Cylindrical label

Abstract

To provide a tubular label that is resistant to tearing from impacts such as those during transport or dropping of the object, and that can be easily opened. [Solution] In the tubular label of the present invention, a base film having a front surface and a back surface is formed into a tube with the back surface facing inward, and a center seal portion is formed by overlapping and bonding a first side end, which is one side end of the base film, and a second side end, which is the other side end of the base film. The center seal portion is formed by folding the first side end inward at a predetermined folding position and bonding the front surface of the folded first side end and the front surface of the second side end. An opening guide line is provided at least one of the upper and lower ends of the tubular label near the folding position side of the center seal portion in the circumferential direction. The opening guide line is not continuous from the upper end to the lower end of the tubular label.

Description

Technical Field

[0001] The present invention relates to a cylindrical label.

Background Art

[0002] Conventionally, for example, a cylindrical label is attached to the body of a container containing a beverage for design display. Such a cylindrical label is formed into a cylinder with the back surface of a single base film facing inward, and a center seal portion is formed by overlapping and adhering the side end portions of the base film. As an opening assistance line for opening the cylindrical label, for example, two perforations extending in the vertical direction (up and down direction) from the upper end to the lower end of the cylindrical label are provided. By pinching and pulling the portion between the two perforations at the upper end or the lower end, the cylindrical label can be opened while tearing the two perforations in the vertical direction. Note that the two perforations may be provided with the center seal portion interposed therebetween (see Patent Documents 1 and 2), or may be provided without interposing the center seal portion.

[0003] Patent Document 3 discloses a cylindrical label in which, in order to make such a center seal portion less noticeable, the first side end portion is folded inward (back surface side) at a predetermined folding position, and the front surface of the folded first side end portion and the front surface of the second side end portion are adhered to form a center seal portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, heat-shrinkable labels, which are widely used as tubular labels, shrink in the circumferential (lateral) direction, and therefore mainly use films that are stretched transversely. These films include films containing polyester resins such as polyethylene terephthalate (PET) that are uniaxially stretched, films containing styrene resins such as polystyrene, composite laminated films of these resins, and other polyolefin resin films. These films are resistant to tearing in the longitudinal direction and resistant to tearing in the transverse direction. Among these, polyethylene terephthalate (PET) films are particularly resistant to tearing in the longitudinal direction and often have poor perforation ease. For this reason, the pitch of the perforation holes is sometimes shortened or the size of the perforation holes is increased to make them easier to open. However, while this improves ease of opening, it presents a problem: the perforations can tear and the cylindrical label can easily break due to impacts during transport or when the object to which the cylindrical label is attached (such as a container) is dropped. In particular, in recent years, due to environmental considerations, containers made of very thin materials have been commercialized to reduce weight, and such containers deform easily due to impact, increasing the risk of the cylindrical label breaking.

[0006] The objective of the present invention is to provide a tubular label that is resistant to tearing from impacts such as those during transport or dropping of an object, and that can be easily opened. [Means for solving the problem]

[0007] In the tubular label of the present invention, a base film having a front surface and a back surface is formed into a tube with the back surface facing inward, and a center seal portion is formed by overlapping and bonding a first side end, which is one side end of the base film, and a second side end, which is the other side end of the base film. The center seal portion is formed by folding the first side end inward at a predetermined folding position and bonding the front surface of the folded first side end to the front surface of the second side end. An opening guide line is provided at at least one of the upper and lower ends of the cylindrical label, near the fold position side of the center seal portion in the circumferential direction. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a tubular label that is resistant to tearing due to impacts such as those during transportation or dropping of an object, and that can be easily opened. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view from diagonally above showing the cylindrical label of the embodiment. [Figure 2] This figure shows the state of the center seal portion of the cylindrical label of the embodiment before adhesion. (a) is a perspective view seen from diagonally below, and (b) is a plan view seen from below. [Figure 3] This figure shows the opening procedure for the cylindrical label of the embodiment. [Figure 4] This is a perspective view showing a modified example of the opening guide line on the cylindrical label of the embodiment. [Figure 5] This is a schematic diagram showing the manufacturing process of a cylindrical label according to the embodiment. [Figure 6] This is another schematic diagram showing the manufacturing process of the cylindrical label according to the embodiment. [Figure 7] This is a schematic diagram illustrating the method for measuring the peel strength of the center seal. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In the drawings, identical or common parts are denoted by the same reference numerals.

[0011] In this specification, "inside" means the inner surface side in the state of the tubular label. The "inside" of the tubular label is also the side that faces the object (adhered body) when the tubular label is used. "Outside" means the opposite direction to "inside" and refers to the outer surface side in the state of the tubular label. Also, the "front surface" means the surface that is on the outside in the state of the tubular label, and the "back surface" means the surface that is on the inside in the state of the tubular label.

[0012] <Tubular label> Referring to FIGS. 1 and 2, in the tubular label 1 of the present embodiment, the substrate film 2 having a front surface and a back surface is formed into a tube with the back surface on the inside, and the first side end portion 21 which is one side end portion (in the width direction) of the substrate film 2 and the second side end portion 22 which is the other side end portion are overlapped and adhered to form a center seal portion 11 (see particularly FIG. 2(b)). Here, the first side end portion 21 is folded (bent) inward at a predetermined folding position 21b, and the front surface of the folded first side end portion 21 (folded portion 212) and the front surface of the second side end portion 22 are adhered to form the center seal portion 11 (triple portion). Such a tubular label has, for example, the same configuration as the tubular label disclosed in the above Patent Document 3 and can be manufactured by the same method.

[0013] The tubular label 1 is not particularly limited as long as it is a tubular label. Examples thereof include a heat-shrinkable tubular label, a self-stretchable tubular label, and the like. A heat-shrinkable tubular label (shrink label) is a tubular label that contracts in diameter when heated to a predetermined temperature or higher and can be attached to an object (adhered body). A self-stretchable tubular label (stretch label, stretch shrink label) is a tubular label that expands in diameter when a stretching force is applied, is inserted into an object in the expanded state, and then restores by releasing the stretching force and can be attached to the object.

[0014] The cylindrical label 1 is attached to an object (adhered body). The object is not particularly limited, and the cylindrical label 1 can be attached to various objects. Representative examples of the object include containers filled with foods such as beverages, containers filled with cosmetics, shampoos, etc. The cylindrical label 1 can be used, for example, as a display label for various containers such as containers filled with beverages, containers filled with foods, containers filled with detergents; a cap seal for protecting the cap of a container; an outer covering for various articles such as plastic containers, dry batteries; a protector for various articles; a bundling body for bundling a plurality of articles, etc.

[0015] (Opening assist line) In the present embodiment, at least one of the upper end and the lower end of the cylindrical label 1, an opening assist line 3 is provided in the vicinity of the folding position (crease line) 21b side of the center seal portion 11 in the circumferential direction. In this specification, "opening" is not limited to the general meaning of the term "opening", and also includes an operation of cutting or excising the cylindrical label.

[0016] Examples of the opening assist line 3 include perforations (sewing threads). A perforation is, for example, an opening assist line formed by a plurality of cut lines arranged continuously at a predetermined pitch. The diameter or length of the holes (cuts) of the perforations is not particularly limited, but is preferably 0.2 to 2.0 mm. The length of the embankment portion of the perforations (interval between adjacent holes) is not particularly limited, but is preferably 0.5 to 2.0 mm. Note that the plurality of holes constituting the perforations can be formed, for example, by intermittently irradiating a film with a laser or the like using a device such as a laser to form intermittent holes or cuts in a perforation shape on the film.

[0017] The opening guide line 3 extends at least in the vertical direction (axial direction A) of the cylindrical label. "Extending in the vertical direction" means that the endpoint of the opening guide line 3 is located towards the center in the vertical direction relative to the starting point (upper or lower end) of the opening guide line 3. For example, it may extend in a straight line along the vertical direction overall, or it may extend diagonally to the vertical direction overall or partially.

[0018] Preferably, the opening guide line 3 does not extend continuously from the top to the bottom of the cylindrical label 1. If the opening guide line extends continuously from the top to the bottom of the cylindrical label, and the perforations are made easier to open (break) by shortening the pitch of the perforations or increasing the size of the perforations, the cylindrical label is more likely to be opened by the opening guide line breaking due to impacts such as when transporting or dropping the object to which the cylindrical label is attached. In contrast, if the opening guide line does not extend continuously from the top to the bottom of the cylindrical label, even if the perforations are made easier to open (break), it is possible to prevent the opening guide line from breaking and the cylindrical label from being completely opened due to impacts such as when transporting or dropping the object to which the cylindrical label is attached. In addition, although various designs are printed on the cylindrical label, it is possible to prevent the design quality from being reduced by the perforations (holes, cuts) that have become larger due to heat shrinkage overlapping with the printed design.

[0019] The length of the opening guide line 3 is preferably as short as possible, within a range that allows for easy breakage of the opening guide line 3 as the starting point for opening the cylindrical label 1 (peeling off the center seal portion 11). A shorter opening guide line makes it more reliable to prevent the opening guide line from breaking and the cylindrical label from being opened due to impacts such as during transport or dropping of the object to which the cylindrical label is attached. The length of the opening guide line 3 in the vertical direction (axial direction of the cylindrical label 1) is not particularly limited, but is preferably about 5 to 30 mm. Furthermore, the length of the opening guide line 3 in the vertical direction is preferably 20% or less, and more preferably 15% or less, of the length of the cylindrical label 1 in the vertical direction (axial direction).

[0020] The distance (circumferential distance) between the opening guide line 3 and the center seal portion 11 is not particularly limited, but is preferably about 5 to 15 mm. If the distance is too short, the second and third steps of the opening operation described below may become difficult, and the guide line may be included in the center seal portion 11 due to manufacturing errors, rendering it ineffective as an opening guide line. If the distance is too long, the second step of the opening operation described below may become difficult, or the operation time may increase.

[0021] Furthermore, in order to guide the direction in which the label is peeled off when performing the opening procedure described below, an opening guidance indicator 30, such as an arrow, may be printed on the center seal portion 11 side of the opening guide line 3 of the cylindrical label 1.

[0022] In the cylindrical label 1 of this embodiment, it is preferable that the center seal portion 11 is sealed with an adhesive force that allows it to be peeled off with an appropriate peel strength when picked up with fingers. To obtain such peel strength, it is preferable to seal the center seal portion 11 by welding (by dissolving the surface with a solvent selected from the following and joining them). Suitable solvents include pentane, n-hexane, diethyl ether, heptane, octane, cyclohexane, isopropyl acetate, n-butyl acetate, n-propyl acetate, carbon tetrachloride, xylene, ethyl acetate, toluene, benzene, methyl methyl ketone, methyl acetate, methylene chloride, tetrahydrofuran, 1,3-dioxolane, acetone, isopropyl alcohol, ethanol, methanol, and others, with 1,3-dioxolane, methyl acetate, and cyclohexane being particularly preferred.

[0023] Suitable materials for the weldable base film 2 include polystyrene resins (styrene-butadiene copolymers), polyester resins containing amorphous components (particularly those containing ethylene terephthalate units, in which the glycol component is modified with 1,4-cyclohexanedimethanol or neopentyl glycol to make it amorphous, or the dicarboxylic acid component is modified with isophthalic acid or adipic acid to make it amorphous), and cyclic polyolefins.

[0024] The peel strength of the center seal portion 11 is preferably 1 to 10 N / mm. Examples of base films 2 capable of forming a center seal portion 11 with such peel strength include PET films (e.g., Mitsubishi Chemical Corporation's Hishipet LX21S), OPS (oriented polystyrene) films (e.g., Takiron CI Corporation's Bonset BS55S), and PET / PS (polystyrene) / PET laminated films (e.g., Gunze Corporation's Fancy Wrap HST). Furthermore, the peel strength of the center seal portion formed by these films was measured using the following measurement method. The measurement results are shown in Table 1.

[0025] (Method for measuring peel strength) Using the above film, a cylindrical label with a center seal was created in the same manner as above (and by the method described later). A cylindrical label was cut at the position indicated by the dotted line in Figure 7 to create a test specimen including the center seal. Next, sections A and B shown in Figure 7 were clamped with a chuck, and the adhesive portion (center seal portion) was pulled in the peeling direction (the direction in which A and B separate). The load (N) during this process was measured to determine the peel strength. The measurement conditions were as follows. Measuring instrument: Tensile testing machine Specimen dimensions: TD (horizontal direction) 70mm, MD (vertical direction) 15mm Test speed: 200 mm / min

[0026] [Table 1]

[0027] [Opening operation] Now, referring to Figure 3, the operation (steps) for opening the cylindrical label 1 of this embodiment will be described.

[0028] (Step 1) First, grasp the cylindrical label 1 from the opening guide line 3 towards the center seal portion 11 at the lower (or upper) end and pull it diagonally upward (in the direction of the white arrow in Figure 1) to peel a portion of the lower end of the cylindrical label 1 from the object 4. At this time, break the cylindrical label 1 at the opening guide line 3 (Figure 3(a)).

[0029] (Step 2) Furthermore, by pulling the gripped portion (grip portion) of the cylindrical label 1 diagonally upward, the cylindrical label 1 is first torn at the first tear portions 31a and 31b (Figure 3(b)). The first tear portion 31a extends circumferentially from the upper end of the opening guide line 3 to the center seal portion 11. The opening guide line 3 may not be cut all the way to the end (end point), and the cylindrical label 1 may be torn from the middle of the opening guide line 3 in the direction of the center seal (first tearing portion 31a, 31b). Furthermore, if the base film 2 constituting the tubular label 1 is a film with good transverse tearing properties (a film with poor longitudinal tearing properties and good transverse tearing properties, such as those used for shrink labels), the tubular label will be torn simply by pulling the gripping portion diagonally upward in this manner, so that the first tearing portion 31a extends circumferentially to the center seal portion 11. However, as shown in the modified example in Figure 4, the opening guide line 3 may be provided at an angle (Figure 4(a)) or curved (made R-shaped) so that the opening guide line 3 moves closer to the center seal portion 11 as it moves away from the upper (or lower) end, thereby guiding the first tear portion 31a to extend circumferentially to the center seal portion 11. Alternatively, as shown in Figure 4(c), the opening guide line 3 may be composed of a perforation 3a extending from the lower (or upper) end and a plurality of diagonally extending cuts 3b thereafter, thereby guiding the first tear portion 31a to extend circumferentially to the center seal portion 11.

[0030] (Step 3) Furthermore, by pulling the gripped portion of the cylindrical label diagonally upward, the second side end 22 (single layer) of the center seal portion 11 is torn at the tearing portions 32a and 32b, and at the same time, the first side end 21 is peeled away from the second side end 22 (above the tearing portion 32a) (Figure 3(c)). Furthermore, the portion of the second end 22 above the first tear portion 31a (towards the center in the vertical direction) is integrated with the film on the side of the circumferential opening guide line 3. Therefore, even if the gripping portion (the portion of the second end 22 below the first tear portion 31a) is pulled up, the portion of the second end 22 above the first tear portion 31a remains in place, and the second end 22 is torn at the tear portions 32a and 32b. On the other hand, the first end portion 21 is integral with the film on the side of the circumferential opening guide line 3, and when the gripping portion is pulled up, it is pulled up together with the peeled film. In this embodiment, since the base end 211 at the first end 21 is not bonded to the folded portion 212, when the gripping portion is pulled up, the base end 211 is pulled away from the folded portion 212, and as a result, the folded portion 212 is pulled away from the folded position 21b. In this way, a force in the peeling direction acts on the adhesive surface between the first end 21 (folded portion 212) and the second end at the center seal portion 11. As a result, the first end 21 is easily peeled away from the second end 22.

[0031] Furthermore, if the back surface of the (unfolded) first end 21 and the front surface of the second end 22 are bonded together at the center seal portion 11, it is difficult to peel the first end from the second end. In this case, during the operation of the second step described above, both films bonded at the center seal portion will tear beyond the center seal portion, and the two films will not be separated. For this reason, it is considered that opening the cylindrical label will be difficult. Furthermore, even if the first end portion 21 is folded and glued as in this embodiment, if the opening guide line 3 is located on the opposite side from this embodiment (near the fold position 21b of the center seal portion 11 in the circumferential direction of the cylindrical label 1), it is difficult to peel the first end portion from the second end portion. In this case, in the second step described above, the label is torn circumferentially from the upper end (or partway along) of the opening guide line 3 toward the center seal portion 11, and even if it tears up to the base end portion 211, the force then has nowhere to go, and the force is not transmitted to the fold portion 212 or the second end portion 22, and the tear stops at the fold position 21b (see Figure 2(b)). For this reason, the third step described above is not performed, and it is considered that opening the cylindrical label becomes difficult.

[0032] (Step 4) Furthermore, by lifting the gripping portion of the cylindrical label 1 from the state shown in Figure 3(c), the first end portion 21 can be easily peeled away from the second end portion 22 of the center seal portion 11. This allows the cylindrical label 1 to be completely peeled away from the object 4. In this case as well, in the same manner as described above, a force in the peeling direction acts on the adhesive surfaces of the first end portion 21 (folded portion 212) and the second end portion 22 in the center seal portion 11, so that the first end portion 21 can be easily peeled away from the second end portion 22.

[0033] In this embodiment, as described above, by pulling up the center seal portion 11 side from the opening guide line 3 at the lower end (or upper end) of the cylindrical label 1, the center seal portion 11 can be peeled off to the upper end, making it possible to easily open (remove from the container) the cylindrical label 1. In this embodiment, the perforations in the tubular label only need to serve as the starting point for opening, and opening is mainly performed by peeling off the center seal portion 11. Therefore, there is no need to provide perforations that extend from the top end to the bottom end, as is the case with conventional perforations for cutting. As a result, it is possible to provide a tubular label that is less likely to tear due to impacts such as when transporting or dropping the object. Furthermore, the cylindrical label of this embodiment can be easily opened with a single action by pulling up near the opening guide line 3. Furthermore, in this embodiment, the cylindrical label does not separate when opened, as in the case where the label is pinched and pulled between the two perforations that extend vertically from the top to the bottom of the cylindrical label. The cylindrical label remains a single piece after opening. Therefore, the cylindrical label is easy to handle after opening.

[0034] It is also conceivable to omit the opening guide line 3 and instead provide a small non-adhesive area at the lower or upper end of the center seal portion 11, using this non-adhesive area as the starting point for opening. However, if the cylindrical label is attached to an object using the heat-shrinking properties of a shrink label or similar, providing a non-adhesive area makes the center seal portion of the cylindrical label more prone to peeling or tearing starting from the non-adhesive area due to heat shrinkage during attachment. For this reason, it is desirable to provide the opening guide line 3 described above and use it as the starting point for opening.

[0035] (Structure of cylindrical labels, etc.) The tubular label 1 is generally provided in the form of a long tubular label continuous, formed by shaping a long base film into a tube. The long tubular label continuous, wound on a roll, is pulled out and cut to a predetermined length just before being attached to an object (for example, a beverage container such as a PET bottle), thereby obtaining one tubular label 1. The tubular label of this embodiment may be in the form of a continuous long tubular label as described above, or it may be in the form of a single independent label. Note that while the cylindrical label 1 is cylindrical (or rectangular, depending on the shape of the object) when in use, as shown in Figure 1, it may be folded into a flat shape before use. Furthermore, the base film 2 before being formed into a tubular shape is, for example, rectangular in shape with a predetermined width and length.

[0036] At a position a predetermined width away from the first side edge 21a, which is the lateral edge of the first side edge 21, toward the second side edge 22, there is a fold line (folding position) 21b that extends vertically, and the first side edge 21 of the base film 2 is folded in with its back surface facing inward (so that the back surfaces of the base film 2 are in contact with each other). As the first end portion 21 is folded in this way, when the base film 2 is formed into a tube, the front surface of the first end portion 21 and the front surface of the second end portion 22 face each other (see Figure 2(b)). A solvent (or adhesive) is applied in a strip in the vertical direction to at least one of the front surfaces of the first end 21 and the second end 22 of the base film 2, and the front surfaces of the first end 21 and the second end 22 of the base film 2 are bonded together in a strip via the solvent (or adhesive).

[0037] The width (length in the circumferential direction) of the center seal portion 11, that is, the width of the adhesive portion, is not particularly limited, but is usually 2 mm to 10 mm, and preferably 3 mm to 7 mm. Furthermore, the folded first end portion 21 only needs to be adhered to the front surface of the second end portion 22, either partially or entirely, to its front surface. For example, the center seal portion 11 may be formed by bonding the front surface of the first side end 21 to the front surface of the second side end 22 between a position near the first side edge 21a and a position near the fold line 21b (in this case, a part of the front surface of the first side end 21 is bonded to the second side end 22). It is preferable that the bonding extends to the edge of the fold portion 21b. Alternatively, the center seal portion 11 may be formed by bonding the front surface of the first side end 21 to the front surface of the second side end 22 over the entire area between the first side edge 21a and the fold line 21b (in this case, the entire front surface of the first side end 21 is bonded to the second side end 22).

[0038] In this embodiment, the center seal portion 11 of the tubular label 1 is formed by bonding the front surface of the first side end portion 21, which is folded inward into the base film 2, to the front surface of the second side end portion 22 of the base film 2. Therefore, in the tubular label 1 of this embodiment, both the first side edge 21a and the second side edge 22a of the base film 2 are located on the inside of the tubular label 1. As a result, the first side edge 21a of the base film 2 is not visible externally, providing a tubular label 1 with excellent aesthetics. Furthermore, the first side end 21 (double layer), which is formed by overlapping the base end 211 and the folded portion 212, covers the outside of the adhesive surface of the center seal portion 11. As a result, the adhesive marks of the center seal portion 11 are not easily visible externally, thus providing a tubular label 1 with superior aesthetics. Note that the first side edge 21a and the second side edge 22a may be aligned, or either the first side edge 21a or the second side edge 22a may be slightly extended.

[0039] (Base film) The material of the base film 2 can be appropriately selected depending on the application of the tubular label 1 in this embodiment.

[0040] For example, when the tubular label 1 is used as a heat-shrinkable tubular label (shrink label), the base film 2 is a heat-shrinkable film that can shrink significantly in the transverse direction (circumferential direction when it is a tubular label). The heat-shrinkable film may shrink or expand slightly in the longitudinal direction (direction perpendicular to the transverse direction within the plane of the film).

[0041] Examples of heat-shrinkable films include transversely stretched uniaxial films containing mainly polyester resins such as polyethylene terephthalate (PET), olefin resins such as polypropylene (PP), styrene resins such as styrene-butadiene copolymers, cyclic olefin resins, and vinyl chloride resins.

[0042] The thermal shrinkage rate of the heat-shrinkable film is not particularly limited as long as it is sufficient to adhere to the object after thermal shrinkage, but the thermal shrinkage rate in the lateral direction (shrinkage rate when immersed in 90°C hot water for 10 seconds) should be approximately 30% or more, and is particularly preferably 50% or more.

[0043] Furthermore, when the tubular label 1 is used as a self-stretchable tubular label, the base film 2 is a self-stretchable film that can stretch in the lateral direction. Examples of self-stretchable films include films containing olefin resins such as polyethylene, and thermoplastic resins such as ethylene vinyl acetate copolymer. However, in the case of self-stretchable tubular labels, the base film 2 may have not only self-stretchability but also heat-shrinkability.

[0044] In this embodiment, the base film 2 is preferably a film that is difficult to tear in the longitudinal direction (the axial direction when it is a tubular label 1) (for example, a longitudinal tear force of 0.5 N or more, preferably 1.0 N or more). Furthermore, the base film 2 is preferably a film that is easily torn in the transverse direction (circumferential direction when it is a tubular label 1) (for example, a transverse tear force of less than 0.15 N, preferably less than 0.1 N). Furthermore, it is more preferable that the base film 2 is difficult to tear in the longitudinal direction and easy to tear in the transverse direction. In this case, the circumferential tearing in the second step described above can be carried out more reliably. Furthermore, for the base film 2 used for the tubular label 1 (heat-shrinkable tubular label), a film that is stretched transversely and has molecules oriented transversely is often used, making it difficult to tear in the longitudinal direction.

[0045] Examples of films that are difficult to tear in the longitudinal direction and easy to tear in the transverse direction include OPS film (a heat-shrinkable stretchable film containing a styrene-based resin such as the styrene-butadiene copolymer), PET film (a heat-shrinkable stretchable film containing a polyester-based resin having amorphous components), and PET / PS / PET laminated film (a heat-shrinkable multilayer stretchable film having layers containing the polystyrene-based resin between layers containing the polyester-based resin). Furthermore, the tear strength (N) in the longitudinal (MD) and transverse (TD) directions of these films was measured using the following measurement method. The measurement results are shown in Table 2.

[0046] (Method for measuring tearing force) Referenced test method: JIS K 7128-1 For each test specimen of the film, both in the transverse (TD) and longitudinal (MD) directions, a slit was made in the center of the film and then it was torn. Tear propagation = Tear force of the test specimen (N) / Thickness of the test specimen (mm)

[0047] [Table 2]

[0048] The tubular label 1 of this embodiment is attached to the object in an appropriate manner. If the tubular label 1 in this embodiment is a heat-shrinkable tubular label (shrink label), the tubular label 1 can be attached to the object by fitting the tubular label 1 onto the object and then heating it to a predetermined heat shrinkage temperature (for example, 80°C to 100°C). If the tubular label 1 in this embodiment is a self-stretching tubular label, the tubular label 1 can be attached to the object by expanding its diameter, fitting it onto the object, and then releasing the expansion.

[0049] The base film 2 may consist of a single layer film (single-layer film) or a film in which two or more layers are laminated (laminated film). If the base film 2 is a laminated film, each layer of the laminated film can be arbitrarily selected. The materials of each layer may be substantially the same or different.

[0050] When the tubular label 1 is used as a heat-shrinkable tubular label, the laminated film can be a laminated film in which two or more types of resins are laminated and heat-shrinkable properties are imparted by stretching, or a laminated film in which a heat-shrinkable film layer is laminated with an insulating layer or other functional layer. When the tubular label 1 is used as a self-stretchable tubular label, the laminated film can be a laminated film in which two or more self-stretchable layers are laminated, or a laminated film in which a heat insulating layer or other functional layer is laminated to a self-stretchable film layer, etc.

[0051] Examples of insulating layers include foamed resin layers and nonwoven fabrics.

[0052] In the center seal portion 11 of the tubular label 1 of this embodiment, the front surfaces of the first end 21 of the base film 2 (the front surface of the first end 21 and the front surface of the second end 22) are bonded together. Therefore, even when a laminated film with different materials for the outermost and innermost layers is used as the base film 2, the same materials are bonded together at the bonding surface, thus forming a center seal portion 11 with excellent adhesive strength. Welding, which involves melting and joining the same materials, is particularly preferred.

[0053] The thickness of the base film 2 is not particularly limited, but is usually 20 μm to 100 μm. However, the thickness of the base film 2 with a heat insulating layer is usually thicker, for example, 80 μm to 300 μm.

[0054] (Printing layer) A printing layer may be provided on the back surface of the base film 2 for displaying the design. The printing layer may have a design printing layer that displays text or images, and a background printing layer (for example, a solid white printing layer) laminated on the back side of the design printing layer to make the text or images look nice.

[0055] In this embodiment, the printed layer can also be provided on the back surface of the first side end 21 of the base film 2. In this embodiment, the front surfaces of the base film 2 are bonded together to form the center seal portion 11, and the back surface of the first side end 21 is not bonded. The printed layer is preferably provided on the back surface of the first side edge 21, and more preferably on the entire back surface (from the first side edge 21a to the second side edge 22a). In the center seal portion 11, when the back surface of the (unfolded) first end portion 21 and the front surface of the second end portion 22 are bonded together, even if a printing layer is provided on the back surface, the printing layer cannot be provided in an area slightly wider than the bonded area on the back surface of the first end portion. As a result, a thin, transparent band without a printing layer exists along the opposite side of the first edge of the center seal portion, which causes the center seal portion to stand out. By extending the printing layer to the back surface of the first end portion 21, the aforementioned strip-like portion is not formed, and the printing layer is continuous on both sides of the center seal portion 11 in the circumferential direction, making the center seal portion 11 less conspicuous. This makes it possible to provide a tubular label 1 with superior aesthetics.

[0056] Furthermore, a transparent resin layer (cover layer) may be provided to cover the back surface of the printed layer for purposes such as protecting the printed layer.

[0057] When a printing layer is provided on the back surface of the base film 2, the base film 2 is a film with excellent light transmittance (a colorless transparent film or a slightly colored transparent film). Furthermore, it is preferable that the printed layer be provided only on the back surface of the base film 2. This is because if the printed layer is provided on the front surface of the base film 2, the adhesion between the front surfaces of the base film 2 (the front surface of the first end 21 and the front surface of the second end) will be poor.

[0058] However, a printed layer, a slippery overcoat layer, a matte coat layer, etc., may be appropriately provided on the surface of the base film. In this case, in order to maintain the adhesion of the center seal portion 11 by welding, it is preferable not to provide a printed layer, etc., in the area where the center seal portion 11 is formed, or to provide it very thinly. Also, if an adhesive is used, it is necessary to select a coating agent that has good adhesion to the adhesive.

[0059] (Color adjustment of the center seal area) In the tubular label 1 of this embodiment, if a printing layer is provided on the back side of the base film, the center seal portion 11 (first end portion 21) to which the base film 2 is bonded becomes a portion where three printing layers overlap (triple portion), and is adjacent to a portion where only one printing layer exists (single portion). Here, a difference in color intensity occurs between the triple-layered section and the single-layered section, and this difference in intensity may make the center seal section 11 (first side end 21) stand out, which is undesirable in terms of appearance. Therefore, it is desirable to further improve the aesthetic appearance of the cylindrical label by eliminating this difference in intensity.

[0060] To minimize the noticeable difference in shade between the triple-layered and single-layered sections, it is preferable to keep the color difference (ΔE) between the triple-layered and single-layered sections below 7. This makes it possible to provide a tubular label 1 with excellent aesthetics where the difference in shade between the triple-layered and single-layered sections is not noticeable. In this specification, the color difference (ΔE) is the color difference expressed by the color difference formula CIE DE2000.

[0061] For example, by setting the dot area ratio of the triple-layered printing layer to 60% or less of the dot area ratio of the single-layered printing layer, the color difference (ΔE) between the triple-layered and single-layered sections can be reduced to less than 7.

[0062] Furthermore, the rigidity of the film may be made different on both sides of the fold line 21b (the base end 211 and the folded portion 212) to facilitate the folding of the first side end 21 at the fold line 21b. To facilitate folding the first side edge 21 at the fold line 21b, the amount of printed layer (halftone area ratio) provided on the base film 2 on both sides of the fold line 21b may be made different. For example, the amount of printed layer on both sides of the fold line 21b may be made different by printing the solid white area on the base edge 211 twice and the solid white area on the folded portion 212 once. To facilitate the folding of the first side edge 21 and to make the density difference between the triple-layered and single-layered sections less noticeable, the base film 2 may be modified by reducing the dot area ratio of the printed layer only in the folded portion 212, thereby creating a difference in the amount of printed layer on both sides of the fold line 21b, and making the color difference (ΔE) between the triple-layered and single-layered sections less than 7. The dot area ratio is a percentage that represents the proportion of the dot area per unit area in a dot grayscale image, and is an indicator of the degree of darkness in a dot-printed material.

[0063] <Manufacturing of cylindrical labels> Referring to Figures 5 and 6, the manufacturing method of the tubular label 1 of this embodiment includes a folding step and a center sealing step in that order. Note that the manufacturing method of the tubular label 1 of this embodiment may include a dispensing step before the folding step.

[0064] In the unwinding process, the long base film 2 (which may be a printed film slit to a predetermined width, or a plain roll of film) that has been wound onto a roll is unwinded from the roll (Figures 5(a) and 6).

[0065] In the folding process, the first side edge 21 of the base film 2 is folded inward (towards the back side) at a predetermined folding position 21b (Figure 5(b)). The folding process is carried out, for example, by folding the first side edge 21 (folded portion 212) of the base film 2 (which may be a printed film slit to a predetermined width, or a plain raw film) to the back side along the fold line 21b, as shown in Figure 6. Furthermore, as shown in Figure 6, it is preferable to pass the folded portion 212 of the base film 2, in which the first side end 21 is folded to the back side, between a pair of nip rolls 51 and apply nip pressure so that the folded portion 212 is maintained in a state where it is sufficiently folded along the fold line 21b until the center sealing process.

[0066] In the center sealing process, the front surface of the folded first end portion 21 (folded portion 212) and the front surface of the second end portion 22 are bonded together (Figure 5(c)). In the center sealing process, first, a solvent (or adhesive) is applied to at least one of the front surfaces of the folded first end portion 21 (folded portion 212) and the second end portion 22. For example, as shown in Figure 6, the solvent may be sprayed from the tip of the nozzle 6 onto the surface of the second end portion 22, thereby applying the solvent to the surface of the second end portion 22. With the front surface of the folded portion 212 and the front surface of the second end portion 22, both coated with a solvent (or adhesive), overlapping so that they are in contact with each other, the base film 2 is transported so that the adhesive surfaces pass between the pair of nip rolls 52, thereby bonding the front surface of the folded portion 212 and the front surface of the second end portion 22, and forming the center seal portion 11.

[0067] The manufacturing method of the tubular label 1 of this embodiment further includes a step of forming an opening guide line (not shown). In the opening guide line formation process, an opening guide line 3 is formed. The opening guide line formation process may be performed, for example, between the dispensing process and the folding process, or between the folding process and the center sealing process. [Examples]

[0068] <Color difference and appearance verification test> In a cylindrical label with a printed layer formed on the reverse side, a test was conducted to investigate the relationship between the color difference (ΔE) between the triple-layered section and the other sections (single-layered section) and the overall appearance (degree of visibility of the color difference) in order to determine the conditions for minimizing the visibility of the difference in shade between the center seal section (triple-layered section) and the other sections (single-layered section).

[0069] In the test, cylindrical labels having a center seal portion (triple layer) and other portions (single layer) as described in the above embodiment were created using a base film on which printed layers of each of the five colors C (cyan), M (magenta), Y (yellow), K (black), and W (white) were formed. For each color, base films were prepared with halftone dot area ratios ranging from 100% (solid printing) to 10% in 10% increments, and these were used to create tubular labels.

[0070] For each cylindrical label, the color difference (ΔE) between the triple-layered and single-layered sections was measured, and the appearance was judged by visual evaluation. The color difference (ΔE) between the triple-layered and single-layered sections was calculated from the measured values ​​of lightness L, chromaticity a, and chromaticity b of the single-layered and triple-layered sections. In judging the appearance, if there was a noticeable difference in density between the triple-layered and single-layered sections, resulting in an aesthetic problem, it was judged as having a problem (indicated by "×" in Table 1). If there was no noticeable difference in density between the triple-layered and single-layered sections, resulting in no aesthetic problem, it was judged as having no problem (indicated by "○" in Table 1). Table 3 shows the measurement results for ΔE and the results of the appearance evaluation.

[0071] [Table 3]

[0072] As shown in Table 3, when the printed layer color is C, M, Y, and K, the ΔE value was 6.5 or less in all cases where the halftone area ratio was between 10% and 100%. Visual evaluation showed that the density difference between adjacent areas was not noticeable, and there were no aesthetic problems. On the other hand, when the color of the printed layer was white (W), the value of ΔE was 10 or more in all cases where the halftone area ratio was between 10% and 100%, resulting in noticeable density differences between adjacent areas in visual evaluation, which presented an aesthetic problem.

[0073] Next, to investigate the ΔE conditions necessary to maintain the appearance of the label without noticeable differences between the triple-layered and single-layered sections, the dot area ratio of the printed layer in the triple-layered section was varied between 80% and 30%, and ΔE was similarly measured and evaluated visually. The results are shown in Table 4.

[0074] [Table 4]

[0075] From the evaluation results shown in Table 4, it can be seen that if the dot area ratio of the printing layer (W printing) in the triple layer (center seal area) is 60% or less of that of the single layer, the boundary between the single and triple layers becomes less noticeable, resulting in a better appearance. However, if the dot area ratio of the W printing is reduced to 30%, the boundary between the single and triple layers becomes noticeable, resulting in a poor appearance. Therefore, it is preferable to set the dot area ratio of the W printing in the triple layer to around 40-60%.

[0076] Furthermore, the results shown in Tables 3 and 4 suggest that by reducing the color difference ΔE between the single-layer and triple-layer sections to less than 7, the difference in shade at the boundary between the single-layer and triple-layer sections becomes less noticeable, resulting in a better appearance for the cylindrical label.

[0077] The present invention is not limited to the embodiments described above and can be modified in various ways. Two or more embodiments selected from the various embodiments described above may be combined as appropriate, or at least one configuration (part of a configuration) selected from the various embodiments described above may be replaced with a part of a configuration of another embodiment.

[0078] <Summary> The embodiments of the present invention described above are listed below as examples.

[0079] (1) A cylindrical label having a front surface and a back surface, in which the base film is formed into a cylindrical shape with the back surface facing inward, and a first side end, which is one side end of the base film, and a second side end, which is the other side end, are overlapped and bonded together to form a center seal portion, The first side end is folded inward at a predetermined folding position, and the front surface of the folded first side end and the front surface of the second side end are bonded together to form the center seal portion. An opening guide line is provided at at least one of the upper and lower ends of the cylindrical label, near the folding position side of the center seal portion in the circumferential direction. The aforementioned opening guide line is not continuous from the top end to the bottom end of the cylindrical label.

[0080] (2) The cylindrical label as described in (1), wherein the opening guide line is not continuous from the top end to the bottom end of the cylindrical label.

[0081] (3) A tubular label as described in (1) or (2), wherein the longitudinal tear force is 1.0 N or more and the transverse tear force is less than 0.1 N.

[0082] (4) A cylindrical label according to any one of (1) to (3), wherein a printing layer is provided on the back surface of the base film, and the printing layer extends to the back surface of the first side end.

[0083] (5) A cylindrical label according to any one of (1) to (4), wherein the color difference (ΔE) between the center seal portion and the portion other than the center seal portion is less than 7. [Explanation of Symbols]

[0084] 1. Cylindrical label 11 Center seal section (triple section) 12. Parts other than the center seal (single layer) 2. Base film 21 First side end 211 Proximal end 212 Folded section 21a 1st side edge 21b Folding position (fold line) 22 Second side end 22a 2nd side edge 3. Opening guide line 3a Perforation 3b Notch 30 Opening guidance display 31a, 31b First tear section 32a, 32b Second tear section 4. Object 51, 52 Nip Roll 6 nozzles A-axis

Claims

1. In a cylindrical label having a front surface and a back surface, the base film is formed into a cylindrical shape with the back surface facing inward, and a center seal portion is formed by overlapping and bonding a first side end, which is one side end of the base film, and a second side end, which is the other side end of the base film, The first side end is folded inward at a predetermined folding position, and the front surface of the folded first side end and the front surface of the second side end are bonded together to form the center seal portion. A cylindrical label wherein an opening guide line is provided at at least one of the upper and lower ends of the cylindrical label, near the fold position side of the center seal portion in the circumferential direction.

2. The cylindrical label according to claim 1, wherein the opening guide line is not continuous from the top end to the bottom end of the cylindrical label.

3. The cylindrical label according to claim 1, wherein the longitudinal tear force is 1.0 N or more and the transverse tear force is less than 0.1 N.

4. The cylindrical label according to claim 1, wherein a printing layer is provided on the back surface of the base film, and the printing layer extends to the back surface of the first end.

5. The cylindrical label according to claim 1, wherein the color difference between the center seal portion and the portion other than the center seal portion is less than 7.

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