Adhesive-label-provided container and regeneration processing method of the same, and adhesive label for pasting onto polyethylene terephthalate container

Abstract

To provide an adhesive-label-provided container which is easily regenerated, a method of recycling the adhesive-label-provided container, and an adhesive label for pasting onto a polyethylene terephthalate container.SOLUTION: An adhesive-label-provided container 10 is obtained by pasting an adhesive label 12 onto a container 11, where the adhesive label 12 has a paper-containing support medium 21 and an adhesive layer 22 in this order, a specific gravity of the paper-containing support medium 21 is 1 or under, the adhesive layer 22 is composed of an adhesive, and the adhesive releases the adhesive label within 15 min. without remaining on a surface of the container 11 when immersing the adhesive-label-provided container 10 in a 2% alkali aqueous solution having a temperature of 70°C or higher and 90°C or lower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a container with an adhesive label, a method for recycling a container with an adhesive label, and an adhesive label to be affixed to a polyethylene terephthalate container. [Background technology]

[0002] Polyethylene terephthalate (hereinafter, sometimes referred to as PET) bottles are widely used as containers for drinking water, soft drinks, juice, tea, black tea, sake, shochu, etc. In recent years, there has been a significant increase in the demand for recycling PET bottles from the perspective of environmental protection. Many PET bottles have labels attached to them, such as shrink labels and glue labels, to indicate the product name and contents. In recent years, there have been an increasing number of cases where adhesive labels are used as display labels in order to reduce the area required. It is desirable for the display labels to be separated and disposed of before the PET bottles are collected, but the separation work is left to the purchaser, and in some cases the bottles are collected without the adhesive labels being removed. If the attached labels are not removed, it can cause an increase in steps in the recycling process, or can cause time and cost to be required, resulting in reduced processing efficiency. In recent years, therefore, there has been a demand for wash-off labels that can be easily removed during the washing process of PET containers.For example, Patent Document 1 discloses a removable adhesive sheet that uses a water-dispersible adhesive composition as an adhesive and a paper substrate as a substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-62416 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if the adhesive label can be removed from the PET bottle during the washing process, the paper base material sinks in water, making it difficult to separate it from the PET. The present invention has been made in consideration of the above circumstances, and aims to provide a container with an adhesive label that is easy to recycle, a method for recycling a container with an adhesive label, and an adhesive label for affixing to polyethylene terephthalate containers. [Means for solving the problem]

[0005] As a result of extensive research, the inventors discovered that by using an adhesive label containing a specific paper base material that floats on water, the adhesive label can be easily separated from the PET bottle during the cleaning process, and thus arrived at the present invention.

[0006] That is, the present invention relates to a container with an adhesive label, which has an adhesive label affixed to the container, the adhesive label having a paper-containing support and an adhesive layer in that order, the specific gravity of the paper-containing support being 1 or less, the adhesive layer being made of an adhesive, and the adhesive being such that when the container with the adhesive label is immersed in a 2% alkaline aqueous solution at 70°C or higher and 90°C or lower, the adhesive does not remain on the surface of the container and the adhesive label falls off within 15 minutes.

[0007] The paper-containing support preferably has poor water absorption or no water absorption when immersed in a 2% aqueous alkaline solution at 70° C. or higher and 90° C. or lower for 15 minutes.

[0008] It is preferable that the paper-containing support does not disintegrate when immersed in a 2% aqueous alkaline solution at 70° C. or higher and 90° C. or lower for 15 minutes.

[0009] The container is preferably made of polyethylene terephthalate.

[0010] The adhesive label is preferably affixed to at least a portion of the outer periphery of the container.

[0011] The adhesive layer is preferably provided over the entire surface of one side of the paper-containing support.

[0012] Another invention is a method for recycling containers with adhesive labels, which are polyethylene terephthalate containers to which an adhesive label has been affixed, the adhesive label having a paper-containing support and an adhesive layer, in that order, the method comprising the steps of: recovering the containers with the adhesive labels; washing the recovered containers with the adhesive labels with an alkaline aqueous solution and removing the adhesive labels from the polyethylene terephthalate containers in the alkaline aqueous solution; and separating and recovering the polyethylene terephthalate containers and the adhesive label residue due to the difference in specific gravity between the polyethylene terephthalate containers and the adhesive label.

[0013] The method for recycling containers with adhesive labels of the present invention preferably further includes a step of repulping the residue of the adhesive labels.

[0014] Yet another invention is an adhesive label to be affixed to polyethylene terephthalate containers, the adhesive label having, in that order, a paper-containing support and an adhesive layer, the specific gravity of the paper-containing support being 1 or less, the adhesive layer being made of an adhesive, the adhesive being such that when the polyethylene terephthalate container to which the adhesive label is affixed is immersed in a 2% alkaline aqueous solution at 70°C or higher and 90°C or lower, the adhesive label detaches within 15 minutes without remaining on the surface of the polyethylene terephthalate container. Effect of the Invention

[0015] According to the present invention, it is possible to obtain a container with an adhesive label that is easy to recycle, a method for reusing a container with an adhesive label, and an adhesive label for attachment to a polyethylene terephthalate container. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing one embodiment of a container with an adhesive label of the present invention. [Diagram 2] 1 is a schematic cross-sectional view showing one embodiment of an adhesive label of the present invention. [Diagram 3]1 is a process flow showing one embodiment of a method for recycling a container with an adhesive label of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [Container with adhesive label] A container 10 with an adhesive label according to one embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, an adhesive-labeled container 10 of this embodiment comprises a container 11 with an adhesive label 12 affixed thereto. Examples of the container 11 include glass and resin. Examples of the resin include polyester resin such as polyethylene terephthalate, and polyolefin resin such as polyethylene, polypropylene, and ethylene-vinyl alcohol copolymer. Polyolefin resin is used as a material for packaging containers for liquid components such as shampoo and solid components such as food. Among these, polyester resin is preferred, and containers made of polyethylene terephthalate are called PET bottles. PET bottles are particularly suitable for use as beverage containers.

[0018] (adhesive labels) As shown in Fig. 2, the adhesive label 12 has a paper-containing support 21 and an adhesive layer 22 in this order. The adhesive label 12 is used by attaching the adhesive layer 22 side to a container 11 (see Fig. 1). The adhesive label 12 only needs to be attached to at least a part of the outer circumferential surface of the container 11, and may be attached to a part of the vertical direction of the container 11 so as to cover the entire outer periphery of the body. The configuration of the adhesive label 12 will be described below.

[0019] <Paper-containing support> The specific gravity of the paper-containing support 21 is equal to or less than 1. Since the paper-containing support 21 has a specific gravity of equal to or less than 1, the difference in specific gravity between the polyethylene terephthalate container and the adhesive label residue can be utilized, allowing them to be separated and recovered. Furthermore, the paper-containing support 21 is preferably poorly water-absorbent or non-water-absorbent when immersed for 15 minutes in a 2% alkaline aqueous solution at 70° C. to 90° C. If highly water-absorbent paper such as fine paper, medium-quality paper, coated paper, art paper, or cast-coated paper is used as the paper-containing support 21, the paper-containing support 21 may absorb the alkaline aqueous solution in the step of washing with the alkaline aqueous solution, causing the specific gravity to exceed 1, making it difficult to separate and recover the paper. Furthermore, it is preferable that the paper-containing support 21 does not defibrate when immersed for 15 minutes in a 2% alkaline aqueous solution at 70° C. to 90° C. If the paper-containing support 21 is one that is defibrated in an alkaline aqueous solution, it becomes difficult to separate and recover it.

[0020] Examples of such paper-containing support 21 having a specific gravity of 1 or less include (1) waterproof paper, (2) greaseproof paper, and (3) so-called polylaminated paper in which polyethylene is laminated onto fine paper or glassine paper. (1) Waterproof paper or (2) oil-resistant paper can be, for example, configured such that a water-resistant or oil-resistant resin layer (such as a fluorine-based coating layer, an acrylic resin-based coating layer, or a styrene-acrylic resin-based coating layer) is provided on at least one surface of a paper base layer. In addition, (1) waterproof paper and (2) greaseproof paper can be produced by a known papermaking method from a pulp slurry containing pulp raw materials (pulp fibers such as wood pulp, synthetic fibers, chemical fibers, etc.), fillers, water-resistant agents, oil-resistant agents, wet strength agents, other additives, etc. Addition of the fillers, water-resistant agents, oil-resistant agents, wet strength agents, other additives, etc. may be performed either by an internal addition method in which the fillers are added to the pulp slurry during papermaking, or by an external addition method in which the fillers are impregnated in a size press or the like after papermaking, or a combination of both.

[0021] The thickness of the paper-containing support 21 in the present invention is preferably 20 to 150 μm. The lower limit of the thickness is more preferably 30 μm or more, even more preferably 35 μm or more, and even more preferably 40 μm or more. The upper limit of the thickness is more preferably 100 μm or less, even more preferably 80 μm or less, and even more preferably 70 μm or less. Within such a range, sufficient strength can be imparted for use in an adhesive label to be affixed to the surface of a polyethylene terephthalate container.

[0022] <Adhesive layer> The adhesive layer 22 of the adhesive label 12 in the present invention is made of an adhesive, and when the container 10 with the adhesive label is immersed in a 2% alkaline aqueous solution at 70°C or higher and 90°C or lower, the adhesive does not remain on the surface of the container 11 and the adhesive label falls off within 15 minutes. Such adhesives are also called wash-off adhesives.

[0023] Such an adhesive layer 22 can be formed from a water-dispersed adhesive composition. The water-dispersed adhesive composition is not particularly limited and any known composition can be used. For example, an acrylic water-dispersed adhesive composition is suitable.

[0024] The method for applying the pressure-sensitive adhesive is not particularly limited, and any conventionally known application method can be used, such as a method using an application device such as a knife coater, a roll coater, a roll knife coater, a gravure coater, a variogravure coater, an air knife coater, a bar coater, a die coater, or a curtain coater.

[0025] The thickness of the adhesive layer is not particularly limited, but is usually 10 to 50 μm, and preferably 12 to 30 μm.

[0026] [How to recycle containers with adhesive labels] The process flow of the method for recycling containers with adhesive labels of the present invention is shown in FIG. As shown in Figure 3, the method for recycling containers with adhesive labels of the present invention is a method for recycling containers with adhesive labels in which an adhesive label is affixed to a polyethylene terephthalate container, where the adhesive label has a paper-containing support and an adhesive layer, in that order, and includes a step (1) of recovering the containers with the adhesive labels, a step (2) of washing the recovered containers with the adhesive labels with an alkaline aqueous solution and removing the adhesive labels from the polyethylene terephthalate containers in the alkaline aqueous solution, and a step (3) of separating and recovering the polyethylene terephthalate containers and the adhesive label residue due to the difference in specific gravity between the polyethylene terephthalate containers and the adhesive label.

[0027] (Step (1) of collecting containers with adhesive labels) Used containers with adhesive labels, such as PET bottles, are collected from homes, offices, public facilities, etc. in accordance with the regulations of each local government, and transported to a recycling plant.

[0028] (Step (2) of removing the adhesive label) The collected containers with adhesive labels are first washed with an alkaline aqueous solution after removing foreign matter that cannot be recycled (regenerated). Examples of the alkaline aqueous solution include 2% to 10% alkaline aqueous solutions. The treatment temperature is preferably 70°C or higher and 90°C or lower. When washing containers with adhesive labels with an alkaline solution, it is also preferable to wash them under ultrasonic vibration. It is also preferable that the alkaline solution is stirred during washing. The time for immersing containers with adhesive labels in an alkaline solution is generally in the range of 2 minutes to 48 hours. If the immersion time is less than 2 minutes, there is a risk that the adhesive label will not completely peel off from the container and a part of it will remain. The number of times that the containers are immersed in the alkaline solution may be one or several times. When immersing multiple times, the concentration of the alkaline solution may be changed. It is also preferable to appropriately add known steps such as washing with water and drying during this time.

[0029] The collected containers with adhesive labels may be crushed into flakes before or after washing with an alkaline aqueous solution. The adhesive labels are detached and removed from the polyethylene terephthalate containers in the alkaline aqueous solution without leaving any residue.

[0030] (Process (3) of sorting and recovering) The residue of the adhesive label detached from the polyethylene terephthalate container floats in the alkaline aqueous solution because it has a smaller specific gravity than the polyethylene terephthalate, while the polyethylene terephthalate sinks in the alkaline aqueous solution. Due to this difference in specific gravity, the polyethylene terephthalate container and the adhesive label residue are separated and recovered.

[0031] The method for recycling containers with adhesive labels of the present invention makes it easy to separate the adhesive labels from the polyethylene terephthalate, facilitating recycling.

[0032] The method for recycling a container with an adhesive label of the present invention preferably further includes a step of repulping the residue of the adhesive label. The repulping can be performed by a known method. Since the adhesive label has a paper-containing support, it can be repulped, and the recycling method of the present invention is more environmentally friendly.

[0033] According to the method for recycling containers with adhesive labels of the present invention, the specific gravity of the adhesive label is smaller than that of polyethylene terephthalate, so that the label can be easily separated in an aqueous solution, thereby simplifying the work process and achieving high efficiency in the recycling process.

[0034] [Adhesive labels for affixing to polyethylene terephthalate containers] The adhesive label for attachment to polyethylene terephthalate containers of the present invention comprises, in this order, a paper-containing support and an adhesive layer, the specific gravity of the paper-containing support being 1 or less, the adhesive layer being made of an adhesive, and the adhesive being such that when a polyethylene terephthalate container to which the adhesive label is attached is immersed in a 2% aqueous alkaline solution at 70°C or higher and 90°C or lower, the adhesive label detaches from the surface of the polyethylene terephthalate container within 15 minutes without remaining thereon. As such an adhesive label, the above-mentioned adhesive label 12 is suitable, and has the advantage that the adhesive label can be easily separated from the polyethylene terephthalate, and recycling can be easily carried out. EXAMPLES

[0035] The present invention will be described below with reference to examples and comparative examples.

[0036] [Container with adhesive label] [Example 1] The adhesive-labeled container of Example 1 was produced as follows. (container) A 500 ml PET bottle was prepared.

[0037] (adhesive labels) An adhesive (adhesive layer) was provided on the entire surface of one side of the following paper-containing support to prepare an adhesive label. Paper-containing support: Oil- and water-resistant paper (thickness 122 μm, basis weight 91.9 g / m 2 (Manufactured by Lintec Corporation) Adhesive: Wash-off adhesive (Toyochem EXK23-065, thickness 15g / m 2 ) Adhesive label size: 3cm x 5cm

[0038] The adhesive layer side of the adhesive label was attached to the body of a PET bottle to prepare a container with an adhesive label.

[0039] [Comparative Example 1] A container with an adhesive label was produced in the same manner as in Example 1, except that the paper-containing support was made of fine paper.

[0040] [evaluation] The following evaluations were carried out for the above-mentioned Examples and Comparative Examples. The evaluation results are shown in Table 1.

[0041] (Wash-off evaluation) Thereafter, the container with the adhesive label was immersed in a 2% NaOH aqueous solution at 80° C., and the peeling state of the adhesive label was checked over time and evaluated according to the following evaluation criteria. <Evaluation criteria> 〇: The adhesive label peels off completely within 15 minutes, leaving no residue ×: The adhesive label does not peel off.

[0042] (Appearance evaluation) The state of the adhesive label that had been detached in the wash-off evaluation was visually observed and evaluated according to the following criteria. (1) Buoyancy 〇: Floats in water ×: Settles in water (2) Contamination ○: No defibration of the paper-containing support in the cleaning solution ×: There is disintegration of the paper-containing support into the washing container.

[0043] [Table 1]

[0044] As shown in Table 1, when a container with an adhesive label of the present invention is immersed in a 2% NaOH aqueous solution at 80°C, the adhesive label detaches from the container and floats in the aqueous solution without contaminating it, allowing the PET and the adhesive label to be easily separated, making it easy to recycle. [Explanation of symbols]

[0045] 10 Containers with adhesive labels 11 Container 12 Adhesive Labels 21 Paper-containing support 22 Adhesive layer

Claims

1. A container with an adhesive label, the container having an adhesive label attached thereto, The adhesive label has a paper-containing support and an adhesive layer in this order, The specific gravity of the paper-containing support is 1 or less; The adhesive layer is made of an adhesive, The adhesive is a container with an adhesive label, and when the container with the adhesive label is immersed in a 2% alkaline aqueous solution at 70°C or higher and 90°C or lower, the adhesive does not remain on the surface of the container and the adhesive label is removed within 15 minutes.

2. 2. A container with an adhesive label according to claim 1, wherein the paper-containing support has poor water absorption or no water absorption when immersed in a 2% aqueous alkaline solution at 70° C. or higher and 90° C. or lower for 15 minutes.

3. 2. A container with an adhesive label according to claim 1, wherein the paper-containing support does not disintegrate when immersed in a 2% aqueous alkaline solution at 70° C. or higher and 90° C. or lower for 15 minutes.

4. 2. The container with an adhesive label according to claim 1, wherein the container is made of polyethylene terephthalate.

5. 2. The container with an adhesive label according to claim 1, wherein the adhesive label is attached to at least a portion of the outer circumferential surface of the container.

6. 6. The container with an adhesive label according to claim 1, wherein the adhesive layer is provided over the entire surface of one side of the paper-containing support.

7. A method for recycling a container with an adhesive label, which is a polyethylene terephthalate container with an adhesive label attached thereto, comprising the steps of: The adhesive label has a paper-containing support and an adhesive layer in this order, Recovering the containers with the adhesive labels; a step of washing the collected containers with adhesive labels with an alkaline aqueous solution and removing the adhesive labels from the polyethylene terephthalate containers in the alkaline aqueous solution; a step of separating and recovering the polyethylene terephthalate container and the adhesive label residue based on the difference in specific gravity between the polyethylene terephthalate container and the adhesive label; A method for recycling a container with an adhesive label.

8. 8. The method for recycling containers with adhesive labels according to claim 7, further comprising a step of repulping the residue of the adhesive labels.

9. An adhesive label for attachment to a polyethylene terephthalate container, comprising: The adhesive layer includes a paper-containing support and an adhesive layer in this order. The specific gravity of the paper-containing support is 1 or less; The adhesive layer is made of an adhesive, The adhesive is an adhesive label for attachment to polyethylene terephthalate containers, which, when the polyethylene terephthalate container to which the adhesive label is affixed is immersed in a 2% alkaline aqueous solution at 70°C or higher and 90°C or lower, causes the adhesive label to detach within 15 minutes without remaining on the surface of the polyethylene terephthalate container.

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