JP2023051162A - Method for removing ink layer, method for recycling label, and method for manufacturing plastic product - Google Patents

Abstract

To efficiently remove an ink layer from a label.SOLUTION: A method for removing an ink layer according to an aspect of the present invention includes solution treatment step (S71) for bringing a label piece (71) having an ink layer into contact with an ink removing solution (80). Before the solution treatment step (S71), the label piece (71) is brought into contact with the ink removing solution (80) without pre-heating a label (11).SELECTED DRAWING: Figure 1

Description

The present invention relates to an ink layer removing method for removing an ink layer from a label.

Conventionally, plastic products such as polyethylene terephthalate bottles have been widely used. From the viewpoint of resource saving and environmental protection, there is a demand for reusing plastic products such as PET bottles.

Among plastic products, the reuse of PET bottles in particular has already spread. On the other hand, plastic labels printed to display product information, etc., are sometimes attached to the body of PET bottles, but the reuse of these labels has lagged behind the spread of PET bottles. .

One factor that hinders the reuse of labels is the inability to efficiently remove the ink layer from the label. This is because if the ink layer cannot be efficiently removed from the label, it is not possible to produce useful pellets from the label.

For example, in Patent Document 1, after preheating a shrink label (heat-shrinkable label) under non-water immersion conditions, it is brought into contact with relatively low-temperature alkaline water to desorb and remove an alkaline water-releasable ink layer. A method is disclosed.

Japanese Patent Application Laid-Open No. 2001-350411

It is possible to remove the ink layer by the method described in Patent Document 1. However, in the method described in Patent Document 1, it is necessary to preheat the shrink label at a temperature of about 100° C. to shrink it before detachment of the ink layer, and a more efficient method for removing the ink layer is desired. It had been.

An object of one aspect of the present invention is to provide an ink layer removing method capable of efficiently removing an ink layer from a label.

In order to solve the above problems, a method for removing an ink layer according to aspect 1 of the present invention is a method for removing an ink layer from a label having an ink layer, the method comprising dissolving or swelling an aqueous ink layer. and a component that dissolves or swells the oil-based ink layer. The label is contacted with the deinking solution without heat.

In the method, the deinking solution contains both a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer. Therefore, in the solution treatment step, the water-based ink layer and the oil-based ink layer are dissolved or swollen at the same time, and the ink layer can be detached and removed from the label.

Further, in the method, the ink layer is dissolved or swollen by contacting the label with the ink removing solution in the solution treatment step without preheating the label having the ink layer before the solution treatment step. For this reason, the preheating process, which has conventionally been performed before detachment of the ink layer, can be omitted, and the number of processes and the energy consumption required for preheating can be reduced.

Therefore, according to the method, the water-based ink layer and the oil-based ink layer can be efficiently removed from the label.

Further, in the method for removing an ink layer according to aspect 2 of the present invention, in aspect 1, the ink removing solution may contain sodium hydroxide, potassium hydroxide, a surfactant, a glycol ether and a high-boiling solvent. good.

According to the above method, the water-based ink layer and the oil-based ink layer can be dissolved or swollen at normal temperature (room temperature) by contacting the label with an ink removing solution containing these components.

In the ink layer removing method according to aspect 3 of the present invention, in the aspect 1 or 2, the temperature of the ink removing solution may be 15°C or higher and lower than 65°C.

According to the method, even if the label is a shrink label, the ink layer can be safely and efficiently removed from the shrink label without heat shrinking the shrink label in the solution treatment process. In addition, since the treatment can be performed at a lower temperature than the conventional alkali treatment, energy consumption can be reduced and the energy cost is also excellent.

Further, in the method for removing an ink layer according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, the ink removing solution comprises an aqueous ink removing agent containing a component that dissolves or swells the aqueous ink layer; It may be a mixture obtained by mixing an oily ink remover containing a component that dissolves or swells the oily ink layer.

According to the method, it is possible to easily prepare an ink-removing solution containing both a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer.

Further, in the method for removing an ink layer according to aspect 5 of the present invention, in any one of aspects 1 to 4, a water treatment step of contacting the label having the ink layer with water after the solution treatment step is further included. You can stay.

In the above method, the ink layer can be detached and removed by contacting the label having the ink layer with water after reducing the adhesion of the ink layer in the solution treatment step. Therefore, according to the above method, the ink removing solution can be efficiently reused since the change in the characteristics of the ink removing solution is small.

In order to solve the above-mentioned problems, a label recycling method according to aspect 6 of the present invention is a label having a water-based ink layer and a label having an oil-based ink layer, according to the method for removing an ink layer according to any one of aspects 1 to 5. and a step of producing resin fluff or resin pellets using the label from which the ink layer has been removed.

According to the above method, resin fluff or resin pellets can be produced using a label from which the water-based ink layer and the oil-based ink layer have been efficiently removed without preheating.

In order to solve the above-described problems, a method for manufacturing a plastic product according to aspect 7 of the present invention is a step of manufacturing a plastic product using the resin fluff or resin pellets manufactured by the label recycling method of aspect 6. including.

According to the above method, plastic products can be produced using resin fluff or resin pellets produced from labels from which the water-based ink layer and the oil-based ink layer have been efficiently removed without preheating.

According to one aspect of the present invention, the ink layer can be efficiently removed from the label.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the flow of the removal method of the ink layer which concerns on embodiment of this invention.

An embodiment of the present invention will be described below with reference to FIG. However, the following description is an example of the ink layer removing method according to the present invention, and the technical scope of the present invention is not limited to the illustrated examples.

FIG. 1 is a schematic diagram showing an example of the flow of the ink layer removing method according to the present embodiment. As shown in FIG. 1, the method for removing the ink layer includes a bottle recovery step S1, a compression step S2, an accumulation step S3, a separation step S4, a sorting step S5, a crushing step S6, a detachment step S7 and a separation/collection step S8. include. Each step of the method for removing the ink layer will be described below with reference to FIG.

<Bottle collection process>
First, as shown in S1 of FIG. 1, used PET bottles (articles) 10 are collected in a collection box 12. In FIG. A label 11 having an ink layer is attached to the body of the PET bottle 10 . The ink layer is a printing layer on which a design such as product display is printed.

The article to which the label 11 is attached is not limited to the PET bottle 10 . The article may be anything that is used with the label 11 attached, and may be a container other than the PET bottle 10 or various molded articles other than the container. Similarly, the type of the label 11 is not particularly limited, and various labels such as shrink labels, wrap labels (roll labels) and stretch labels may be used.

The label 11 has, for example, a water-based ink layer or an oil-based ink layer on at least one side of a film (base material). A film used for the label 11 is appropriately selected according to the type of the label 11 .

For example, when the label 11 is a shrink label, a heat-shrinkable shrink film is used as the substrate. Examples of shrink films include polyester films made of polyethylene terephthalate, polyethylene naphthalate, etc., styrene films made of styrene-butadiene block copolymers, etc., olefin films made of olefin resins such as polyethylene and polypropylene, and vinyl chloride resins. Examples include a vinyl chloride film made of. These may be foamed films.

The heat shrinkage of the shrink film in at least one direction (main shrinkage direction) is preferably 30% or more, more preferably 50% or more, from the viewpoint of shrinkage adhesion to various containers. The thickness of the shrink film can be appropriately selected in consideration of the handleability of the label 11 and the like, and can be, for example, about 10 μm to 100 μm, preferably about 15 μm to 60 μm. The numerical values of these shrink films are the numerical values of the shrink film used for making the shrink label before being attached to the PET bottle 10 or other container.

The film used for the label 11 may be a single layer or a laminate of two or more layers. When constructing a laminate of two or more layers, each layer may be of the same kind or different. Moreover, the color of the film is not particularly limited, and may be, for example, milky white or transparent.

The film may optionally be subjected to a surface treatment such as corona discharge treatment, or may be provided with an anchor coat layer, in order to enhance adhesion to the ink layer. The anchor coat layer can be formed using a conventionally known anchor coat agent or the like.

The ink layer is formed of ink that dissolves or swells in the ink removing solution 80 used in the later-described desorption step S7. The ink that forms the ink layer may be either water-based ink or oil-based ink.

As the water-based ink and the oil-based ink that form the ink layer, conventionally known inks used for label printing and the like can be used. As the oil-based ink, for example, one obtained by blending an additive with a coloring agent such as a pigment or a dye, a binder resin and an organic solvent may be used. As the water-based ink, a colorant mixed with a water-soluble or water-dispersible binder resin, an additive, or the like may be used. Additives include lubricants, antiblocking agents, antisettling agents, and the like.

As a method of forming an ink layer on the surface of the film, for example, a method of forming an ink layer on the film by gravure printing, flexographic printing, screen printing, inkjet printing, or the like can be used. The ink layer may be a single layer or multiple layers. The thickness of the ink layer can be appropriately selected depending on the application and the like, and can be, for example, about 0.1 μm or more and 100 μm or less.

<Compression process>
Next, as shown in S2 of FIG. 1, the collected PET bottles 10 with the labels 11 attached thereto are compressed to form labeled bales 20. Next, as shown in FIG.

<Integration process>
Next, as shown in S3 of FIG. 1, the labeled bales 20 are sent to the recycling plant 30 and accumulated.

<Separation process>
Next, as shown in S4 of FIG. 1, in the recycling plant 30, the label 11 is removed from the PET bottle 10 of the labeled bale 20, and the PET bottle 10 and the label 11 are separated. The label 11 separated from the PET bottle 10 may include various labels such as shrink labels, wrap labels and stretch labels.

In the illustrated example, the label 11 separated from the PET bottle 10 is a shrink label 11a and a wrap label 11b. The PET bottle 10 from which the label 11 has been separated is reused, for example, in an existing recycling process. In particular, according to the later-described detachment step S7, both the water-based ink layer and the oil-based ink layer can be detached. Therefore, the label 11 separated from the PET bottle 10 in the separation step S4 and sent to the subsequent step must be separated into a label having an ink layer made of water-based ink and a label having an oil-based ink layer made of oil-based ink. no sex.

<Sorting process>
Next, as shown in S5 of FIG. 1, the labels 11 are sorted. In the sorting step S5, the labels 11 are sorted, for example, by the type of film or material used for the labels 11 . The illustrated example shows a state in which each type of film used for the label 11, that is, the shrink label 11a and the wrap label 11b is sorted and collected.

The labels 11 sorted in the sorting step S5 are separately subjected to the subsequent crushing step S6, detachment step S7 and separation/recovery step S8. As a result, when the film pieces 91 from which the ink layer has been removed are collected in the separation/recovery step S8, only the film pieces 91 of the same type or material are collected. Therefore, by performing the sorting step S5, it becomes easier to collect the film pieces 91 by type or material.

Note that the sorting step S5 is not essential and can be omitted. Further, for example, after the film pieces 91 are collected in the separation/recovery step S8, the film pieces 91 may be sorted by type or material.

<Crushing process>
Next, as shown in S6 of FIG. 1, the label 11 is crushed by the crusher 70 to produce the label piece 71. Next, as shown in FIG. In the crushing step S6, the label 11 is crushed into smaller label pieces 71 prior to removing the ink layer from the label 11 in the subsequent detachment step S7. In this way, the ink layer can be efficiently removed from the label piece 71 in the separating step S7 by performing the detaching step S7 while the label 11 is attached to the smaller label piece 71 .

A method for crushing the label 11 is not particularly limited. The label 11 is crushed into a size (for example, several cm square) that can efficiently remove the ink layer from the label piece 71 in the detachment step S7, which will be described later.

Note that the crushing step S6 is not essential and can be omitted. In this case, the detachment step S<b>7 is performed in the state of the label 11 .

<Desorption process>
Next, as shown in S7 of FIG. 1, the ink layer is detached from the label piece 71 and removed. The desorption step S7 includes a solution treatment step S71 and a water treatment step S72.

(Solution treatment step)
The solution treatment step S<b>71 is a step of bringing the label piece 71 into contact with the ink removing solution 80 . In this solution treatment step S71, for example, the label piece 71 is put into the ink removing solution 80 in the solution bath 82 and is gently immersed for about 10 minutes. The temperature of the ink removing solution 80 at this time can be normal temperature (approximately 15° C. or higher and 25° C. or lower) or room temperature (1° C. or higher and 30° C. or lower). As a result, complete detachment of the ink layer from the label piece 71 can be suppressed in the ink removing solution 80 while the adhesion of the ink layer can be reduced. The temperature of the ink removing solution 80 means the surface temperature of the label piece 71 during the solution treatment step S71. Also, "gentle immersion" means that the ink removing solution 80 is not agitated or immersed very gently so as not to cause complete detachment of the ink layer.

The temperature of the ink removing solution 80 in the solution bath 82 may be normal temperature (room temperature). may be higher. However, when a shrink label piece is included as the label piece 71, the shrink film thermally shrinks and the label piece 71 curls when the temperature of the ink removing solution 80 reaches 65° C. or higher. It is difficult to remove the ink layer from the curled label piece 71, resulting in a significant drop in ink layer removal efficiency. Therefore, from the viewpoint of avoiding unintended shrinkage of the label piece 71, the temperature of the ink removing solution 80 is preferably in a temperature range in which the shrink film does not thermally shrink, for example, 15°C or more and less than 65°C. As a result, the ink layer can be safely and efficiently removed from the label piece 71 without heat shrinking the shrink label in the solution treatment step S71.

Thus, the ink removing solution 80 dissolves or swells the ink layer within a temperature range where thermal shrinkage of the shrink film does not occur. For this reason, the preheating process, which has conventionally been performed before detachment of the ink layer, can be omitted, and the number of processes and the energy consumption required for preheating can be reduced.

The ink removing solution 80 is alkaline with a pH of about 11 to 14, and contains a component that dissolves or swells the water-based ink layer and the oil-based ink layer at normal temperature (room temperature). That is, the ink removing solution 80 contains both a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer. Therefore, the water-based ink layer and the oil-based ink layer can be dissolved or swollen at the same time, and the ink layer can be detached and removed from the label piece 71 .

The ink removing solution 80 may contain, for example, sodium hydroxide, potassium hydroxide, a surfactant, a glycol-based solvent (eg, glycol ether, etc.), a high boiling point solvent (eg, polymer alcohol, etc.), and the like. By contacting the label with an ink removing solution containing these components, the water-based ink layer and the oil-based ink layer can be dissolved or swollen at room temperature.

Also, the ink removing solution 80 is a mixture of a water-based ink removing agent containing a component that dissolves or swells the water-based ink layer and an oil-based ink removing agent that contains a component that dissolves or swells the oil-based ink layer. There may be. As a result, the ink removing solution 80 containing both the component that dissolves or swells the water-based ink layer and the component that dissolves or swells the oil-based ink layer can be easily produced.

The water-based ink remover is not particularly limited as long as it dissolves or swells the water-based ink layer at room temperature. The water-based ink remover may be, for example, a remover for water-based inks that is commercially available for removing water-based inks, or an agent that is commercially available for uses other than removing water-based inks (removers, cleaning agents, etc.). agents, etc.).

As such a water-based ink remover, for example, the product name "Ventilator Range Cleaner PRO" (manufactured by Rinrei Co., Ltd.) can be suitably used. Table 1 below is a table showing an example of the composition/components of a water-based ink remover (product name: "ventilating fan range cleaner PRO") that can be suitably used for manufacturing the ink removing solution 80 .

表１に示すように、水性インキ除去剤は、例えば、水、グリコール系溶剤（グリコールエーテル）、両性イオン系界面活性剤（アルキルベタイン）、水酸化ナトリウム、水酸化カリウムおよび金属封鎖剤等を含むことができる。

As shown in Table 1, aqueous ink removers include, for example, water, glycol solvents (glycol ethers), zwitterionic surfactants (alkylbetaines), sodium hydroxide, potassium hydroxide and sequestering agents. be able to.

The oil-based ink remover is not particularly limited as long as it dissolves or swells the oil-based ink layer at room temperature. The oily ink remover may be, for example, a remover for oily ink that is commercially available for removing oily ink, or an agent that is commercially available for uses other than removing oily ink (removing agent, cleaning agent, agents, etc.).

As such an oil-based ink removing solution, for example, the product name "PAINTSOLV-W" manufactured by Infinity Co., Ltd. can be suitably used. Table 2 below is a table showing an example of the composition/components of an oil-based ink remover (product name “PAINTSOLV-W”) that can be suitably used for manufacturing the ink removing solution 80 .

表２に示すように、油性インキ除去剤は、例えば、高沸点溶剤（高分子アルコール系溶剤）、非イオン系界面活性剤（ラウリルグルコシド）等を含むことができる。

As shown in Table 2, the oily ink remover can contain, for example, a high boiling point solvent (high molecular weight alcohol solvent), a nonionic surfactant (lauryl glucoside), and the like.

By mixing the water-based ink remover containing the components shown in Table 1 and the oil-based ink remover containing the components shown in Table 2 at a ratio of, for example, 1:9, the water-based ink layer and the oil-based ink layer are dissolved at room temperature. Alternatively, a swelling ink removing solution 80 can be suitably produced.

(Water treatment process)
The water treatment step S72 is a step of bringing the label piece 71 having the ink layer into contact with water 84 after the solution treatment step S71. In the water treatment step S72, the label piece 71 taken out from the solution tank 82 is immersed in the water 84 in the water tank 86 and stirred. In the illustrated example, a screw 88 rotatably provided at the bottom of a water tank 86 stirs the water 84 in which the label pieces 71 are immersed. By stirring the water 84 in which the label piece 71 is immersed, the ink layer is removed from the label piece 71 in the water 84 . For example, if the label piece 71 has an oil-based ink layer, the label piece 71 is separated into the film piece 91 and the ink coating 93 . Also, when the label piece 71 has a water-based ink layer, the label piece 71 is separated into the film piece 91 and the ink coating 93 . If the label piece 71 has a water-based ink layer, the ink layer may be dissolved and dispersed in the water 84 .

Although the temperature of the water 84 in the water tank 86 is not particularly limited, it is preferably about room temperature (around 27° C.) from the viewpoint of avoiding unintended shrinkage of the label piece 71 .

Thus, in the desorption step S7, first, the label piece 71 is gently immersed in the ink removing solution 80 in the solution treatment step S71. As a result, complete separation of the ink layer from the label piece 71 is suppressed in the ink removing solution 80, and the adhesion between the two is reduced. At this time, since the ink removing solution 80 dissolves or swells the water-based ink layer and the oil-based ink layer at room temperature, the preheating process, which is conventionally performed before the ink layer is removed from the label 11, can be omitted. Then, in the subsequent water treatment step S72, the ink layer can be removed from the label piece 71 by immersing the label piece 71 in the water 84 and stirring.

The ink removing solution 80 after the label piece 71 has been immersed may be discarded as a waste liquid, or may be reused as the ink removing solution 80 . When the desorption step S7 includes the water treatment step S72 as in this embodiment, the change in the characteristics of the ink removing solution 80 is small. Therefore, the ink removing solution 80 can be reused more efficiently. The change in the characteristics of the ink removing solution 80 includes, for example, contamination of a large amount of ink layer.

Also, the water treatment step S72 is not essential and can be omitted. In this case, in the solution treatment step S71, the label piece 71 may be immersed in the ink removing solution 80 in the solution bath 82 and agitated. As a result, the ink layer can be detached and removed from the label piece 71 .

<Separation/recovery process>
Next, as shown in S8 of FIG. 1, the film piece 91 and the ink film 93 in the water tank 86 are separated and recovered. For example, a first net 90 having relatively large openings collects the film piece 91 after the ink layer has detached from the label piece 71, and a second net 92 having relatively small openings collects the film. Ink coatings 93 smaller than strips 91 are collected. The ink coating film 93 is a film formed by finely dividing the oil-based ink layer removed from the label piece 71 in the detachment step S7.

Thereafter, the film piece 91 collected by the first net 90 is used as a plastic raw material for manufacturing plastic products such as resin fluff or resin pellets obtained by repelletizing the film piece 91 (resin repellet), for example, manufacturing labels. can be reused for Also, by mixing the film piece 91 into the raw material of a new label, it can be reused as a label. On the other hand, the ink coating 93 collected by the second net 92 can be reused, for example, in a thermal recycling process.

Note that the water-based ink detached from the label piece 71 in the detaching step S7 dissolves and disperses in the water 84 . Therefore, when recovering water-based ink or water-based ink and oil-based ink, sedimentation, centrifugation, solvent volatilization, extraction, filtration, flocculation separation, and other recovery methods can be employed in the separation/recovery step S8.

<Summary>
As described above, the method for removing an ink layer according to the present embodiment is a method for removing an ink layer from a label 11 having an ink layer. including a solution treatment step S71 of contacting the label 11 having the ink layer with an ink removing solution 80 containing a component that dissolves or swells the ink layer, and the label 11 having the ink layer is not preheated before the solution treatment step S71. Then, the label 11 is brought into contact with the deinking solution 80 .

In the ink layer removing method according to the present embodiment, the ink removing solution 80 contains both a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer. Therefore, in the solution treatment step S71, the water-based ink layer and the oil-based ink layer are dissolved or swollen at the same time, and the ink layer can be detached and removed from the label 11 .

Further, in the method for removing the ink layer according to the present embodiment, the label 11 having the ink layer is brought into contact with the ink removing solution 80 in the solution treatment step S71 without being preheated before the solution treatment step S71. Dissolve or swell the layer. For this reason, the preheating process, which has conventionally been performed before detachment of the ink layer, can be omitted, and the number of processes and the energy consumption required for preheating can be reduced.

Furthermore, the ink layer removing method according to the present embodiment can also be applied to various labels other than shrink labels, such as wrap labels and stretch labels, and can remove water-based ink layers and oil-based ink layers from various labels. can. Therefore, for example, it is not necessary to separately treat labels having an aqueous ink layer and labels having an oily ink layer, and the ink layer can be removed from a label group in which these labels are mixed.

Therefore, according to this embodiment, it is possible to realize an ink layer removing method capable of efficiently removing the water-based ink layer and the oil-based ink layer from the label 11 .

In addition, according to the ink layer removing method according to the present embodiment, the preheating step can be omitted, and the energy consumption required for preheating can be reduced. Also, it becomes possible to efficiently recycle labels that have conventionally been mainly thermally recycled. This will contribute to achieving the Sustainable Development Goals (SDGs).

An embodiment of the invention is described below. In this example, the removal rate of the ink layer by the method for removing the ink layer according to the present invention was verified.

First, using a 50 μm-thick PET-based shrink film (Mitsubishi Chemical Co., Ltd. Hisipet (registered trademark) LX-18S), a thickness of 50 μm × height (width) 15 cm × length (circumference) 24 cm was used. of shrink film was prepared. A first ink layer, a second ink layer and a third ink layer were laminated in this order on this shrink film using water-based ink to prepare a tubular shrink label (label 11) having water-based ink layers. Further, a first ink layer, a second ink layer and a third ink layer were laminated in this order on the same shrink film using oil-based ink to prepare a tubular shrink label (label 11) having an oil-based ink layer. .

Next, the shrink label having the water-based ink layer and the shrink label having the oil ink layer were individually coated on a cylindrical PET bottle having an outer diameter of 54 mm and thermally shrunk to prepare a shrink-labeled PET bottle. The shrinkage rate of the shrink label at this time was about 30%, and the area of the shrink label after mounting was about 70% of the area of the shrink label before mounting. Then, the shrink label was peeled off from the PET bottle to separate the PET bottle and the shrink label (separation step S4).

Next, the shrink label peeled off from the PET bottle was crushed to produce a substantially square shrink label piece (label piece 71) of length 40 mm×width 40 mm (crushing step S6).

Next, the shrink label piece was placed in the ink removing solution 80 in the solution bath 82 and gently immersed at room temperature (27° C.) for about 10 minutes (solution treatment step S71). A 500 ml beaker was used for the solution bath 82 . The ink removing solution 80 is prepared by putting 30 ml of a water-based ink remover (product name “ventilator range cleaner PRO”) and 270 ml of an oil-based ink remover (product name “PAINTSOLV-W”) into a solution tank 82 and mixing them. bottom.

Next, the shrink label piece taken out from the solution tank 82 was immersed in 300 ml of water 84 in a water tank 86 and stirred at 200 rpm for 5 minutes using a magnetic stirrer (water treatment step S72). A 500 ml beaker was used for the water tank 86 .

Next, the first net 90 having relatively large openings was used to collect the shrink label pieces from the water tank 86, and the remaining ink layer on each shrink label piece was checked. As a result, both the water-based ink layer and the oil-based ink layer were removed in the range of 70% or more and 100% or less in each shrink label piece.

This example confirmed that the water-based ink layer and the oil-based ink layer of the shrink label can be efficiently removed without preheating, according to the ink layer removing method of the present invention.

The present invention is not limited to the above-described embodiments, and can be modified in various ways within the scope of the claims. It is included in the technical scope of the invention.

11, 11a, 11b: labels,
80: Ink removing solution 84: Water S71: Solution treatment step S72: Water treatment step

Claims (7)

An ink layer removing method for removing an ink layer from a label having an ink layer, comprising:
a solution treatment step of contacting the label having the ink layer with an ink removing solution containing a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer;
A method of removing an ink layer, wherein the label having the ink layer is contacted with the ink removing solution without preheating the label having the ink layer prior to the solution treatment step. 2. The method of removing an ink layer according to claim 1, wherein the ink removing solution comprises sodium hydroxide, potassium hydroxide, a surfactant, a glycol ether and a high boiling point solvent. 3. The method of removing an ink layer according to claim 1, wherein the ink removing solution has a temperature of 15[deg.]C or higher and lower than 65[deg.]C. The ink removing solution is a mixture obtained by mixing an aqueous ink removing agent containing a component that dissolves or swells the aqueous ink layer and an oily ink removing agent containing a component that dissolves or swells the oily ink layer. Item 4. The method for removing an ink layer according to any one of Items 1 to 3. 5. The method of removing an ink layer according to any one of claims 1 to 4, further comprising a water treatment step of contacting the label having the ink layer with water after the solution treatment step. a step of removing an ink layer from a label group including a label having an aqueous ink layer and a label having an oily ink layer by the method for removing an ink layer according to any one of claims 1 to 5;
a step of producing resin fluff or resin pellets using the label from which the ink layer has been removed;
How to recycle the label, including: A method for manufacturing a plastic product, comprising a step of manufacturing a plastic product using the resin fluff or the resin pellet manufactured by the label recycling method according to claim 6.

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