4 at a position below the perforation L4. In other words, the target portion T3 is the portion that will become the axial end (upper end) of the lower film portion 32 (tubular label L) when the lower film portion 32 is to be further peeled off after the upper film portion 31 is peeled off from the container 2 along the perforations L3 and L4.

The peelability improving layers D1 to D7 are laminated in the vicinity of the perforations L1 to L8 in the target portions T1 to T3. More specifically, in the target portion T1, the peelability improving layer D1 is laminated in the vicinity of the perforations L1 and L2, the peelability improving layer D4 is laminated in the vicinity of the perforation L5, and the peelability improving layer D5 is laminated in the vicinity of the perforation L6. In the target portion T1, the printed layer 5 is not present in the portion where the peelability improving layers D1, D4, and D5 are not laminated. Therefore, the printed layer 5 including the peelability improving layers D1, D4, and D5 is laminated in the target portion T1 intermittently along the entire circumference (entire width) of the target portion T1.

In the target portion T2, the peelability improving layer D2 is laminated near the perforations L5 and L7, and the peelability improving layer D3 is laminated near the perforations L6 and L8. In the target portion T2, the printed layer 5 is laminated at the position of the region D8. The region D8 occupies the same position in the lateral direction as the peelability improving layer D1. In the target portion T2, there is no printed layer 5 other than the layer of the region D8 and the peelability improving layers D2 and D3. Therefore, the printed layer 5 including the layer of the region D8 and the peelability improving layers D2 and D3 is laminated intermittently in the target portion T2 along the entire circumference (entire width) of the target portion T2.

In the target portion T3, the peelability improving layer D6 is laminated near the perforation L5, and the peelability improving layer D7 is laminated near the perforation L6. The peelability improving layers D6 and D7 are included in the upper portion 5U of the printed layer 5. Therefore, in the target portion T3, the printed layer 5 is present even in the portions where the peelability improving layers D6 and D7 are not laminated, except for the positions of the left end 4L and the right end 4R. In the target portion T2, the printed layer 5 including the peelability improving layers D6 and D7 is laminated continuously along substantially the entire circumference (entire width) of the target portion T3.

When the heat shrinkable film 3 is formed into the cylindrical label L, the peelability improving layer D1 constitutes the breakage initiation point C1 in FIG. 1 and FIG. 3. The peelability improving layers D2 and D3 are superimposed on each other to constitute the breakage initiation point C2 in FIG. 2. The peelability improving layers D4 and D5 are superimposed on each other to constitute the breakage initiation point C4 in FIG. 2 and FIG. 3. The peelability improving layers D6 and D7 are superimposed on each other to constitute the breakage initiation point C3 in FIG. 2.

In the heat-shrinkable film 3, the portion where the printed layer 5 is laminated is thicker than the other portions. Therefore, when the tubular label L is heat-shrunk and attached to the container 2 so as to be in close contact with the container 2, the portion where the peelability improving layers D1 to D7 are laminated (breakage start points C1 to C4) is slightly raised from the container 2. In particular, the breakage start points C1, C2, and C4 located at the end of the tubular label L during heat shrinkage may be warped relative to the container 2. This is because the breakage start points C1 to C4 are thicker and harder than the portion where the printed layer 5 is not laminated, and heat shrinkage is suppressed. Also, as described above, the peelability improving layers D1 to D7 are located at positions that become the end of the tubular label L when the tubular label L is peeled off. Therefore, when the tubular label L is peeled off, it is easy to catch a nail or a fingertip in the small gap between the portion where the peelability improving layers D1 to D7 are present (breakage start points C1 to C4) and the container 2. Then, by picking up the part that is hooked with a fingernail or a fingertip (breaking start points C1 to C4) and pulling it, the cylindrical label L can be easily torn.

For comparison, consider the case where the cylindrical label L is torn starting from a portion of the target portions T1 to T3 where the printing layer 5 is not laminated (for example, the portion surrounded by the circle E in Figures 2 and 4; hereinafter, referred to as portion E). When the cylindrical label L is thermally shrunk to be attached to the container 2, such portion E curls and collapses toward the container 2, adhering more firmly to the container 2. This is because portion E is thinner and softer than the portion where the printing layer 5 is laminated, and is more susceptible to thermal shrinkage. Therefore, it is not possible to properly insert a fingernail or fingertip between portion E and the container 2, and it is not possible to properly pick up portion E. If you try to pick it up by force, portion E will turn up and you may no longer be able to pick it up. In particular, if portion E is in contact with an uneven portion of the container 2, such as an inclined or curved portion in a side view, it may be difficult to pick up portion E. The same problem may also occur in the case of a container 2 with high strength. Therefore, even if the perforations were formed so as to overlap with part E, it may be difficult to tear the cylindrical label L with part E as the tearing initiation point.

In this embodiment, the peelability improving layers D1 to D7 are laminated so as to overlap the perforations L1 to L8 in the target portions T1 to T3. However, at least one of the peelability improving layers D1 to D7 may be positioned slightly away from the perforations L1 to L8 without overlapping them. In this case, it is preferable that the peelability improving layers D1 to D7 are positioned within a distance of 0.001 mm to 1.0 mm from the perforations L1 to L8.

In this embodiment, the peelability improving layers D1 to D7 are disposed between the pair of perforations in the cylindrical label L. However, at least one of the peelability improving layers D1 to D7 may not be disposed between the pair of perforations, but may be disposed outside the pair of perforations. At least one of the peelability improving layers D1 to D7 may overlap only one of the pair of perforations. The peelability improving layer may be disposed over the entire area or almost the entire area of the target portion, slightly away from the perforations. In this case, the portion where the peelability improving layer is laminated becomes floating during heat shrinkage, and the portion where the peelability improving layer is not laminated also floats, and as a result, a break initiation point may be formed near the perforations.

From the viewpoint of improving the function of the fracture initiation points C1 to C4, the length in the fracture direction of the peelability improving layers D1 to D7 is preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 2.0 mm or more, and even more preferably 3.0 mm or more.

From the viewpoint of hardness (and thus of improving the function of the fracture initiation points C1 to C4), the thickness (average) of the peelability improving layers D1 to D7 is preferably 0.5 μm or more, more preferably 2.0 μm or more, and even more preferably 5 μm or more. The thickness (average) of the peelability improving layers D1 to D7 is preferably 10 μm or less. The thickness (average) of the peelability improving layers D1 to D7 can be measured by a method conforming to JIS K7130. The ratio of the thickness (average) of the peelability improving layers D1 to D7 to the thickness (average) of the film body 4 is preferably 2% or more, more preferably 5% or more, and even more preferably 10% or more. The ratio is preferably 40% or less, more preferably 30% or less, and even more preferably 25% or less. The thickness (average) of the film body 4 can also be measured by a method conforming to JIS K7130. The values stated here also apply to the entire printing layer 5, including the peelability improving layers D1 to D7.

It is preferable to use the same ink as that used for the other parts of the printed layer 5 as the ink constituting the peelability improving layers D1 to D7. When multiple color inks are used for the other parts of the printed layer 5, it is preferable to use the same ink as one or more of the colors. In this case, it is possible to form the peelability improving layers D1 to D7 simultaneously with the other parts of the printed layer 5, and costs can be reduced. In addition, from the viewpoint of hardness (and thus from the viewpoint of improving the function of the fracture initiation points C1 to C4), it is preferable to use a colored (opaque) ink, for example, a white ink, as the material for the peelability improving layers D1 to D7, but a clear ink may also be used. It is not necessary to use the same ink for all of the peelability improving layers D1 to D7, and different inks may be used for each.

A coating agent may be applied to at least one of the printed layer 5, between the film body 4 and the printed layer 5, and on the surface of the film body 4 opposite the printed layer 5 to form a coating layer. Alternatively or in addition to this, an additive may be added to the ink that constitutes the printed layer 5. The proportion of the additive is preferably about 3 to 12 wt % of the total ink. The coating agent and additive may include one or more of a hardener, an antiblocking agent, a surface protective agent, and an ultraviolet protection agent. In addition, a release layer for deinking may be formed between the film body 4 and the printed layer 5 as a coating layer.

When the above-mentioned coating agent and/or additive is used (particularly when a curing agent is used), the thermal contraction of the fracture starting points C1 to C4 can be further suppressed, and the function of the fracture starting points C1 to C4 can be further improved. Therefore, the above-mentioned coating layer can constitute the peelability improving layers D1 to D7 together with the printing layer 5 at the positions of the fracture starting points C1 to C4. When focusing on the function of the fracture starting points C1 to C4, the coating layer may be formed only on the parts of the entire printing layer 5 that constitute the peelability improving layers D1 to D7. Similarly, the additive may be added only to the ink that constitutes the peelability improving layers D1 to D7.

The printing layer 5 may be a single layer or a multilayer. The coating layer may also be a single layer or a multilayer.

The ink constituting the peelability improving layers D1 to D7 preferably contains a pigment from the viewpoint of hardness (and thus from the viewpoint of improving the function of the fracture initiation points C1 to C4). In this case, the average particle size of the pigment is preferably 0.3 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more. The average particle size of the pigment is preferably 15 μm or less, and more preferably 10 μm or less. The same numerical ranges apply to the average particle size of the particles contained in the above-mentioned coating agent and additive. The average particle size can be measured using a laser diffraction particle size distribution measuring device.

<4. Manufacturing method＞
An example of a method for producing the heat shrinkable film 3 and the packaging container 1 will be described with reference to Fig. 6. However, the heat shrinkable film 3 and the packaging container 1 can be produced by various other methods.

First, a film roll F1 with a film body 4 wound thereon is prepared. The film roll F1 is set in a printing machine 40, and a long film body 4 is unwound from the film roll F1. The film body 4 unwound from the film roll F1 passes through one or more impression cylinders in sequence. At this time, the impression cylinder is pressed against one side of the film body 4, so that ink of a color corresponding to the impression cylinder is transferred. As a result, a printing layer 5 with a predetermined decorative design is laminated on one side of the film body 4. Note that the printing method is not limited to this. After that, the film body 4 (heat-shrinkable film 3) with the printing layer 5 laminated thereon is dried in a dryer as appropriate, and then wound up as a film roll F2. In this manner, the above-mentioned heat-shrinkable film 3 is manufactured.

The heat-shrinkable film 3 wound around the film roll F2 is a continuous series of heat-shrinkable films 3 (hereinafter referred to as unit films) constituting a cylindrical label L (hereinafter referred to as a unit label) to be attached to one container 2. The length of the heat-shrinkable film 3 corresponds to the MD (machine direction) direction, and the width corresponds to the TD (traverse direction) direction. Each unit film included in the heat-shrinkable film 3 wound around the film roll F2 is lined up in the same direction. Therefore, in the next step, the heat-shrinkable film 3 wound around the film roll F2 is cut in the vertical direction according to the width of the unit film. Specifically, the film roll F2 is set in the cutter 41, and the heat-shrinkable film 3 unwound from the film roll F2 is cut in the vertical direction by a cutter to be divided in the horizontal direction. The cutting method is not limited to this. After that, the multiple rows of heat-shrinkable films 3 divided in the horizontal direction are wound up as separate film rolls F3. The heat-shrinkable film 3 wound around each film roll F3 is a continuous vertical row of unit films.

As can be seen from FIG. 4, the horizontal ends of the unit film (left end 4L and right end 4R) are clear and do not have the printed layer 5 formed thereon. Therefore, in the cutter 41, the position of the clear portion extending vertically in the heat-shrinkable film 3 unwound from the film roll F2 is detected by an optical sensor (camera) and the cutting position can be determined.

Next, the film roll F3 is set in the center sealing machine 42. In the center sealing machine 42, the heat-shrinkable film 3 unwound from the film roll F3 is sealed vertically and formed into a cylindrical shape. Specifically, both horizontal ends of the heat-shrinkable film 3 are overlapped, and the overlapped portions are continuously sealed vertically. This produces a cylindrical label L with unit labels arranged vertically in a row, which is then wound up as a film roll F4. There are no particular limitations on the sealing method, and possible methods include solvent sealing, heat sealing, and ultrasonic sealing.

The sealed portion of the heat-shrinkable film 3 at least partially overlaps both clear lateral ends (left end 4L and right end 4R) of the unit film. This makes it easy to check the sealed state.

The center seal machine 42 can also form perforations. In this example, among the above-mentioned perforations L1 to L8, perforations L5 to L8 that extend straight in the vertical direction are formed while the heat-shrinkable film 3 is being unwound from the film roll F3 and wound onto the film roll F4. The method for processing the perforations that extend in the vertical direction is also not particularly limited, and examples of possible methods include laser processing and processing with a perforation blade.

2 and 4, the perforations L5 and L6 are formed continuously along the clear portion (corresponding to the left end 4L and the right end 4R) extending vertically in the heat-shrinkable film 3 or the tubular label L in the vicinity of the clear portion. Therefore, the position of the clear portion is detected by an optical sensor (camera) and the formation position of the perforations L5 and L6 can be determined. On the other hand, the perforations L7 and L8 also extend vertically near the perforations L5 and L6, but are formed only near the lower end 4D. Therefore, the position of the lower end 4D extending horizontally (more precisely, the positions of the lower end 4D and the upper end 4U since the lower end 4D is connected to the upper end 4U at this stage) is detected by the optical sensor (camera), and the formation position of the perforations L7 and L8 can be determined based on this. Although the bottom end 4D (and the top end 4U) partially includes the printed layer 5, it also includes a clear portion, so the position of the bottom end 4D (and the top end 4U) can be detected by detecting the position of the clear portion. Alternatively or in addition to this, the position of the clear middle portion 4M may be detected, and the formation positions of the perforations L7 and L8 may be determined based on this.

Next, the film roll F4 is set in the labeler 43. In the labeler 43, the tubular labels L unwound from the film roll F4 are attached to the individual containers 2. Specifically, the tubular labels L unwound from the film roll F4 are cut horizontally at a predetermined interval in the vertical direction and divided into unit labels. The divided unit labels are then placed on the containers 2 so as to cover them from the outside, and the containers 2 are inserted into the space inside the unit labels. In this state, the unit labels are heat-treated in various ways, such as by blowing hot air or steam. For example, the containers 2 covered with the unit labels may be heated in the tunnel as they pass through it. This causes the unit labels to thermally shrink and adhere to the outer surface of the container 2 along the outer shape of the container 2. In this manner, the packaging container 1 is manufactured.

The labeler 43 can also form the perforations. In this example, of the perforations L1 to L8 described above, the diagonally extending perforations L1 and L2 and the straight horizontal perforations L3 and L4 are formed. The method for processing these perforations L1 to L4 is also not particularly limited, and examples of possible methods include laser processing and processing with a perforation blade. In addition, the perforations L1 to L4 are preferably formed before attaching the cylindrical label L to the container 2.

1 and 4, the perforations L1 and L2 are formed only on the upper part of the unit film or unit label. Therefore, by detecting the position of the clear part included in the upper end 4U (or the upper end 4U and the lower end 4D if the upper end 4U and the lower end 4D are still connected at this stage) with an optical sensor (camera), the vertical formation positions of the perforations L1 and L2 can be determined based on this. Alternatively or in addition to this, the vertical formation positions of the perforations L1 and L2 may be determined based on the position of the clear middle part 4M detected by the optical sensor (camera). Similarly, the vertical formation positions of the perforations L3 and L4 can also be determined based on the positions of the upper end 4U, the lower end 4D and/or the middle part 4M detected by the optical sensor (camera).

The horizontal formation positions of the perforations L1, L2 can also be determined by detecting the positions of the clear portions included in the upper end 4U and lower end 4D using an optical sensor (camera) as a reference. That is, the position of the peelability improving layer D1 can be identified using the positions of the clear portions included in the upper end 4U and lower end 4D as a reference, and the horizontal formation positions of the perforations L1, L2 can be determined using the position of the peelability improving layer D1 as a reference.

5. Modifications
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the following modifications are possible.

＜5-1＞
In the above embodiment, the peelability improving layers D1 to D7 were constituted by a part of the printed layer 5. However, the peelability improving layers D1 to D7 may be constituted by only the above-mentioned coating layer without including the printed layer 5.
＜5-2＞
In the above embodiment, two perforations are configured to form a pair in the cylindrical label L. However, only one perforation may be formed along one tear direction, or three or more perforations running parallel to each other may be formed.

＜5-3＞
In the print layer 5, at least one of the peelability improving layers D1 to D7 may have a shape such as stripes, polka dots, or letters to provide design features.

＜5-4＞
Prior to the heat shrinkage for attaching the cylindrical label L to the container 2, at least one of the breakage starting points C1 to C4 may be preliminarily heat shrunk to thicken and harden the breakage starting point. In this case, the function of the breakage starting point can be improved. In this case, it is preferable to make the total thickness of the breakage starting point after the preliminarily heat shrinkage about 5 to 20% thicker than before the preliminarily heat shrinkage.

＜5-5＞
In the above embodiment, as shown in FIG. 2, the perforations L5 to L8 for peeling the lower film portion 32 are formed in the vicinity of the sealed portion O1 of the tubular label L. However, instead of or in addition to this, for example, as shown in FIG. 7, the perforations L9 to L12 for peeling the lower film portion 32 may be formed in a location other than the vicinity of the sealed portion O1 of the tubular label L. In the example of FIG. 7, the perforations L9 and L10 are aligned laterally with the perforations L1 and L2, respectively, in the lower film portion 32 and extend in the vertical direction. In the vicinity of the perforations L9 and L10, a peelability improving layer D8 is formed in the target portion T2, and a peelability improving layer D9 is formed in the target portion T3. This forms the breakage starting points C5 and C6. On the other hand, the perforations L11 and L12 also extend in the vertical direction in the lower film portion 32, but no perforations are formed in the upper film portion 31 at positions that correspond laterally to the perforations L11 and L12. In the vicinity of the perforations L11 and L12, a peelability improving layer D10 is formed in the target portion T2, and a peelability improving layer D11 is formed in the target portion T3. This forms fracture initiation points C7 and C8.

1 Packaging container 2 Container 20 Main body 21 Bottom surface 22 Body 23 Cap attachment portion 25 Cap 25S Side surface 25T Top surface 3 Heat shrinkable film 31 Film upper portion 31A Opening portion 31B Remaining portion 32 Film lower portion 4 Film main body 4D Lower end 4L Left end 4M Middle portion 4R Right end 4U Upper end 5 Printing layer 5D Lower portion 5U Upper portion 40 Printing machine 41 Cutter 42 Center seal machine 43 Labeler C1 to C8 Breaking start points D1 to D7, D9 to D11 Peelability improving layer D8 Region (peelability improving layer)
F1-F4 Film roll L Cylindrical label L1-L12 Perforation O1 Overlapped part (seal part)
T1 to T3 Target area

Claims (5)

A heat-shrinkable film that is attached to a container as a cylindrical label,
A film body having perforations formed therein;
the perforations extend such that, when the heat-shrinkable film is attached to the container as the tubular label, the tubular label can be peeled off from the container by tearing the tubular label along the perforations;
A peelability improving layer is laminated in the vicinity of the perforation in the target portion of the film body,
The target portion is a portion that becomes an axial end portion of the cylindrical label when the cylindrical label is peeled off.
Heat shrinkable film. The release property improving layer is a printing layer or a coating layer.
The heat shrinkable film of claim 1. The peelability improving layer is laminated discontinuously along the entire circumference of the target portion in the target portion.
The heat shrinkable film according to claim 1 or 2. The peelability improving layer is laminated so as to overlap the perforation in the target portion.
The heat shrinkable film according to claim 1 or 2. A cylindrical label formed from the heat shrinkable film according to claim 1 or 2;
A packaging container comprising: a container to which the tubular label is attached.