JP2011013395A - Label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label that can be easily peeled off from a plastic container without being peeled off when being peeled off from the plastic container after being stuck on the plastic container without being peeled off during storage or transportation. That is.
A label attached to a plastic container has a structure in which a paper substrate and a heat-sensitive adhesive layer are laminated via a release layer, and the surface of the heat-sensitive adhesive layer is bonded to the surface of the plastic container and at least the paper The substrate is formed to be peelable from the plastic container.
[Selection] Figure 1

Description

  The present invention relates to a label based on paper affixed to the surface of a plastic container or the like.

  Conventionally, a printed label is attached to the surface of a container such as plastic, glass, or can as a method for appealing the contents of a product to consumers. As the material of the label, papers, various plastic films, or a structure in which these are laminated are used in a wide variety. In recent years, with the aim of building a recycling-oriented society, the Containers and Packaging Recycling Law has been enacted, and after consuming the contents filled in the containers, consumers dispose of the packaging containers according to the separate collection standards set by the municipality. It is requested that. At the time of separation, the label attached to the surface of the container or the attached label needs to be peeled off and separated from the surface of the container. For example, in the case of a shrink label, it is possible to cut and peel off a part of the label because the label is attached to the container. However, in the case of a label based on paper, the surface of the container and the label pass through an adhesive layer. Therefore, there is a problem that it is difficult to separate the label from the container because the paper substrate is torn when it is peeled off.

  As a solution to the above problem, an in-mold in which paper is used for the label base material and a printed layer is provided on the front surface, and a release layer is provided on the back surface that has appropriate adhesiveness with the plastic container. A label is disclosed (for example, see Patent Document 1). However, in the in-mold label, the peelability from the plastic container is controlled by adjusting the adhesiveness of the peelable layer. Therefore, the peelable layer (heat-sensitive adhesive layer) is formed on the label side and the plastic container side by cohesive failure of the peelable layer. There is a problem that both may remain. Also, the adhesiveness varies depending on the adhesive conditions (temperature, time, pressure) that adjust the adhesiveness of the release layer, making it difficult to control the adhesiveness. For example, if the adhesive time is lengthened, the production capacity decreases or the production Each time the condition is changed, there arises a problem that the peelability of the label is changed, it is difficult to ensure stable adhesiveness, and it is difficult to satisfy both conflicting properties of the peelability and adhesiveness of the label.

  In addition, a paper label made of a laminated material in which a paper peeling prevention layer and a heat-sensitive adhesive layer are laminated on one surface of a paper base material layer is disclosed (for example, see Patent Document 2). This paper label uses a non-woven fabric or resin film that has a tensile strength higher than the interlayer strength of the base material layer made of paper as the paper peeling prevention layer, so paper peeling can be prevented, but the material cost of the paper peeling prevention layer is low. It will be expensive. Also, depending on the type of heat-sensitive adhesive layer, the paper will not peel off, but the peel strength from the plastic container will be strong and it will not be easily peeled off. There is a problem that may remain.

JP 2004-256165 A JP 2007-140118 A

  In view of the conventional problems as described above, the present invention is not peeled off during storage or transportation after being affixed to a plastic container, and is not peeled off when being peeled off from the plastic container. It is to provide a label that is more easily peelable than a plastic container.

  The label according to claim 1 of the present invention is a label affixed to a plastic container, wherein a paper substrate and a heat-sensitive adhesive layer are laminated via a release layer, and the surface of the heat-sensitive adhesive layer is on the surface of the plastic container. In addition to being bonded, at least the paper substrate is formed so as to be peelable from the plastic container.

  The present invention according to claim 2 is characterized in that, in the label according to claim 1, the label is peeled between the release layer and the heat-sensitive adhesive layer when the label is peeled from the plastic container. It is what.

  The label of the present invention is a label affixed to a plastic container, wherein the paper base and the heat-sensitive adhesive layer are laminated via the release layer, so that the heat-sensitive adhesive of the heat-sensitive adhesive layer is the paper-based adhesive. In order to prevent the material from being impregnated, the label can be easily peeled without tearing the paper when the label is peeled from the plastic container when the plastic container is discarded. In particular, when a label is applied by in-mold molding, the heat-sensitive adhesive of the heat-sensitive adhesive layer thermally melted by the release layer is not impregnated into the paper substrate, so that the appropriate range of molding conditions for the plastic container is widened. The productivity of the in-mold label container can be improved by increasing the temperature and shortening the molding time.

  In addition, the label of the present invention is configured to peel between the release layer and the heat-sensitive adhesive layer, whereby the heat-sensitive adhesive layer and the plastic container can be strongly bonded, and the adhesive force between the release layer and the heat-sensitive adhesive layer. By controlling the thickness, it can be easily peeled between the peeling layer and the heat-sensitive adhesive layer, and can be separated into a label and a plastic container. Furthermore, the peeled label is only the paper substrate and the release layer, while the heat-sensitive adhesive layer is transferred to the plastic container side, and can be separated into paper and plastic and easily discarded.

It is a top view which shows one Embodiment of the label which concerns on this invention. FIG. 2 is a cross-sectional view taken along line YY in FIG. 1. It is a vertical side view which shows an example which stuck the label which concerns on this invention to the plastic container.

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view showing an embodiment of a label according to the present invention, FIG. 2 is a sectional view taken along line YY in FIG. 1, and FIG. 3 is a longitudinal side view showing an example in which the label according to the present invention is attached to a plastic container. FIG.
In the figure, reference numeral 1 is a label, 2 is a printed layer, 3 is a paper substrate, 4 is a release layer, 5 is a heat-sensitive adhesive layer, 6 is a plastic container, 7 is a flange, 8 is an outer peripheral side surface of the container body, and 10 is a label. Each attached container is shown.

  One embodiment of the label according to the present invention is as shown in FIGS. The label 1 of the present invention includes a printed layer 2 having a substantially fan-shaped planar shape and displaying information such as a product name, a brand name, and contents on the surface. As shown in FIG. 2, the label 1 has a configuration in which a printed layer 2, a paper base 3, a release layer 4, and a heat-sensitive adhesive layer 5 are sequentially laminated from the front surface, and the heat-sensitive adhesive layer 5 surface on the back surface is a plastic container. 6 (see FIG. 3).

Next, the label 1 of the present invention will be described in detail with reference to FIG. As the paper substrate 3, high-quality paper, art paper, coated paper, craft paper, pure white, imitation paper, or the like, or vapor-deposited paper obtained by evaporating aluminum on these papers can be used. The basis weight is preferably about 50 to 200 g / m ² . If the basis weight is less than 50 g / m ² , the label becomes weak, and when adhered to a plastic container, the label may wrinkle or tear. Also, if it exceeds 200 g / m ² , the paper becomes too stiff and the label has a strong repulsive force on the curved surface of the plastic container. The plastic container may be peeled off during transportation or storage.

  The printing layer 2 on the surface is provided by a printing method such as gravure printing, flexographic printing, or offset printing. On the surface of the printing layer 2, for example, a top coat layer is provided on the entire surface or a part thereof in order to impart properties that improve surface properties such as friction resistance and water resistance, and label suitability such as slipping and antistatic properties. Also good.

  The release layer 4 is provided for the purpose of preventing the heat-sensitive adhesive that forms the heat-sensitive adhesive layer 5 from impregnating the paper base material 3, and is an important role of the present invention. It is what has. That is, by providing the release layer 4, it is possible to prevent the paper substrate 3 from being impregnated with the heat-sensitive adhesive even when the heat-sensitive adhesive is applied thereon. Further, when the label 1 is thermally bonded to the plastic container. Even if the heat-sensitive adhesive forming the heat-sensitive adhesive layer 5 is melted by heat, the paper base 3 can be prevented from being impregnated, so that the adhesive force with the plastic container 6 (see FIG. 3) is stabilized. When the plastic container 6 is discarded, the label 1 can be peeled from the plastic container 6 without tearing the paper when the attached label 1 is peeled from the plastic container 6. The release layer 4 is dissolved or dispersed in a solvent, water, or an alcohol medium with one or a mixture of two or more synthetic resins such as acrylic, nitrified cotton, polyamide, cyclized rubber, chlorinated rubber, urethane, and poval. It is possible to perform coating by a coating method such as gravure coating, roll coating, etc., using the prepared product as a release agent. In addition, when providing the printing layer 2 on the surface, it is preferable because the printing layer 2 can be simultaneously provided on the surface of the paper base 3 using the gravure printing machine capable of double-sided printing, and this method is preferable. According to the method, it is possible not only to reduce the number of processes and to be advantageous in terms of cost, but also to shorten the delivery time. In order to control the adhesiveness with the heat-sensitive adhesive layer, silicone, wax or the like can be added to the release agent.

  For the heat-sensitive adhesive layer 5, a heat-sensitive adhesive that can be thermally bonded to the plastic container 6 is used. As the heat-sensitive adhesive, for example, acrylic resins, polyolefin resins, ethylene / vinyl acetate copolymer systems, polystyrene resins, polyester resins, polyamide resins and the like can be used, and may be appropriately selected depending on the resin of the plastic container 6. . The heat-sensitive adhesive can be applied by a coating method such as gravure coating or roll coating as a solution in which these resins are dissolved in an organic solvent, water, an emulsion in which alcohol is dispersed, or a suspension. In addition, polyolefin-based and ethylene / vinyl acetate copolymer-based resins may be provided by hot-melt extrusion using an extrusion method. Furthermore, it can be applied by a coating method such as gravure coating, roll coating or fountain coating as a hot melt agent obtained by mixing the above resin with tackifier, wax and the like.

  The label 1 of the present invention can be configured to peel between the release layer 4 and the heat-sensitive adhesive layer 5 when the label 1 is peeled from the plastic container 6. With this configuration, the heat-sensitive adhesive layer 5 and the plastic container 6 can be strongly bonded, and by controlling the adhesive force between the release layer 4 and the heat-sensitive adhesive layer 5, the label 1 can be peeled without tearing the paper. It can be easily peeled between the layer 4 and the heat-sensitive adhesive layer 5. Further, the peeled label is only the paper base material 3 and the release layer 4, while the heat-sensitive adhesive layer 5 is transferred to the plastic container 6 side, which can be separated into paper and plastic and easily discarded. More specifically, when the interlayer strength (a) of the paper substrate 3, the adhesive strength (b) between the release layer 4 and the heat-sensitive adhesive layer 5, and the adhesive strength (c) between the heat-sensitive adhesive layer 5 and the plastic container 6, A resin for forming the release layer 4 and the heat-sensitive adhesive layer 5 may be selected so as to satisfy the relationship of b <a and c. As an example, when the resin of the plastic container is polystyrene, an acrylic resin may be used for the release layer, and an ethylene / vinyl acetate copolymer resin may be used for the heat-sensitive adhesive layer. In addition, as another method for controlling the adhesive force between the release layer 4 and the heat-sensitive adhesive layer 5, the release layer 4 is usually formed by coating the release agent with all solids. A method of arbitrarily changing the coating area of the release agent within a range satisfying the relationship of b <a, c by changing the size, density, etc. of the halftone dots may be employed. In this case, the coating area of the release agent is preferably 70% or more. When the coating area is less than 70%, depending on the type of the paper base material or the heat-sensitive adhesive, there is a possibility that paper peeling may occur when the label is peeled from the plastic container.

  For the plastic container 6, a resin such as polyethylene, polypropylene, polystyrene, or polyester is used. A plastic container is manufactured by vacuum forming, pressure forming, or vacuum / pressure forming using a sheet made of these resins. Alternatively, these resins are used for blow molding or injection molding. The label 1 of the present invention may be attached by thermally bonding the label 1 to the plastic container 6 after the plastic container 6 is produced. In particular, when the plastic container 6 is molded, the label 1 is placed in the molding die. The label 1 and the plastic container 6 can be bonded at the same time as molding and used as an in-mold label.

Next, with reference to FIG. 3, an in-mold labeling method by vacuum / pressure forming of a plastic sheet will be described in the order of steps as an example of a manufacturing method of the labeled container 10 in which the label 1 of the present invention is attached to the plastic container 6. .
1) A single-wafer label or a take-up label punched into a predetermined shape is punched into a predetermined shape, and the label 1 is supplied.
2) Insert the supplied label 1 into a thermoforming mold (not shown) with the printed layer 2 side facing the thermoforming mold side and the heat-sensitive adhesive layer 5 side facing the plastic sheet.
3) The label 1 is held at a predetermined position in the mold by means of, for example, vacuum pressure from a plurality of holes provided in the mold.
4) A preheated plastic sheet is formed in a mold by vacuum and pressure forming to form a plastic container 6 having a flange 7 extending outwardly along the upper peripheral edge of the container body. At the same time, the label 1 is placed on the outer peripheral side surface of the container body. Affix to the surface of 8. In addition, the shape of the plastic container 6 illustrated the cup shape of the inverted truncated cone which expands upwards. Therefore, the fan-shaped label 1 can be attached along the outer peripheral side surface 8 of the container body.
5) After cooling, the labeled container 10 with the label 1 attached after trimming to a predetermined shape is taken out from the mold.
In addition, although the planar shape of the label 1 illustrated a fan shape and the plastic container 6 was a cup shape, the label of the present invention is not limited to this shape.

  Next, the present invention will be described in more detail with reference to the following examples.

A piece of art paper with a basis weight of 79.1 g / m ² is used as the paper base, and a printed layer is formed on the coated surface of the piece of art paper by a gravure printing method using a double-sided printing gravure printing machine, A solvent-type acrylic release agent was applied at a solid content of 1.5 g / m ² by a gravure printing method and dried to form a release layer. Next, a hot-melt coater was used to thermally melt an ethylene / vinyl acetate copolymer-based hot melt agent on the release layer and coat it at 10 g / m ² to provide a heat-sensitive adhesive layer. Then, the winding label was produced by slitting to a predetermined width. The interlayer strength (a) of the piece of art paper used was 5 N / 15 mm.

[Comparative Example 1]
A take-up label excluding the release layer of Example 1 was produced. Others were the same as in Example 1.

[Comparative Example 2]
A piece of art paper having a basis weight of 79.1 g / m ² was used as a paper substrate, and a printing layer was formed on the coated surface of the piece of art paper by a gravure printing machine by a gravure printing method. Thereafter, a gravure coater is used to apply a solid content of 5 g / m ² to a non-coated surface on the opposite side of the printed layer with 0.1% silicon wax added to nitrified cotton-based resin, and then dry to form a plastic container. A release resin layer having adhesiveness was formed. Then, the winding label was produced by slitting to a predetermined width.

[Comparative Example 3]
A piece of art paper having a basis weight of 79.1 g / m ² was used as a paper substrate, and a printing layer was formed on the coated surface of the piece of art paper by a gravure printing machine by a gravure printing method. Thereafter, a biaxially stretched polyethylene terephthalate film (PET) having a thickness of 12 μm was laminated by a dry lamination method on a non-coated surface on the opposite side of the printed layer with a dry laminator through a polyether-isocyanate adhesive. Further, an ethylene / vinyl acetate copolymer hot melt agent was thermally melted and coated at 10 g / m ² on a PET with a hot melt coater to provide a heat-sensitive adhesive layer. Then, the winding label was produced by slitting to a predetermined width.

  About Example 1 and Comparative Examples 1 to 3, after producing a container with a label by an in-mold labeling method by adhesion to a polystyrene (PS) sheet and vacuum / pressure forming of the PS sheet, the PS container and the label are peeled off. The sex was evaluated by the following method.

(Adhesiveness with PS sheet)
The produced winding label is cut into a strip of 60 mm × 100 mm, stacked so that the heat-sensitive adhesive layer surface of the label is in contact with a PS sheet having a thickness of 1.0 mm, and heat-pressed from the label surface with the heat sealer under the following conditions and heat sealed did. Thereafter, the adhesive strength between the label and the PS sheet was measured by a shopper type tensile test (tensile speed: 300 mm / min).
<Heat seal conditions>
Temperature: 80 ° C
Pressure: 2.0 kg / cm ²
Time: 1 second

(Peelability between PS container and label)
A labeled container prepared by adhering each take-up label and PS container under the following sheet molding conditions by an in-mold label method was used as a test sample.
Used PS sheet: Thickness 0.9mm
<Sheet forming conditions>
Mold temperature: 35-40 ° C
Molding time: 25 seconds
Preheating temperature: 140 ° C
The test sample was subjected to sensory evaluation on the feeling of peeling when the label was peeled from the container, whether the label was peeled off, and the peeled state. The evaluation criteria for the presence or absence of paper peeling were as follows.
<Evaluation criteria>
○ ・ ・ ・ No paper peeling.
× ・ ・ ・ There is paper peeling.
In addition, about the winding label of Example 1, the adhesive strength (b) of a peeling layer and a heat-sensitive adhesive layer was also measured.

  Table 1 shows the results.

As shown in Table 1, the label of Example 1 was easily peeled off from the PS container without peeling off the paper, and the peeled state was also good because it peeled cleanly between the peeled layer and the heat-sensitive adhesive layer.
Moreover, as shown in Table 1, the seal strength with the PS sheet of Example 1 was 1.0 N / 15 mm, and peeling was performed between the release layer and the heat-sensitive adhesive layer. That is, the adhesive strength (b) between the release layer and the heat-sensitive adhesive layer was 1.0 N / 15 mm. The seal strength with the PS sheet of Comparative Example 1 using the same heat-sensitive adhesive as in Example 1 is 5.5 N / 15 mm, and the adhesive strength (c) between the heat-sensitive adhesive layer and the PS container is 5.5 N / 15 mm. It shows that there is. The interlaminar strength (a) of the piece of art paper used is 5 N / 15 mm, and the relationship between the adhesive strength is
b <a, c
And it was as intended.
In Comparative Example 1, paper peeling occurred when the label was peeled off. In Comparative Examples 2 and 3, there was no paper peeling, but Comparative Example 2 caused cohesive failure of the release layer, making it difficult to completely separate the PS container and the paper, and the adhesion conditions (temperature, time, The adhesiveness fluctuates depending on the pressure), it is difficult to control the adhesiveness, and it is difficult to satisfy both conflicting properties of the peelability and adhesiveness of the label.
In Comparative Example 3, the heat-sensitive adhesive layer remains on both the paper side and the PS container side due to cohesive failure of the heat-sensitive adhesive layer, and it is difficult to completely separate, and the biaxially stretched polyethylene terephthalate film is used as a paper peeling prevention layer. As a result, the cost was high.

DESCRIPTION OF SYMBOLS 1 Label 2 Printed layer 3 Paper base material 4 Peeling layer 5 Heat-sensitive adhesive layer 6 Plastic container 7 Flange 8 Outer peripheral side surface of container body 10 Container with label

Claims (2)

The label attached to the plastic container has a structure in which a paper base material and a heat-sensitive adhesive layer are laminated via a release layer, and the heat-sensitive adhesive layer surface is adhered to the plastic container surface and at least the paper base material is A label formed so as to be peelable from a plastic container. The label according to claim 1, wherein the label is peeled between the release layer and the heat-sensitive adhesive layer when the label is peeled from the plastic container.

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