JP2003036030A - Thermal adhesive label with no remaining paste and bottle using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label favorable for a bottle to be recycled as it can be unrolled smoothly when used even after being kept for a long time in summer, it can be rolled and attached to the bottle by using high-speed automatic label attaching machine at the label attaching temperature of 80 to 120 deg.C, and it leaves no adhesive onto the bottle when being exfoliated from the bottle. SOLUTION: This is a heat sensitive adhesive label whose substrate is a plastic film which is heated and rolled and attached to the whole circumference of the bottle. Ethylene-vinyl acetate copolymer 85 to 99 weight % whose vinyl acetate content is 25 to 35 mol% and whose melt index is 5 to 200, and heat sensitive adhesion agent layer which consists of low molecular hydrocarbon resin 15 to 1 weight % are laminated on the plastic film characteristically.

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 stuck on the entire circumference of the container surface, particularly suitable for a container to be recycled, and exhibits adhesiveness in a short time. The present invention relates to a heat-sensitive adhesive label that has a heat-sensitive adhesive layer that does not transfer the adhesive to a container when peeled.

[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 to recycle used containers has become established. Various types of containers, such as glass bottles, PET bottles, and paper packs, are usually provided with various types of labels from the viewpoints of container damage protection, display of contents, and design. Since these are preferably those that can be easily separated from the container at the time of recycling, various suitable labels and containers with the label attached thereto have been proposed. For example,
In Japanese Patent Laid-Open No. 4-279454, a rectangular label made of a printed plastic film is wrapped around the outer circumference of a plastic bottle, and the front end portion of the back surface of the label is wrapped around the bottle surface and the rear end portion thereof is wrapped around. Disclosed is a plastic bottle characterized in that 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, which are adhered to the surface of the label with a hot melt agent. Further, the present inventor has also conducted research on a heat-sensitive adhesive label in which an adhesive does not adhere to a container, as disclosed in Japanese Patent Laid-Open No. 2001-42775.

[0003]

However, in the case of the invention described in Japanese Patent Laid-Open No. 4-279454, the hot-melting agent is melted at a high temperature of 150 to 200 ° C. in the air, that is, in the presence of oxygen. Because it is used (generally, hot melt agents are used at such temperatures), a strange 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 hot There are problems such as preparation before starting the melt agent application operation and cleaning the application apparatus including the hot melt agent application roller after the operation is time-consuming. In addition, Japanese Patent Laid-Open No. 2001-42
In the case of the invention described in Japanese Patent No. 775, although the above-mentioned problems have been solved, it takes time to develop the adhesiveness of the heat-sensitive adhesive layer, and therefore, further improvement has been demanded for mounting with a high-speed automatic label mounting machine.

The first problem to be solved by the present invention is
It is to provide a suitable heat-sensitive adhesive label by recycling. A second problem is to provide a heat-sensitive adhesive label that can be attached by a high-speed automatic label attaching machine. The third problem is to provide a container suitable for recycling.

[0005]

[Means for Solving the Problems] As a means for solving the above problems, the present invention provides a heat-sensitive adhesive label comprising a plastic film as a base, which is heated and wound around the entire circumference of a container. Vinyl acetate content 25-35 mol% and melt index 5-200
Is a heat-sensitive adhesive label in which a heat-sensitive adhesive layer comprising 85 to 99% by weight of the ethylene-vinyl acetate copolymer and 15 to 1% by weight of a low molecular weight hydrocarbon resin is laminated.

[0006] It is characterized in that it is a container to which the heat-sensitive adhesive label is attached.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION 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 substrate 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 the long label wound in a roll is unwound, and the heat-sensitive adhesive layer having adhesiveness is moved from the front end portion to the rear end portion of the label. Wrap and paste it on the container. The rear end portion of the label obtained by winding the container around the label is overlapped with the front end portion of the label, and the label is cut into a predetermined size.

FIG. 1 shows a state diagram in which the label of the present invention is heat stuck on a container. The heat-sensitive adhesive label 2 is wound around the container 1, the heat-sensitive adhesive layer is attached to the container at the portion 4 of the label, and heat-sensitive at the portion 3 of the label (the portion where the leading end portion and the rear end portion of the label overlap). The adhesive layer is attached to the surface of the label, that is, the surface of the plastic film substrate on which the adhesive is not laminated.

The label of the present invention, when peeled from the container,
The feature is that the adhesive does not transfer to the container. Furthermore,
The feature is that labels can be attached without problems even at high speeds of 300-500 bpm high-speed automatic label attaching machines. When the adhesive is transferred to the container, the adhesive must be removed after peeling the container and the label in the recycling process, which is very time-consuming, and the label can only be attached at a low speed in the summer. It is not preferable because it cannot cope with an increase in the supply amount.

The heat-sensitive adhesive label of the present invention is a label which is laminated on a plastic film base in advance with an adhesive which is not adhesive at room temperature but develops adhesiveness when heated. The plastic film substrate on which the adhesive is laminated is not particularly limited, and examples thereof include stretched and non-stretched films made of various resins such as polyethylene, polyamide, polystyrene, polypropylene and polyester. Among these, transparency, gloss,
In particular, biaxially oriented polypropylene is preferable from the viewpoint of proper waist.

The heat-sensitive adhesive of the present invention has a vinyl acetate content of 25 to 35 mol% and a melt index of 5 to 20.
It is preferable to use 85 to 99% by weight of an ethylene-vinyl acetate copolymer of 0 and 15 to 1% by weight of a low molecular weight hydrocarbon resin. The ethylene-vinyl acetate copolymer is preferable in that the peel strength with the label surface and the peel strength with the container can be easily controlled by the thickness of the pressure-sensitive adhesive, and further, the odor is small.

When the content of vinyl acetate is less than 25%,
Even if the melt index is within the appropriate range, the label surface and the container may not be sufficiently adhered, so that peeling from the label surface or dropping from the container may occur, resulting in insufficient label function. Is not preferable.
When the content of vinyl acetate exceeds 35 mol%, even if the melt index is within the above-mentioned appropriate range, blocking on the pressure-sensitive adhesive non-laminated surface is likely to occur when the label is stored in a roll state, which may cause unwinding. Since it becomes extremely difficult, it becomes necessary to store it at a low temperature or place a release paper on the adhesive surface. Furthermore, the adhesive or printing ink remains untouched on the container after heating and pasting, which is not preferable.

On the other hand, when the content of vinyl acetate is 25 to 35 mol% and the melt index is more than 200, the peel strength with the container after heat sticking and the peel strength with the label surface are weakened. Adjustment is difficult and not preferable. If the melt index is less than 5, blocking of the pressure-sensitive adhesive non-laminated surface tends to occur when the label is stored in a roll state.

The low molecular weight hydrocarbon resin of the present invention is typically rosin, rosin derivative, terpene resin, terpene phenol resin, aromatic modified terpene resin, hydrogenated terpene resin, hydrocarbon resin (aliphatic resin). System hydrocarbon resin, aromatic hydrocarbon resin, copolymerization hydrocarbon resin, alicyclic hydrocarbon resin) and the like. Among these, hydrocarbon resins are particularly preferable from the viewpoints of easy handling and easy adjustment of the tackiness developing rate. Among the hydrocarbon resins, the softening point is more preferably 9
Those having a temperature of 0 ° C. or higher and a number average molecular weight of 800 or higher are preferable. This is because when the softening point is less than 90 ° C. or the number average molecular weight is less than 800, the adhesive agent is transferred when the label is peeled from the container, which is not preferable.

The addition amount of the low molecular weight hydrocarbon resin is preferably 1 to 15% by weight of the adhesive. 1% by weight
If it is less than the range, it takes a long time to develop the adhesiveness of the pressure-sensitive adhesive, so that there is a tendency that the label cannot be attached by the high-speed automatic label attaching machine. On the other hand, when the amount added exceeds 15% by weight, the roll label tends to be blocked because the roll label develops adhesiveness even during storage. By adding a low molecular weight hydrocarbon resin to the pressure-sensitive adhesive, it is possible to accelerate the development of the pressure-sensitive adhesive property of the pressure-sensitive adhesive, that is, to enable label mounting with a high-speed automatic label mounting machine and maintain high productivity. Have.

The thickness of the pressure-sensitive adhesive layer to be laminated on the plastic film is not particularly limited as long as it has the properties of the present invention, but is usually 1 to 50 μm, preferably 2
˜30 μm, and more preferably 3 to 15 μm. The method for laminating the pressure-sensitive adhesive layer on the plastic film is not particularly limited, and known methods such as an extrusion method, various coating methods and various printing methods may be used. (However, it is better to avoid the hot melt method in which high temperature heating in air is indispensable for the above reason.) Especially, the method by gravure printing is preferable. The reason is as follows. That is, since it is common for characters and patterns to be gravure printed on the label, if the gravure printing method is used to stack the heat-sensitive adhesive layer, the characters and patterns can be printed by one gravure printing machine. This is because the heat-sensitive adhesive can be applied subsequent to printing, which is extremely efficient. Furthermore, by appropriately selecting the mesh and plate depth of the gravure plate, a heat-sensitive adhesive layer having a desired thickness can be accurately obtained.

Further, when the label is peeled from the container, it is cut to prevent the adhesive from transferring to the container.
In one preferred form, the thickness of the pressure-sensitive adhesive layer in the label of one sheet is thick at the front end portion and the rear end portion of the label, that is, the portion where the back surface of the label and the front surface overlap and is thin at the portion wound around the container. is there. More preferably, in the portion where the back surface and the front surface of the label overlap, it is preferable that the pressure-sensitive adhesive layer at the rear end portion attached to the surface of the label is thicker than the front end portion where the label is attached to the container. The peel strength of the portion attached to the container may be such that the pressure-sensitive adhesive layer does not remain on the container at the time of recycling and the tension at the time of label winding does not cause displacement, but on the other hand, This is because the peel strength of the portion attached to the surface of the label is preferably larger than that of the portion attached to the container because the label must be held on the container.

Providing a printing ink layer between the plastic film substrate and the heat-sensitive adhesive layer provides a more significant label. This is because it is possible to print the display of the product name and the contents, and to add the design property for differentiating the product from other companies of the same kind. The printing ink layer may be the entire surface of the plastic film or a partial surface thereof. The printing ink used may be a known ink containing a plastic film substrate to be used and a binder to be applied (for example, polyurethane type, chlorinated polypropylene type, polyamide type, etc.).

When the label of the present invention is applied by winding around the entire circumference of the container, the label of 80 to 120 is provided on the heat-sensitive adhesive layer side immediately before application.
° C, preferably 90-120 ° C, more preferably 95-
Since the adhesiveness is developed by blowing hot air of 120 ° C. for 0.5 seconds, the label is not thermally deformed,
Suitable for high-speed automatic label loading machine.

[0022]

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.

(Blocking Degree) 10 labels cut into 10 cm × 10 cm are stacked so that the pressure-sensitive adhesive laminated surface and the pressure-sensitive adhesive non-laminated surface overlap each other, and 100 g on top of that.
/ Cm ² was applied and the product was stored in a dry environment at 40 ° C for 24 hours. After that, in a 23 ° C. environment, using a T-type peel tester HEIDON-17 manufactured by Shinto Scientific Co., Ltd., JIS P
The peel strength was measured based on the measuring method described in 8139. As evaluation 1, this peel strength is 0.5 N / 25 mm
The following were considered good.

(Peel strength from label surface) 15 mm × 1
Two labels cut out to 00 mm are overlapped so that the pressure-sensitive adhesive laminated surface and the pressure-sensitive adhesive non-laminated surface (that is, the label surface) overlap each other, and the temperature is 80 ° C., the time is 0.5 seconds, and the pressure is 60 k.
Adhesion was performed using a heat sealer manufactured by Toyo Seiki Co., Ltd. with a surface area of 10 × 25 mm, and a P-tester HEIDON-17 manufactured by Shinto Kagaku Co., Ltd. under the environment of 23 ° C. to JIS P8.
The peel strength was measured based on the measuring method described in 139. As evaluation 2, those having a peel strength of more than 1 N / 15 mm and 5 N / 15 mm or less were evaluated as good.

(Peeling strength from container) 15 mm × 100 m
The pressure-sensitive adhesive laminated surface of the label cut out in m and the polyethylene terephthalate sheet were laminated so that the pressure-sensitive adhesive laminated surface was in contact, and the temperature was 100 ° C., the time was 0.5 seconds, and the pressure was 6
Bonded with a heat sealer manufactured by Toyo Seiki Co., Ltd. at 0 kPa, area = 10 × 25 mm, and in a 23 ° C. environment using a T-type peel tester HEIDON-17 manufactured by Shinto Kagaku Co., Ltd. JIS
The peel strength was measured based on the measuring method described in P8139. As the evaluation 3, the peel strength is 0.01 to 1N.
/ 15 mm was considered good.

Example 1 A printing layer (1) was formed by gravure printing on a biaxially oriented polypropylene film having a thickness of 50 μm.
Color) and a heat-sensitive adhesive layer were formed. At this time, the heat-sensitive adhesive layer was obtained by adding an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30 mol% and a melt index of 60 to an aliphatic hydrocarbon resin (softening point 1 as a low molecular weight hydrocarbon resin.
100 ° C, molecular weight 1200) was added at 10% by weight to give a concentration of 1
Dissolved in toluene at 5% by weight, coating thickness after drying is 7 μm
It was formed with a gravure plate whose depth was adjusted so that

Example 2 A print layer (one color) and a heat-sensitive adhesive layer were formed by gravure printing on a biaxially stretched polyethylene terephthalate film having a thickness of 50 μm. In this case, the heat-sensitive adhesive layer is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 25 mol% and a melt index of 150 and an aliphatic hydrocarbon resin (softening point 100 ° C., molecular weight as a low molecular weight hydrocarbon resin. 1200) in an amount of 10 wt% and dissolved in toluene at a concentration of 15 wt% to give 1
In the design of one label, the coating thickness after drying is 10 mm width at both ends where the labels overlap each other, the side to be attached to the container is 7 μm, and the side to be attached to the surface of the label is 10 μm.
m, the portion wound around the container was formed with a gravure plate whose depth was adjusted to 3 μm, and dried.

Example 3 As a low molecular weight hydrocarbon resin, a terpene resin (softening point 120 ° C., molecular weight 1200)
Was prepared in the same manner as in Example 1 except that was used.

(Comparative Example 1) The same procedure as in Example 1 was carried out 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.

Comparative Example 3 An aliphatic hydrocarbon resin (softening point 80 ° C., molecular weight 800) as a low molecular weight hydrocarbon resin.
Was prepared in the same manner as in Example 1 except that 20% was added.

The evaluation results from Example 1 to Comparative Example 3 are summarized in Table 1.

(Table 1)

[0034]

Since the present invention has the above-mentioned structure, it has the following effects.

The heat-sensitive adhesive label of the present invention is a label suitable for a container to be recycled because the adhesive does not transfer to the container when peeled from the container. Since it does not block, it can be smoothly unwound when used even during long-term storage in the summer. Since the adhesiveness of the label for sticking on the container is high, it is suitable for label mounting by a high-speed automatic label mounting machine. Since the heat-sensitive adhesive layer is formed at room temperature, there is no offensive odor or heat deformation of the plastic film due to high temperature.

When the gravure printing method is adopted as a method for laminating the pressure-sensitive adhesive layer on the plastic film, the thickness accuracy is good and the production can be performed efficiently. Furthermore, it is easy to partially change the thickness of the adhesive layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a heat-sensitive adhesive label of Example 2 of the present invention.

FIG. 2 is a state diagram in which a heat-sensitive adhesive label according to the present invention is heat-bonded.

[Explanation of symbols]

1 container 2 Heat-sensitive adhesive label 3 Label both ends overlapped part 4 Sticking part with container 5 Thermosensitive adhesive layer 6 Printing ink layer 7 Plastic film substrate

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3E095 AA07 BA02 DA55 DA59                 4J004 AA07 AA09 AB01                 4J040 BA172 BA202 DA051 JB01                       KA31 LA08 LA11 MA10 MB03                       NA06 PA30

Claims (2)

[Claims] 1. A heat-sensitive adhesive label comprising a plastic film as a base material, which is heated and wound around the entire circumference of a container to have a vinyl acetate content of 25 on the plastic film.
A heat-sensitive adhesive layer composed of 85 to 99% by weight of an ethylene-vinyl acetate copolymer having a melt index of 5 to 200 and a low molecular weight hydrocarbon resin of 15 to 1% by weight. A heat-sensitive adhesive label that does. 2. A container to which the heat-sensitive adhesive label according to claim 1 is attached.