JP6534841B2 - Lid label and package - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a lid label for covering an outlet of a packaging material, and a package provided with the same.

  For example, in a wet tissue package containing a wet tissue, a lid label is attached so as to cover an outlet for taking the wet tissue out of the package bag. The lid label is releasably and releasably affixed to the packaging bag, and after the wet tissue is taken out of the packaging bag, the lid label is reattached to the packaging bag to take out the removal port. It can be occluded and the drying of the wet tissue remaining in the packaging bag can be prevented.

  Although a pressure-sensitive adhesive layer is provided on the back of the lid label, a solvent-based pressure-sensitive adhesive is used as the pressure-sensitive adhesive, and the change in adhesive strength is small at normal temperature storage, and the sealing property is excellent. In addition, it has the advantage of being easy to peel off. However, for example, when stored in a warehouse for a long time, there is a problem that the adhesive strength is increased and it becomes difficult to peel off at the time of opening.

JP 2008-44632 A

  Therefore, the present invention is made in view of the above-mentioned conventional problems, and to provide a lid label for lid that can maintain good openability with small change in adhesion strength even with long-term storage, and a package provided with the same. It will be an issue.

  The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and set the type of adhesive layer on the back surface to a UV curable hot melt adhesive instead of a solvent type and to adjust the gel fraction within a predetermined range. It has been found that the time-dependent change in adhesive strength can be reduced by That is, the lid label according to the present invention is a lid label that is releasably and releasably attached to a packaging material so as to cover a takeout opening for taking out the packaged object, and the adhesive on the back surface Is a UV curable hot melt pressure sensitive adhesive, and has a gel fraction of 65 to 80% by weight.

  In the lid label of this configuration, the adhesive on the back side is a hot melt adhesive that is not a solvent type but an ultraviolet curing type, and the gel fraction is 65 to 80% by weight. Even when stored for a long time, etc., the change with time of the adhesive strength of the pressure-sensitive adhesive is small, so that it can be peeled off smoothly from the packaging material even after the long-term storage.

  In particular, the adhesive strength to the packaging material after storage at 50 ° C. for one month is preferably 1.0 to 4.0 N / 25 mm, and both the sealing property and the opening property can be achieved.

  Moreover, it is preferable that the adhesive strength to the packaging material after 24-hour storage at room temperature is 0.5-3.5 N / 25 mm, and the still more favorable sealing property and openability are obtained.

  The package according to the present invention is provided with the lid label as described above.

  As described above, by using a UV curable hot melt adhesive as the adhesive on the back side and setting the gel fraction to 65 to 80% by weight, the adhesive strength is excessive even when stored for a long time in a warehouse etc. There is no increase in size, good openability can be maintained, and sealability can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the package body in one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The top view which shows the package body in one Embodiment of this invention. (A) And (b) is principal part sectional drawing which shows the layer structure of the label for lids.

  Hereinafter, a package according to an embodiment of the present invention and a lid label used therefor will be described with reference to FIGS. 1 to 3. The package 1 shown in FIGS. 1 and 2 is a soft package in which various packages are packaged by means of a soft packaging material by pillow packaging or the like, and the package 1 is used as a packaging material for packaging the package. , And a lid label 2 attached thereto. The form, type, shape and the like of the package are not particularly limited, but as an example, a package in which a wet tissue as a material to be packaged is hermetically packaged by the flexible packaging bag 1 can be exemplified. In the case of this package, the wet tissue (wet sheet), which is the content, is formed in a substantially rectangular shape and accommodated in a large number of laminated layers. Therefore, the laminate of the wet tissue has a substantially rectangular parallelepiped shape. The package formed by pillow packaging also has a substantially rectangular parallelepiped shape.

  A take-out port 10 for taking out the package from the package bag 1 is formed on the upper surface of the packaging bag 1, and a cover label 2 covers the take-out port 10. In FIG. 1 etc., the outer edge of the extraction opening 10 is shown by a broken line, and the portion inside the broken line is the extraction opening 10. The takeout port 10 may be configured to be opened in advance in the packaging bag 1, or various cutting lines may be formed in the packaging bag 1, and the inner portion of the packaging bag 1 surrounded by the cutting lines may be It may be configured to be opened by being separated from the outer part while being attached to the lid label 2. The score line may be various break lines including half cuts, and may be, for example, a circular shape, an elliptical shape, a rectangular shape, or a U-shape. The position of the outlet 10 is preferably at the center of the upper surface. Moreover, although the shape of the taking-out opening 10 is arbitrary, since the upper surface of the packaging bag 1 is a rectangle, it is preferable to set it as a long shape along the long side. Although not shown, a back-pasted portion (heat seal portion) is formed on the bottom of the packaging bag 1.

  The packaging film which comprises the packaging bag 1 is not specifically limited, A single layer or a multilayer synthetic resin film, A laminated film which laminated metal foils, such as aluminum foil, on this synthetic resin film, A laminated film of a synthetic resin and paper etc. , Various flexible films can be used. The packaging film may have gas barrier properties, light shielding properties, and the like. In particular, it is preferable to use a PET film as the synthetic resin film because it is excellent in bonding stability at the time of lamination, printability, and the like. When the packaging film is a laminated film, it is preferable to use a PET film as the outer layer. Moreover, in order to make it heat-sealable, when a packaging film is formed in a bag shape, what has a sealant layer is preferable. The thickness of the packaging film is, for example, about 30 to 300 μm.

  The lid label 2 is releasably and releasably attached to the upper surface of the packaging bag 1 and covers the outlet 10 in an openable and closable manner. The shape of the lid label 2 only needs to be able to cover the outlet 10 and is therefore larger than the outlet 10. Since the takeout port 10 has a long shape along the long side of the upper surface of the packaging bag 1 having a substantially rectangular shape in plan view, the lid label 2 is also long along the long side of the upper surface of the packaging bag 1. And the longitudinal direction is taken as the peeling direction (opening direction). The direction of arrow A in FIG. 2 is the peeling direction. The peeling direction substantially coincides with the longitudinal direction of the lid label 2, and one end side of the lid label 2 which is the left side in the drawing is the beginning end side of the peeling direction, and the lid label 2 which is the right side in the same direction. The other end side is the end side in the peeling direction.

  The lid label 2 is provided with an opening / closing portion 20 which is peeled off from the packaging bag 1 with one end side as the start end side and the other end side as the end side, and a support portion 21 for supporting the opening / closing portion 20 ing. In FIG. 2 and the like, a boundary line is virtually drawn between the opening / closing portion 20 and the support portion 21 by a two-dot chain line. In the present embodiment, the opening / closing portion 20 is positioned at one end side of the lid label 2 and the support portion 21 is positioned at the other end side. Then, in the vicinity of the boundary between the opening / closing portion 20 and the support portion 21, a stopper cutting line 22 for stopping peeling of the lid label 2 is formed. That is, the stopper cutting line 22 is formed on the peeling end side (the other end side) of the lid label 2. The shape of the stopper cutting line 22 may be various, but for example, it may be U-shaped as shown in FIG. 1 etc., and a pair of lid labels 2 may be provided spaced apart in the width direction. it can. Further, at one end portion which is an end portion on the peeling start side of the lid label 2, a knob portion 23 which is not adhered to the packaging bag 1 is formed. The shape of the knob 23 is arbitrary, but can be semicircular as shown in FIG. However, the band-like region may be used as the picking portion 23 by forming a non-bonding region in a band shape over the entire width of the lid label 2 instead of forming the picking portion 23 in a semicircular or other projecting shape. . The term "non-adhesion" also includes weak adhesion which peels off with a very small force.

  The back surface of the lid label 2 is divided into an adhesive portion which can be peeled off and reattached to the packaging bag 1 and a non-adhesive portion which is not adhered to the packaging bag 1, and the back surface of the knob 23 is not adhered And the other part is the adhesive part. As described above, the non-adhered part includes the state of weak adhesion which peels off with a very small force.

  Here, the layer structure of the lid label 2 will be described. The lid label 2 includes a base film 30, an adhesive layer 31 laminated on the back surface of the base film 30, print layers 32 and 33 formed on the surface of the base film 30, and a base as shown in FIG. A protective film 35 laminated on the front side of the film 30 via a laminating layer 34 is provided.

  The base film 30 is composed of various flexible films, and in particular, various transparent plastic films are used. Examples of plastic films include ester resins such as polyethylene terephthalate and polylactic acid, olefin resins such as polypropylene, styrene resins such as styrene-butadiene copolymer, and thermoplastic resins such as cyclic olefin resins and vinyl chloride resins. It is preferable to use these biaxially stretched films from the viewpoint of being excellent in mechanical strength among them. In particular, it is preferable to use a biaxially oriented polyester film. The thickness of the base film 30 is also not particularly limited, and is, for example, 25 μm to 120 μm, preferably 30 μm to 100 μm. In the case of a polyethylene terephthalate film, the thickness is preferably 35 to 75 μm. In addition to the synthetic resin film, the base film 30 may be paper, nonwoven fabric, synthetic paper or the like.

  Design print layers 32 of various characters and designs are formed as print layers. The design print layer 32 is formed by applying various inks compatible with the printing method to the base film 30 by various printing methods, and curing. As shown in FIG. 3A, the design print layer 32 may be formed directly on the surface of the base film 30. In the case of using, for example, a transparent film as the base film 30, as shown in FIG. 3B. Alternatively, a solid print layer 33 such as a white solid print layer or a silver solid print layer may be formed on the surface of the base film 30, and the design print layer 32 may be further formed on the solid print layer 33. In the case of a design configuration in which the design of the packaging bag 1 is shown through the lid label 2, a transparent film is used for the base film 30, and design printing is performed only on the predetermined location of the base film 30 as shown in FIG. The layer 32 is formed. On the other hand, in the case of a design in which the lid label 2 has a design different from that of the packaging bag 1, a solid print layer 33 is formed on the surface of the base film 30 as a base layer as shown in FIG. A design print layer 32 is formed thereon. An ultraviolet curable ink etc. can be used as a printing layer.

  The laminate layer 34 is an adhesive layer which is laminated over the entire base film 30 so as to cover the print layer from the front side, and which integrally integrates the base film 30 and the protective film 35. The laminating layer 34 is formed by various laminating methods such as dry laminating and UV laminating. The laminate layer 34 is also transparent.

  The protective film 35 is for protecting the print layer from the front side, and a transparent film is used. For the film, the same transparent film as the base film 30 described above can be used. The protective film 35 and the laminate layer 34 may be omitted.

  The adhesive layer 31 is formed by applying an adhesive to the back surface of the base film 30. As the pressure-sensitive adhesive, an ultraviolet-curable hot-melt pressure-sensitive adhesive is used instead of a conventional solvent-based pressure-sensitive adhesive. Specifically, an ultraviolet-curable acrylic-type hot-melt pressure-sensitive adhesive is used. The thickness of the pressure-sensitive adhesive layer 31 is, for example, 10 to 30 μm. The pressure-sensitive adhesive has a gel fraction of 65 to 80% by weight. When the gel fraction is 65 to 80% by weight, excellent sealability (sealability of the outlet 10) and good peelability (openability) even after long-term storage can be ensured. If the gel fraction is less than 65% by weight, the adhesive strength after long-term storage becomes too large, and it becomes difficult to peel off smoothly, resulting in poor openability. On the other hand, if the gel fraction exceeds 80% by weight, the adhesive strength to the packaging bag 1 is reduced and the sealing property is inferior, and in particular, the initial adhesive strength immediately after adhering the lid label 2 to the packaging bag 1 is insufficient. Cheap.

<Definition of gel fraction>
Here, the gel fraction is defined as follows. The weight of the pressure-sensitive adhesive layer 31 wrapped by a 200 mesh wire mesh is measured, and this weight is taken as the weight before immersion. The adhesive layer 31 wrapped in a 200 mesh wire mesh is immersed in tetrahydrofuran for 24 hours and then subjected to ultrasonic irradiation for 1 hour, taken out of the tetrahydrofuran, dried and removed from the tetrahydrofuran, and the weight is measured. The weight is taken as the weight after immersion. And a gel fraction is calculated | required by the following formula.
Gel fraction (% by weight) = (weight after immersion−weight of wire mesh) / (weight before immersion−weight of wire mesh) × 100

  The gel fraction is also included in the ultraviolet curable acrylic hot melt adhesive depending on the composition, weight average molecular weight and content of the acrylic prepolymer which is the base polymer of the ultraviolet curable acrylic hot melt adhesive. It can be suitably adjusted by the type and content of the photopolymerization initiator, and by the light amount of the ultraviolet light (integrated light amount) and the like.

 The UV curable acrylic hot melt adhesive contains an acrylic prepolymer as a main component, and may be a hot melt adhesive that can be cured (crosslinked) by ultraviolet light, and is an acrylic prepolymer, a photopolymerization initiator, It is preferred to include a tackifier. When the tackifier is included, the initial adhesive strength is excellent.

  The adhesive layer 31 is formed on the entire back surface of the base film 30. The back surface of the lid label 2 for lid is bonded to a non-bonded portion by forming a masking layer also called so-called "glue killing" or "glue suppression" on a part of the entire back surface of the pressure-sensitive adhesive layer 31. And divided into That is, the adhesion strength of the portion where the masking layer is formed is smaller than that of the portion where the masking layer is not formed. Therefore, the portion of the back surface of the pressure-sensitive adhesive layer 31 where the masking layer is formed is a non-adhesion portion, and the portion of the back surface of the pressure-sensitive adhesive layer 31 where the masking layer is not formed remains an adhesion portion. The masking layer can be formed by a known printing method using a masking agent. The masking agent is preferably a non-adhesive layer that can be cured by ultraviolet light and can be formed on the pressure-sensitive adhesive layer 31, and an ultraviolet curable ink or the like can be used. However, instead of forming the adhesive layer 31 on the entire back surface of the base film 30, the adhesive layer 31 is formed only on the back surface of the base film 30 corresponding to the bonded portion, and the base film 30 corresponding to the non-bonded portion. The adhesive portion and the non-adhesive portion may be partitioned so as not to form the adhesive layer 31 on the back surface.

  Samples were prepared by changing various adhesives and evaluated. The evaluation results are shown in Table 1. In the table, "UV hot melt" is an ultraviolet curable acrylic hot melt pressure sensitive adhesive, and adhesive strength is to a PET film as a packaging material. In addition, “% change after storage” is a comparison of the adhesive strength after storage with the adhesive strength after 24 hours of room temperature (initial adhesive strength) ((adhesive strength after storage) − (room temperature 24 Adhesive strength after time) ÷ (adhesive strength after room temperature 24 hours). The larger the value of the “change rate after storage”, the larger the change with time of the adhesive strength, and conversely, the smaller the value of the “change rate after storage”, the smaller the change with time of the adhesive strength.

  The adhesive strength was measured by the method according to JIS Z 0237 as follows. A label piece is cut into a length of 25 mm and a length of 150 mm, and the non-corona treated side of a PET film (made by Toyobo Co., Ltd., biaxially stretched PET film: E5100) with a manual pressure bonding device (described in JIS Z 0237 10.2.4) I stuck it. After pasting, the adhesive strength is measured at a speed of 300 mm / min with Autograph AG-I 500N manufactured by Shimadzu Corporation after storage for 24 hours at normal temperature (room temperature, 23 ± 2 ° C., RH 60 ± 5%), and the unevenness average The test force was taken as the measured value. The adhesive strength after 24 hours of this room temperature is taken as the initial adhesive strength. In addition, storage for one month at 50 ° C. refers to storage for one month at 50 ° C. in a dry oven (FC410 manufactured by ADVANTEC Toyo Co., Ltd.) after being attached to a PET film as described above. After storage, after further storing at room temperature for 1 hour, the adhesive strength was measured in the same manner as described above.

  In the case of Examples 1 to 3 shown in Table 1, the sealability was also good, and the removability after long-term storage was also good. Further, in the case of Examples 1 to 3, the change rate after storage is 4 to 20%, and the change with time of the adhesive strength of the pressure-sensitive adhesive after long-term storage is small. On the other hand, in Comparative Example 1 in which a solvent-based pressure-sensitive adhesive was used, the adhesive strength after long-term storage became too large, the peelability deteriorated, and it was difficult to peel smoothly. Further, in Comparative Example 2, even if it is the same UV curable acrylic hot melt adhesive as in Examples 1 to 3, the gel fraction is as low as 62.3% by weight, so the adhesive strength after long-term storage becomes large. It was too easy to obtain a favorable peelability and to peel smoothly. Among Examples 1 to 3, the one having the largest gel fraction is 76.3% by weight of Example 3, but the larger the gel fraction, the smaller the initial adhesive strength. Therefore, if the gel fraction becomes too large, the initial adhesive strength becomes too small, which causes problems in sealing property. Thus, by adjusting the gel fraction to 65 to 80% by weight, both the sealing property and the releasability can be achieved. Moreover, as for the adhesive strength after storing for 1 month at 50 degreeC, it is preferable that it is 1.0-4.0 N / 25 mm from a viewpoint of making sealing property and releasability make compatible. When the initial adhesive strength is less than 0.5 N / 25 mm, the initial adhesive strength is insufficient and a problem occurs in the sealing property. Therefore, the initial adhesive strength needs to be at least 0.5 N / 25 mm. Conversely, if the initial adhesive strength is too high, the removability after storage becomes a problem, and the initial adhesive strength is preferably 3.5 N / 25 mm or less. Therefore, the initial adhesive strength is preferably 0.5 to 3.5 N / 25 mm, particularly 1.0 to 3.2 N / 25 mm, and more preferably 1.5 to 3.0 N / 25 mm It is. Moreover, it is preferable that a change rate after storage is 25% or less.

  In the above embodiment, although the case where the packaging material is the packaging bag 1 in which the flexible film is formed in a bag shape has been described, the present invention is not limited thereto, for example, an assembly box of paper or synthetic resin sheet or synthetic resin The container may be a molded container, a glass container, a metal container or the like, and the type and material of the packaging material are also optional.

DESCRIPTION OF SYMBOLS 1 packaging bag 2 label 10 lid lid 20 opening part 21 opening / closing part 21 support part 22 cut line for stopper 23 picking part 30 base film 31 adhesive layer 32 design printing layer 33 solid printing layer 34 laminating layer 35 protective film A peeling direction

Claims (3)

A lid label that is releasably and releasably affixed to a packaging material so as to cover a takeout opening for taking out the package.
The adhesive on the back side is a UV curable hot melt adhesive, and its gel fraction is 67 to 77 % by weight,
Adhesive strength to the packaging material after storage for 24 hours at room temperature is 0.5 to 3.5 N / 25 mm,
Adhesive strength to the packaging material after one month storage at 50 ° C is 1.0 to 4.0 N / 25 mm,
The adhesive strength to the packaging material after storage for 24 hours at room temperature is taken as the adhesive strength after 24 hours at room temperature, and the adhesive strength to the packaging material after storage for 1 month at 50 ° C is taken as the adhesive strength after storage,
Assuming that ((adhesive strength after storage)-(adhesive strength after room temperature 24 hours)) ÷ (adhesive strength after room temperature 24 hours) is a change rate after storage, the change rate after storage is 25% or less Characteristic label for lid. The lid label according to claim 1 , wherein the adhesive strength after 24 hours of room temperature is 1.5 to 3.0 N / 25 mm . A package comprising the lid label according to claim 1 or 2 .

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