JP5202199B2 - Heat shrinkable labels and containers - Google Patents

Description

  The present invention relates generally to heat-shrinkable labels, and more particularly to a heat-shrinkable label that is improved so that it can be easily peeled from a container. The present invention also relates to a container having such a heat-shrinkable label mounted on the outer periphery of the body.

  A heat-shrinkable label that is adhered to the entire circumference of a plastic bottle and other glass bottles and the body of a plastic bottle by heat-shrink force is widely used. A PET bottle or the like in which the heat-shrinkable label is wound around a container is widely distributed as a container filled with water, juice or the like.

  On the other hand, in recent years, with the increasing protection of the global environment, heat-shrinkable labels are also available for containers such as plastic bottles wrapped with heat-shrinkable labels so that they can easily be sorted into different types of waste when disposed of after use. It is required that it can be easily separated from the container.

  As a method for satisfying this requirement, heat-shrinkable labels with perforations are widely known. As another method, Patent Document 1 discloses a cylindrical film 2 having an overlapping portion 1 in which both end portions in a shrinking direction of one heat shrinkable film are overlapped and joined as shown in FIG. Disclose. An unbonded portion 3 is formed on a part of the overlapping portion 1. As shown in FIG. 8, this is attached to the outer peripheral surface of the container 4 such as a glass bottle or a plastic bottle, and is thermally contracted to adhere to the container.

  Referring to FIG. 7, the overlapping portion 1 is formed on the back surface of one end edge in the shrinking direction of the heat-shrinkable film, a solvent having moderate solubility in the heat-shrinkable film, for example, a cyclic ether type such as tetrahydrofuran. A solvent is applied, and the solvent-coated portion of the heat-shrinkable film is welded so as to overlap with the other edge to which the other solvent is not applied.

The container 4 with the heat-shrinkable label in close contact has the unjoined portion 3 in the overlapping portion of the heat-shrinkable label. By pulling with the tip, the heat-shrinkable label is separated from the container.
JP 2004-212758 A

  From the viewpoint of environmental problems and costs, plastic bottles for beverages are becoming thinner and less strong due to the reduced amount of resin used. When a conventional heat-shrinkable label with perforations is attached to such a plastic bottle, for example, if the plastic bottle is accidentally dropped, the plastic bottle is deformed by the impact of the drop, and the heat-shrinkable The label may not be able to absorb the deformation and may break from the perforation. Furthermore, in the configuration of Patent Document 1, there is a problem that when the heat shrinkage is performed, the unjoined portion is shrunk, and the appearance is poor and easily caught.

  The present invention has been made in view of such problems, and provides a heat-shrinkable label that can be easily separated from an attached container and that is not torn by a drop impact or the like. With the goal.

  Another object of the present invention is to provide a container equipped with such a heat-shrinkable label.

The present invention relates to a heat-shrinkable label that is formed into a cylindrical shape by overlapping and joining one end and the other end of a heat-shrinkable film that is a base material, and is attached to the outer periphery of a body of a container. Related. The overlapping portion includes a strong adhesion portion and a non-adhesion portion or a weak adhesion portion provided above and / or one of the strong adhesion portions. The unadhered portion or the weakly bonded portion is bonded with a heat-shrinkable film serving as a base material sandwiching an adhesion adjusting layer. A shrinkage suppression layer is provided on the surface of the unbonded portion or the weakly bonded portion on the side that does not contact the container. The adhesion adjusting layer and the shrinkage suppression layer are formed of an acrylic resin, a urethane resin, or a mixture thereof.

  A perforation may be provided in parallel to the overlapping portion.

  A cut may be provided instead of the perforation next to the unbonded portion or the weakly bonded portion.

  The present invention also relates to a container equipped with a heat-shrinkable label having the above characteristics.

  According to the present invention, since the shrinkage adjustment layer is provided on the non-contact surface side of the non-bonded portion or the weakly bonded portion with the container, the appearance is not caused by warping due to the shrinkage at the time of heat shrinkage. Excellent. Further, the label can be easily peeled off from the container by pulling the tip of the non-bonded portion or the weakly bonded portion.

  For the purpose of obtaining a heat-shrinkable label improved so that it can be easily peeled off, the overlapped portion is made of a strongly bonded portion, and an unbonded portion or a weak portion provided above and / or one of the strongly bonded portion. It was realized by constituting with an adhesive part, and appearance defects such as warpage of the non-adhered part or weakly adhesive part due to thermal shrinkage were prevented by forming a shrinkage suppression layer. Hereinafter, details of the present invention will be described with reference to the accompanying drawings.

  The base film is not particularly limited as long as it has heat shrinkability. Polystyrene heat-shrinkable films (“GMV type”, “GMG type” manufactured by Gunze Co., Ltd., etc.), polyester heat-shrinkable films (Toyobo Co., Ltd. Registered trademark) “S7053”, etc.) or a composite heat-shrinkable film (“HGT type” manufactured by Gunze Co., Ltd.) can be suitably used.

  The adhesion adjusting layer is formed from an acrylic resin, a urethane resin, or a mixture thereof. The acrylic resin is a polymer of (meth) acrylic acid and its derivatives. The urethane resin is a polymer of polyester or polyether and isocyanate.

  The shrinkage suppression layer is formed from an acrylic resin, a urethane resin, or a mixture thereof. The acrylic resin is a polymer of (meth) acrylic acid and its derivatives. The urethane resin is a polymer of polyester or polyether and isocyanate.

  A lubricant and a particulate matter may be added to the adhesion adjusting layer and the shrinkage suppression layer as necessary.

  Examples of the lubricant include synthetic waxes such as polyethylene wax, paraffin or ethylene-acrylic acid copolymer wax, and natural waxes such as petroleum jelly, lacquer wax or carnauba wax.

  Examples of the particulate matter include inorganic particles such as silica, talc, mica, and titanium oxide, and organic particles such as polymethacrylate and polystyrene.

  The thickness of the adhesion adjusting layer is preferably 0.2 μm to 2.0 μm, more preferably 0.5 μm to 1.0 μm. When the thickness is about this level, the adhesion adjusting layer wetted by the center seal solvent acts in the same manner as the adhesive, and the strength is weak even if the adhesive force is developed.

  The thickness of the shrinkage suppression layer is preferably 0.2 μm to 3.0 μm, more preferably 0.5 to 2.0 μm. A thickness of this level is preferable because the base film can be effectively prevented from shrinking.

  The adhesion adjusting layer and the shrinkage suppressing layer are prepared as a printing ink composition based on the resin, and are formed on the base film by a generally known printing method such as a gravure printing method. The printing ink composition may be a colorless ink containing no pigment or a design ink containing a pigment.

  The adhesive strength of the strong adhesive part of the heat-shrinkable label of the present invention is preferably 3 to 6 N / 10 mm. As shown in FIG. 1, the adhesive strength is the strength (180 degree peeling) when pulled in the direction indicated by the arrow. In FIG. 1, 5 is a label, and 6 is an adhesive layer.

  If the adhesive strength is less than 3 N / 10 mm, the overlapped portion may be peeled off when the heat-shrinkable label is attached, or the overlapped portion may be peeled off when transported. On the other hand, if it exceeds 6 N / 10 mm, the overlapped portion will not be peeled off easily even if the unbonded portion or weakly bonded portion is pinched with a finger and pulled, such being undesirable.

  The adhesive strength is adjusted by the difference between the solubility parameter (SP value) of the base film and the solubility parameter (SP value) of the sealing solvent.

  When the SP value of the base film is close to the SP value of the sealing solvent, the base film is easily eroded and easily swelled or dissolved, and can be sealed more firmly. A sealing solvent having a large difference from the SP value of the base film is difficult to seal because it does not swell or dissolve. Adhesion strength can be adjusted by mixing such two types of solvents, that is, a solvent having an SP value having a small difference from the SP value of the base film and a solvent having an SP value having a large difference. That is, if the ratio of the solvent having a small SP value increases, the adhesive strength increases, and if the ratio of the solvent having a large SP value difference increases, the adhesive strength decreases.

  The adhesion strength of the unadhered part or the weakly adhered part is adjusted by the adhesion adjusting layer so as to be 1.5 N / 10 mm or less. Such adjustment is made mainly by the amount of resin to be printed and applied. Specifically, it is adjusted by the number of lines of the gravure plate, the plate depth, and the viscosity of the printing ink composition.

  An adhesive strength of 1.5 N / 10 mm or less is preferable because it can be easily peeled off and easily pinched with a finger.

  2A is a perspective view of the heat-shrinkable label according to Example 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. 3A is a development view of the heat-shrinkable label according to Example 1, and FIG. 3B is a cross-sectional view taken along line BB in FIG. 3A.

  With reference to these drawings, the heat-shrinkable label according to Example 1 is formed into a cylindrical shape by overlapping and joining one end and the other end of the heat-shrinkable base film 7. It is attached to the outer periphery of the body of the container. A pattern print 12 is formed on the back surface of the base film 7. The overlapping portion includes a strong adhesion portion 8 and a weak adhesion portion 9 provided above and below the strong adhesion portion 8. In the weakly bonded portion 9, the base film 7 is bonded with the adhesion adjusting layer 10 interposed therebetween. A shrinkage suppression layer 11 is provided on the surface of the weakly bonded portion 9 that does not contact the container. In the figure, the shrinkage suppression layer 11 is written with a considerable thickness for the convenience of drawing, but this drawing is not drawn to scale. As described above, the thickness of the shrinkage suppression layer 11 is preferably 0.2 μm to 3.0 μm, more preferably 0.5 to 2.0 μm.

  As the base film 7, “GMV” type 50 μm manufactured by Gunze Co., Ltd. was used. On the back surface of the base film 7, necessary patterns, letters, etc. are provided by gravure printing using “OS-M” ink manufactured by Dainichi Seika Kogyo Co., Ltd. The adhesion adjustment layer 10 and the shrinkage suppression layer 11 were provided by gravure printing on the surface (surface). The adhesion adjustment layer 10 uses “fine wrap scratch prevention medium” (acrylic resin base) manufactured by DIC Corporation, and the shrinkage suppression layer “OS-M” manufactured by Dainichi Seika Kogyo Co., Ltd., which is similar to pattern printing. (Acrylic resin base) was used. The printing conditions were a drying temperature of 40 ° C. to 60 ° C. and a printing speed of 80 m / min to 150 m / min.

As the gravure plate for pattern printing, laser plate making, 175 lines, and plate depth of 26 μm were used.
The gravure plate for forming the adhesion adjusting layer 10 and the shrinkage suppression layer 11 is a laser plate making and has a plate depth of 12 μm to 26 μm. The ink viscosity was 17.0 seconds (Zahn Cup # 3).

  Next, a solvent having moderate solubility in the base film 7, for example, an organic solvent such as cyclohexane, n-hexane, and ethyl acetate is applied to the back surface of one end in the shrinking direction of the base film 7. Then, the solvent-coated portion of the base film 2 was overlapped with the other edge to which the other solvent was not applied to form a strong adhesion portion 8, which was processed into a cylindrical shape and wound up.

  As shown in FIG. 2B, the heat-shrinkable label is bonded with the adhesion adjusting layer 10 interposed therebetween so that the shrinkage adjusting layer 11 is on the outer surface (non-contact surface with the PET bottle) side of the heat-shrinkable label. manufactured.

  Next, the heat-shrinkable label that has been completed is cut into a length equivalent to one plastic bottle, covered with a plastic bottle, and heated using a steam tunnel (“SH5000” manufactured by FUJIA STEC Co., Ltd.) at a heating temperature of 85 to 95 ° C., Shrinkage was applied with a passage time of 7 seconds.

  The appearance of the PET bottle to which the heat-shrinkable label was attached was such that the weak joint was slightly shrunk and floated by heat shrinkage, and it was easy to pinch without warping and was good.

  Since the PET bottle with the heat-shrinkable label has the weak adhesive portion 9 in the overlapping portion of the heat-shrinkable label, the joint portion is formed by holding the tip of the weak adhesive portion 9 and pulling along the joint portion. The heat-shrinkable label was easily separated from the PET bottle.

  4 is a perspective view of a heat-shrinkable label according to Example 2. FIG. The heat-shrinkable label and the heat-shrinkable label were the same as in Example 1 except that one perforation 13 was inserted along the joint in the longitudinal direction of the heat-shrinkable label (perpendicular to the main shrinkage direction). Obtained a plastic bottle. The ratio of the perforated cut part to the non-cut part was 0.4 (cut part) /3.0 (non-cut part). The heat-shrinkable label was easily separated from the PET bottle.

  FIG. 5 is a perspective view of the heat-shrinkable label according to Example 3. The heat-shrinkable label and the heat-shrinkable label are the same as in Example 1 except that a cut 14 for facilitating peeling is provided instead of the perforated line next to the weakly bonded portion 9 of the heat-shrinkable label. An attached plastic bottle was obtained. The heat-shrinkable label was easily separated from the PET bottle.

The cut 14 was formed by cutting with laser processing (CO2 laser marker ML-Z9500 manufactured by Keyence Corporation). The length of the cut 30 is preferably in the range of 0.5 to 3 mm from the top of the label. If it is 3 mm or more, the curl at the time of contraction becomes large, and if it is 0.5 mm or less, the weakly bonded portion 9 is difficult to cut. The position of the notch 14 is preferably in the range of 3 to 15 mm from the weakly bonded portion 9. If it is 3 mm or less, it is difficult to grasp the knob of the weakly bonded portion 9, and if it is 15 mm or more, the force when grasping and pulling the knob of the weakly bonded portion 9 is difficult to be transmitted to the notch 14. The part is hard to cut downward.
(Comparative Example 1)

  A PET bottle equipped with a heat-shrinkable label and a heat-shrinkable label was obtained in the same manner as in Example 1 except that no shrinkage suppression layer was provided.

Table 1 shows the results of Examples 1-3 and Comparative Examples.

  (Evaluation method)

[Shrinkability]
Cover the PET bottle with a heat-shrinkable label, and use a steam tunnel ("SH5000" manufactured by FUJIA STEC Co., Ltd.) to heat and shrink it at a heating temperature of 85 to 95 ° C and a passing time of 7 seconds. Evaluation was based on the presence or absence of curling up and warping. A state where there was no turning up or warping was indicated as “◯”, and a case where turning up or warping occurred was indicated as “X”.

[Label peel strength]
A method for measuring the label peeling strength will be described. A cylindrical heat-shrinkable label as shown in FIG. 6 (A) was prepared. Here, the one in which the shrinkage suppression layer 11 is formed only on the upper side of the strong adhesion portion is used. With reference to FIG. 6B, a width of 20 mm was cut out centering on the overlapped portion. FIG. 6C is a cross-sectional view taken along line CC in FIG. Referring to FIG. 6C, the weak adhesive portion is peeled off at one end and the other end of the weak adhesive portion of the overlapped portion, and the chuck is gripped using a polyester adhesive tape “No31E 35 High” manufactured by Nitto Denko Corporation. The margin 20 was created, and was measured at a speed of 200 mm / min by pulling in the direction of the arrow (180 degree peeling) using an autograph “AGS-100A” manufactured by Shimadzu Corporation.

  In Example 1-3 described above, the case where the weakly bonded portions are formed above and below the strongly bonded portion is exemplified. However, even if the weakly bonded portions are provided only on one side, there are considerable effects.

  In the above embodiment, the mode of forming the weakly bonded portion is illustrated by providing the adhesion adjusting layer. However, such an adhesion adjusting layer is not provided, but a peeling varnish is provided instead to become an unbonded portion. It may be.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, since the heat-shrinkable label can be easily peeled off from the PET bottle, the PET bottle can be efficiently recycled.

It is a figure which shows how to obtain | require adhesive strength. (A) It is a perspective view of the heat-shrinkable label concerning Example 1. FIG. (B) It is sectional drawing which follows the BB line in FIG. 2 (A). (A) It is an expanded view of the heat-shrinkable label concerning Example 1. FIG. (B) It is sectional drawing which follows the BB line in FIG. 3 (A). It is a perspective view of the heat-shrinkable label concerning Example 2. FIG. It is a perspective view of the heat-shrinkable label concerning Example 3. FIG. It is a figure for demonstrating the measuring method of label peeling strength. It is a perspective view of the conventional heat-shrinkable label. It is a figure which shows the use condition which mounted | wore the container with the conventional heat-shrinkable label.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superposition part 2 Film 3 Non-adhesion part 4 Container 5 Label 6 Adhesive layer 7 Base film 8 Strong adhesion part 9 Weak adhesion part 10 Adhesion adjustment layer 11 Shrinkage suppression layer 13 Perforation 14 Notch 20 Grab

Claims (4)

A heat-shrinkable label that is formed into a cylindrical shape by overlapping and joining one end and the other end of a heat-shrinkable film that is a base material,
The overlapping portion includes a strong adhesion portion, and an unadhered portion or a weak adhesion portion provided above or below or one of the strong adhesion portions,
The unbonded part or the weakly bonded part is bonded with a heat shrinkable film as a base material sandwiching an adhesion adjusting layer,
A shrinkage suppression layer is provided on the surface of the non-bonded portion or the weakly bonded portion on the side that does not contact the container ,
The heat-shrinkable label in which the adhesion adjusting layer and the shrinkage suppression layer are formed from an acrylic resin, a urethane resin, or a mixture thereof . The heat-shrinkable label according to claim 1, wherein a perforation is provided in parallel with the overlapping portion. The heat-shrinkable label according to claim 1 , wherein a notch is provided next to the unbonded portion or the weakly bonded portion. A container equipped with the heat-shrinkable label according to any one of claims 1 to 3 .