JP2001042775A - Heat sensitive tacky adhesive label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label which can be wound and stuck around a container, does not allow a tacky adhesive to remain at the container when peeling the label off the container, is similarly peelable even after a pasteurization treatment and is adequate for containers to be recycled. SOLUTION: This thermosensitive tacky adhesive label 2 is provided with a layer which develops tacky adhesiveness of <=50 g/25 mm in blocking degree, for example, a layer of an ethylene-vinyl acetate copolymer of 25 to 25 mol% in vinyl acetate content and 5 to 200 melt index by gravure printing and is wound and stuck around a container 1 by heating the tacky adhesive layer of the label to 60 to 120 deg.C. The tacky adhesive power to the label surface after the sticking is >=100 g/25 mm, <=500 g/25 mm and the peeling strength to the container is 5 to 100 g/25 mm and, therefore, the label do not allow printing ink an the tacky adhesive to remain on the container at the time of peeling from the container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive adhesive label which is heated and wound around the entire surface of a container, and more particularly to a heat-sensitive adhesive label suitable for containers to be recycled.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of reducing the amount of waste and effectively utilizing resources, the movement of recycling used containers has been established. Various types of containers, such as glass bottles, plastic bottles, and paper packs, are usually provided with various labels from the viewpoints of container damage protection, contents display, and design. Since it is preferable that these can be easily separated from the container at the time of recycling, various labels and containers having the label attached thereto have been proposed. For example,
In Japanese Patent Application Laid-Open No. 4-279454, a rectangular label made of a printed plastic film is wrapped around the outer periphery of the body of a plastic bottle, and the front end of the back of the label is wrapped around the surface of the bottle, and the rear end is wrapped around the back end. A plastic bottle is disclosed, wherein the plastic bottle is bonded to the surface of each of the labels with a hot melt agent, and the adhesive strength between the plastic bottle and the hot melt agent is smaller than the adhesive strength between the hot melt agent and the label.

[0003]

However, this is because the hot melt is melted and used at a high temperature of 150 to 200 ° C. in the air, that is, in the presence of oxygen. Used at such a temperature), an unpleasant odor due to partial thermal decomposition of the hot melt agent is likely to remain on the label, the plastic film is easily deformed by heat, and furthermore, preparation before the start of the hot melt agent application operation or after the end of the operation However, there is a problem that it takes time to clean the application device including the hot melt application roller.

[0004] The first problem to be solved by the present invention is as follows.
An object of the present invention is to provide a heat-sensitive adhesive label more suitable for recycling, which solves the above problem. A second object is to provide a heat-sensitive adhesive label that is also suitable for pasting. A third object is to provide a container suitable for recycling.

[0005]

As a means for solving the above-mentioned problems, the present invention provides a heat-sensitive adhesive label which is heated and wound around the entire periphery of a container and has a blocking degree of 50 g / g.
A heat-sensitive adhesive layer having a thickness of 25 mm or less is preliminarily laminated on the entire surface of the plastic film, and a heating temperature of 60 mm or less is applied.
The adhesive is characterized in that the adhesive does not adhere to the container when it is peeled off from the container after heating at 120 ° C.

[0006] A printing ink layer is provided between the plastic film and the heat-sensitive adhesive layer.

[0007] It is characterized in that the adhesive layer does not adhere to the container when peeled from the container after the pastelizing treatment.

The material of the container contains one selected from the group consisting of polyester, glass and paper, and the plastic film is a biaxially oriented polypropylene film or a biaxially oriented polyester film.

The pressure-sensitive adhesive layer is characterized in that it is a layer mainly composed of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 25 to 35 mol% and a melt index of 5 to 200.

[0010] It is characterized in that the pressure-sensitive adhesive layer is a layer formed by gravure printing.

In one cut label, the thickness of the pressure-sensitive adhesive layer is formed to be thick at a portion where the back surface of the label overlaps the front surface and thin at a portion wound around the container.

The present invention is characterized in that it is a container to which a heat-sensitive adhesive label having the above-mentioned characteristics is attached.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described more specifically.

The heat-sensitive adhesive label of the present invention comprises at least two layers of a plastic film and a heat-sensitive adhesive layer. An example of a method for mounting the heat-sensitive adhesive label of the present invention on a container is as follows. First, the heat-sensitive adhesive layer is heated while unwinding the long label wound in a roll shape, and the heat-sensitive adhesive layer having the adhesive property is wound around the container from the leading end to the trailing end of the label. Attach. The rear end portion of the label, in which the container is wound one round, is superimposed on the front end portion of the label, and the label is cut into a predetermined size.

The heat-sensitive adhesive label of the present invention is a label obtained by previously laminating an adhesive which has no tack at room temperature but exhibits tack when heated, on the entire surface of a plastic film. In the case where the pressure-sensitive adhesive is laminated on a part of the plastic film instead of the entire surface, for example, in the case of a dot-like or intermittent linear shape, a gap is generated between the container and the label. Water drops generated when the product) is taken out of the refrigerated showcase penetrate between the container and the label, causing not only the appearance to deteriorate, but also the peeling strength between the container and the label due to the effect of the water drop, so that the product is lifted by hand. This causes problems such as the label being easily displaced from the container by the external force.

The label of the present invention has a degree of blocking between the non-adhesive side of the plastic film and the adhesive side (ie, the degree of blocking between the front and back sides of the label).
It is 50 g / 25 mm or less under the conditions described below.
If it exceeds 50 g / 25 mm, blocking occurs when a long heat-sensitive adhesive label laminated with an adhesive is stored in a roll form (particularly in the summer when the room temperature is high). A problem arises in that it cannot be unwound.

The label of the present invention is heated to 60 to 120 ° C., preferably 70 to 120 ° C., and more preferably 80 to 120 ° C. immediately before application in order to be wound and applied around the entire circumference of the container. . Since the heating temperature is such a low temperature, the pressure-sensitive adhesive does not thermally decompose, generating an odor, and the plastic film is not thermally deformed.

When the label of the present invention is peeled from the container,
The adhesive does not adhere to the container. If the adhesive adheres to the container, the container and label must be removed in the recycling process, and the adhesive attached to the container must be removed.
It is very troublesome and not preferable.

FIG. 1 shows a state in which the label of the present invention is applied to a container by heating. A heat-sensitive adhesive label 2 is wound around a container 1, and a heat-sensitive adhesive layer is attached to the container at a portion 4 of the label, and a heat-sensitive adhesive is applied at a portion 3 of the label (a portion where the front end and the rear end of the label overlap). The adhesive layer is affixed to the surface of the label, that is, the non-laminated surface of the plastic film.

The peel strength between the label and the container is preferably 5
１００100 g / 25 mm, the peel strength between the label back surface and the label front surface (portion 3 shown in FIG. 1) is preferably 100 g.
/ 25 mm and desirably 500 g / 25 mm or less. When the peel strength of each part is in such a range,
The label does not shift or peel off at the distribution stage of the container (product), and the label can be easily peeled off from the container in the recycling process.

When a printing ink layer is provided between the plastic film and the heat-sensitive adhesive layer, the label becomes more significant. Because, printing of the display of the product name and contents,
This is because the design can be imparted to differentiate the product from other companies' products. The printing ink layer may be the entire surface of the plastic film or may be partial. As the printing ink to be used, a known ink containing a plastic film to be used and a binder to be applied (for example, polyurethane, chlorinated polypropylene, or polyamide) may be used.

Further, depending on the type of the contents, there is a case in which after the contents are filled in a container, a sterilizing treatment step called a normal paste is performed, in which the container is showered with 70 ° C. hot water for 15 minutes to 30 minutes. After this step, it is more preferable that the printing ink used for printing between the plastic film and the heat-sensitive adhesive layer does not contain wax. If the printing ink component contains wax, the peel strength between the heat-sensitive adhesive layer and the printing ink layer is smaller than the peel strength between the heat-sensitive adhesive layer and the container,
At the time of label peeling, the heat-sensitive adhesive layer adheres to the container, and the adhesive tends to mix in the container regeneration step. in this case,
Since it is necessary to remove the adhesive adhered to the container, it takes much time and is not preferable.

In general, the wax contained in the printing ink is not particularly limited, but may be polyethylene wax, polypropylene wax, ethylene tetrafluoride, fatty acid amide,
Examples include paraffin wax, fatty acids and fatty acid esters, higher aliphatic alcohols, metal soaps and the like. That is,
It is more preferable that the printing ink used for printing applied to the label of the container that has undergone the pastelizing treatment does not contain these waxes.

Further, the heat-sensitive adhesive label of the present invention has a structure in which the pressure-sensitive adhesive is laminated not on the entire surface of the plastic film (label) but on a part thereof. , Because there is a gap between the container and the label,
If a container (product) is exposed to a hot water shower during the pastelizing process, not only will the hot water permeate between the container and the label and the appearance will deteriorate, but also the peeling strength between the container and the label will decrease. Problems such as the label being easily displaced from the container occur.

The plastic film on which the pressure-sensitive adhesive layer is laminated is not particularly limited, and examples thereof include stretched and non-stretched films made of various resins such as polyethylene, nylon, polystyrene, polypropylene, and polyester. Among these, transparency, gloss,
From the viewpoint of appropriate waist and the like, biaxially oriented polypropylene and biaxially oriented polyester film are particularly preferable. In the case where the container is made of polyester and the plastic film is made of biaxially stretched polyethylene terephthalate, even if both are made of the same polyester, their properties are different.

The heat-sensitive adhesive of the present invention has a blocking degree of 50 g / 25 mm or less and a heating temperature of 60 to 1
There is no particular limitation as long as the pressure-sensitive adhesive does not adhere to the container when peeled from the container after heating at 20 ° C., for example, polybutadiene, polyisobrene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate Copolymers and the like can be exemplified.

Among these, depending on the thickness of the adhesive,
The peel strength with the label surface, and the peel strength with the container are easy to control, and furthermore, because there is little odor,
Especially, an ethylene-vinyl acetate copolymer is preferable.
More preferably, the ethylene-vinyl acetate copolymer has a vinyl acetate content of 25 to 35 mol% and a melt index of 5 to 200.

When the content of vinyl acetate is less than 25%,
Regardless of the value of the melt index, the peel strength with the container after heat application is less than 5 g / 25 mm, the peel strength with the label surface is easily 100 g / 25 mm or less, and the adhesive strength to the label surface and the container is low. Since it is not sufficient, there is a possibility that peeling from the label surface or falling off from the container may occur, and the function as a label tends to be insufficient and unfavorable.

When the vinyl acetate content exceeds 35 mol%, the blocking degree exceeds 50 g / 25 mm regardless of the value of the melt index. for that reason,
When the label is stored in a roll state, blocking on the adhesive non-laminated surface is likely to occur, making it extremely difficult to unwind.Therefore, it is necessary to store the label at a low temperature or place a release paper on the adhesive surface. come. Furthermore, since the peel strength from the container after heating and pasting at 60 to 120 ° C. exceeds 100 g / 25 mm, peeling from the container after use becomes difficult, and the adhesive or printing ink tends to remain on the container, which is not preferable. is there.

On the other hand, when the content of vinyl acetate is 25 to 35 mol% and the melt index is more than 200 or less than 5, the peel strength from the container after heating and sticking is 5%.
g / less than 25mm, peel strength from label surface is 100g
/ 25 mm or less, or the blocking degree is 50 g /
Since it exceeds 25 mm, the adjustment is difficult and unfavorable.

The method of laminating the pressure-sensitive adhesive layer on the entire surface of the plastic film in advance is not particularly limited, and may be a known method such as an extrusion method, various coating methods, and various printing methods. (However, those that require high-temperature heating in air, such as the hot melt method, should be avoided for the above-mentioned reasons.)

In particular, a method using gravure printing is preferable. The reason is as follows. That is, since it is common for letters and designs to be gravure printed on a label, if a gravure printing method is used to laminate the heat-sensitive adhesive,
This is because a heat-sensitive adhesive can be applied to a gravure printing machine following printing of characters and patterns, which is extremely efficient. Further, by appropriately selecting the mesh and the depth of the gravure plate, a heat-sensitive adhesive layer having a desired thickness can be accurately obtained.

When the label is peeled from the container, the pressure-sensitive adhesive is prevented from adhering to the container (specifically, the peel strength between the label and the container is 5 to 100 g / 25 mm, and the label back surface and the label front surface (see FIG. (3 part indicated by 1) Peel strength is 10
More than 0 g / 25 mm and 500 g / 25 mm or less. For this reason, in one cut label, the thickness of the pressure-sensitive adhesive layer is formed thick at the leading end portion and the trailing end portion of the label, that is, at the portion where the label back surface and the surface overlap, and thin at the portion wound around the container. Is also one preferred form. More preferably, at the portion where the back surface and the front surface of the label overlap, it is more preferable that the pressure-sensitive adhesive layer at the rear end portion attached to the surface of the label be thicker than at the front end portion attached to the container. This means that the peeling strength of the part to be affixed to the container is such that the pressure-sensitive adhesive layer does not remain on the container at the time of recycling, and it is sufficient that the displacement does not occur due to the tension at the time of label winding, This is because the peel strength of the part to be affixed to the surface of the label is preferably higher than that of the part to be affixed to the container because the label must be held on the container.

[0034]

EXAMPLES Next, typical examples of the present invention will be described. The methods for measuring and evaluating the physical properties used in the present invention are as follows.

(Degree of blocking) Ten pieces of labels cut to 10 cm × 10 cm are overlapped so that the adhesive-laminated surface and the non-adhesive-laminated surface are overlapped, and 100 g of the label is further placed thereon.
/ Cm ² under a 40 ° C dry environment.
Stored for 4 hours. After that, under the environment of 23 ° C, JI was used with Shinto Kagaku Co., Ltd. T-type peel tester HEIDON-17.
The peel strength was measured based on the measuring method described in SP8139. As an evaluation 1, the peel strength was 50 g / 25.
mm or less was regarded as good.

(Peel strength from label surface) 25 mm × 1
The two labels cut to 00 mm are overlapped so that the adhesive-laminated surface and the non-adhesive-laminated surface (that is, the label surface) are overlapped, and a load of 100 g / cm ² is applied thereon, and the environment is dried at 80 ° C. Stored below for 5 minutes. Thereafter, the peel strength was measured using a T-type peel tester HEIDON-17 manufactured by Shinto Kagaku Co., Ltd. in an environment of 23 ° C. based on the measuring method described in JIS P8139. As an evaluation 2, the peel strength exceeds 100 g / 25 mm, and
Those with 0 g / 25 mm or less were regarded as good.

(Peel strength with container) 25 mm × 100 m
The label cut to m was superimposed on a polyethylene terephthalate sheet so that the pressure-sensitive adhesive laminated surface was in contact therewith, a load of 100 g / cm ² was applied thereon, and the label was stored for 5 minutes in an environment of 80 ° C. dry. Then, under the environment of 23 ° C, Shinto Kagaku Co., Ltd. T-type peel tester HEIDON-
17, the peel strength was measured based on the measuring method described in JISP8139. As the evaluation 3, the peel strength was
Those with 5 to 100 g / 25 mm were regarded as good.

(Removability after Paste Rise) 25 mm × 10
The label cut to 0 mm is superimposed on the polyethylene terephthalate sheet so that the adhesive laminated surface is in contact with the label,
Further, a load of 100 g / cm ² is placed on the
Stored in a dry environment for 5 minutes. Next, 70 ° C. hot water was showered on the sample for 20 minutes. Then 2
T-peel tester H manufactured by Shinto Kagaku Co., Ltd. under 3 ℃ environment
A peel test was performed on EIDON-17 based on the measurement method described in JIS P8139. As the evaluation 4, the one in which the adhesive was not left on the container was evaluated as good.

Example 1 A printing layer (5 colors) and a heat-sensitive adhesive layer were formed on a biaxially stretched polypropylene film having a thickness of 50 μm by gravure printing using a printing ink containing no wax. At this time, the heat-sensitive adhesive layer had a vinyl acetate content of 30 mol% and a melt index of 60.
The vinyl acetate copolymer was dissolved in toluene at a concentration of 10% by weight, formed into a gravure plate whose depth was adjusted so that the coating thickness after drying was 7 μm, and dried.

Example 2 A printing layer (5 colors) and a heat-sensitive adhesive layer were formed by gravure printing with a printing ink containing no wax on a biaxially stretched polypropylene film having a thickness of 50 μm. In this case, the heat-sensitive adhesive layer was prepared by dissolving an ethylene-vinyl acetate copolymer having a vinyl acetate content of 25 mol% and a melt index of 150 in toluene at a concentration of 10% by weight, and drying after drying in one label pattern. Adjust the depth so that the coating thickness of the label is 10 mm wide at both ends where the label overlaps, 7 μm at the end to be affixed to the container, 10 μm at the end to be affixed to the surface of the label, and 3 μm at the part wound around the container. A gravure plate was formed and dried.

Comparative Example 1 The procedure of Example 1 was repeated except that an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 mol% and a melt index of 2 was used as the heat-sensitive adhesive.

Comparative Example 2 Example 1 was repeated except that an ethylene-vinyl acetate copolymer having a vinyl acetate content of 43 mol% and a melt index of 350 was used as the heat-sensitive adhesive.
Prepared as in

The evaluation results from Example 1 to Comparative Example 2 are summarized in Table 1.

(Table 1)

[0045]

Since the present invention has the above configuration, the following effects can be obtained.

The heat-sensitive adhesive label of the present invention is a label suitable for containers to be recycled because the adhesive does not adhere to the container when peeled from the container.

Since the degree of blocking is 50 g / 25 mm or less, even when stored for a long time in summer, it can be smoothly unwound when used.

The heating temperature for winding and sticking on the container is 60
Since the temperature is as low as ~ 120 ° C, the pressure-sensitive adhesive does not thermally decompose to generate an odor or the film is not thermally deformed.

Since the pressure-sensitive adhesive is laminated on the entire surface of the plastic film, hot water at the time of pastries and dew condensation generated when the container (product) is removed from the refrigerated showcase do not enter between the label and the container. .

When a gravure printing method is employed as a method for laminating the pressure-sensitive adhesive layer on the plastic film, the thickness can be accurately and efficiently produced. Further, it is easy to partially change the thickness of the pressure-sensitive adhesive layer.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a heat-sensitive adhesive label according to the present invention is applied by heating.

FIG. 2 is a sectional view of a heat-sensitive adhesive label according to Example 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Heat-sensitive adhesive label 3 Label both ends overlapping part 4 Adhesion part with a container 5 Heat-sensitive adhesive layer 6 Printing ink layer 7 Plastic film

Claims (8)

[Claims] 1. A heat-sensitive adhesive label which is heated and wound around the entire circumference of a container, wherein the blocking degree is 50 g / 25.
mm or less is preliminarily laminated on the entire surface of the label, and after heating and sticking at a heating temperature of 60 to 120 ° C., when peeled from the container, the adhesive does not adhere to the container. Heat-sensitive adhesive label. 2. The heat-sensitive adhesive label according to claim 1, wherein a printing ink layer is provided between the plastic film and the heat-sensitive adhesive layer. 3. The heat-sensitive adhesive label according to claim 1, wherein the pressure-sensitive adhesive layer does not adhere to the container when peeled from the container after the pastelizing treatment. 4. The container material comprises one selected from the group consisting of polyester, glass and paper, and the plastic film is a biaxially oriented polypropylene film or a biaxially oriented polyester film.
The heat-sensitive adhesive label according to any one of the above items. 5. The pressure-sensitive adhesive layer having a vinyl acetate content of 25 to 35.
5. A layer mainly composed of an ethylene-vinyl acetate copolymer having a mol% of 5 to 200 and a melt index of 5 to 200.
The heat-sensitive adhesive label according to any one of the above items. 6. The heat-sensitive adhesive label according to claim 1, wherein the adhesive layer is a layer formed by gravure printing. 7. The cut one label, wherein the thickness of the pressure-sensitive adhesive layer is thick at a portion where the back surface and the front surface of the label overlap, and thin at a portion wound around the container. The heat-sensitive adhesive label according to any one of the above items. 8. A container to which the heat-sensitive adhesive label according to claim 1 is attached.