JPH07244462A - Heat sensitive adhesive label - Google Patents

Abstract

PURPOSE:To obtain a heat sensitive adhesive label ensuring easy sticking work and simple storage by forming an adhesive layer exhibiting adhesive property when heated and reducing its adhesive strength under an alkaline aq. soln., on the rear side of a substrate with a formed printed layer. CONSTITUTION:An adhesive layer 2 is formed on the entire rear side of a substrate 1. An adhesive used in the adhesive layer 2 is a delayed tack adhesive which does not exhibit adhesive property at an ordinary temp. but is activated at 50-150 deg.C, preferably 60-100 deg.C to exhibit tackiness and retains this tackiness for several hr to several days. When the adhesive comes in contact with an alkaline aq. soln., the adhesive strength is reduced by dissolution. The resultant heat sensitive adhesive label ensures easy sticking work, does not require releasing paper, etc., because of no adhesive property at an ordinary temp. and can be compactly stored. The label is easily peeled off by washing with the alkaline aq. soln. at >=60 deg.C.

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 attached to a container such as a beer bottle which is collected and reused after use and which can be easily peeled off when the container is washed.

[0002]

2. Description of the Related Art Conventionally, containers such as beer bottles which are collected after use, washed, and reused can be easily peeled off during washing as shown in Utility Model Publication No. 8615 of 1993. A different label was attached. Such a label is a label in which an aluminum vapor deposition layer 5 and a printing layer 7 are provided on a base material 1 having an adhesive layer 2 whose adhesive strength is reduced by an alkaline aqueous solution as shown in FIG. By dipping the bottle in an alkaline aqueous solution to reduce the adhesive strength of the label, the label can be peeled off from the bottle or the like.

[Problems to be Solved by the Invention]

However, when sticking such a label to a beer bottle or the like, it is necessary to control the amount of adhesive applied and the viscosity while sticking, and the sticking work is complicated.

When the label is coated with a pressure sensitive adhesive as an adhesive in advance, it is necessary to provide a release paper 10 on the upper surface of the adhesive layer 2, which is bulky during storage and is attached to the container 9. However, the sticking work must be performed while peeling off the release paper 10, and since the release paper 10 is provided, the cost is high.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat-sensitive adhesive label which can be easily attached and stored easily.

[0006]

Means for Solving the Problem The present invention has been made as a means for solving such a problem. As a means for solving the above problems, the back surface of a substrate 1 provided with a printing layer 3 is heated to provide adhesiveness, and This is because the adhesive layer 2 whose adhesive strength is reduced by the alkaline aqueous solution is provided.

[0007]

In other words, when an adhesive which does not exhibit adhesiveness at room temperature as described above but exhibits adhesiveness when heated is used, it is possible to apply the adhesive to the label in advance and store it at room temperature. Moreover, since it does not have adhesiveness at room temperature, release paper is unnecessary.

Further, since the adhesive is softened and activated by heating the label to produce adhesiveness, the label can be attached to a container such as a bottle without performing an operation of applying the adhesive. .

Further, since the adhesive strength of the adhesive is lowered by the alkaline aqueous solution, when the label is soaked in a bottle or the like and the label is immersed in the alkaline aqueous solution, the adhesive strength of the label is lowered and the adhesive is easily peeled off from the bottle or the like. can do. Further, when immersed in a high temperature alkaline aqueous solution, the adhesive softens due to heat, so that the label can be peeled off more easily.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure of the heat-sensitive adhesive label of the present invention will be described. In FIG. 1, reference numeral 1 is a base material made of a paper sheet having a predetermined shape, and an adhesive layer 2 is provided on the entire back surface of the base material 1.

Further, an aluminum vapor deposition layer 5 is provided on the surface of the substrate 1 via an undercoat layer 4, and a printing layer 3 and an overcoat layer 7 are provided on the surface of the aluminum vapor deposition layer 5 via a primer layer 6. The heat-sensitive adhesive label body 8 is provided with
Are formed.

The adhesive used for the adhesive layer 2 does not exhibit adhesiveness at room temperature, but it is activated and becomes tacky at a temperature of 50 ° C. to 150 ° C., preferably 60 ° C. to 100 ° C. It is a delayed tack adhesive that occurs and the tackiness lasts for hours to days.

Further, the adhesive has the property of being dissolved when it comes into contact with an alkaline aqueous solution to lower the adhesive strength.

The adhesive having such properties contains an alkali-soluble resin, a solid plasticizer, and a tackifier, and examples of the alkali-soluble resin include methyl acrylate, ethyl acrylate and acrylic acid. -Isopropylene, isobutyl acrylate, n-butyl acrylate,
Amyl acrylate, hexyl acrylate, acrylic acid 2
-Acrylic acid esters such as ethylhexyl, or methacrylic acid esters such as methyl methacrylate, butyl methacrylate, and hexyl methacrylate, or the above acrylic acid esters and methacrylic acid esters, and unsaturated acids such as acrylic acid and maleic acid Acrylic ester copolymers such as a copolymer resin made of a carboxylic acid are preferably alkali-soluble, excellent in compatibility with a plasticizer, and excellent in adhesiveness. Particularly, among such alkali-soluble resins, a self-crosslinking acrylic ester copolymer is preferable. The polymer is suitable for the heat-sensitive adhesive label of the present invention because it has a property of improving water resistance when heated.

It is also possible to use a mixture of a resin compatible with the alkali-soluble resin, for example, a mixture of an acrylic acid ester copolymer and a styrene / acrylic resin uniformly.

Further, as the solid plasticizer of the adhesive, the melting point of diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, dimethyl isophthalate, sucrose benzoate, ethylene glycol dibenzoate, tricyclohexyl citrate, etc. is 50. Those at about ° C to 100 ° C can be preferably used. This melting point is, for example, 50 °
If it is lower than C, the adhesive may be activated during the storage of the label, and if it is 100 ° C. or higher, the efficiency for activating the adhesive becomes poor.

As the tackifier, a rosin derivative,
Petroleum resin, terpene resin and the like can be used.

The adhesive layer 2 made of such an adhesive is applied to the back surface of the substrate 1 in the state of an aqueous emulsion,
Obtained by drying.

Further, the undercoat layer 4 is made of synthetic resin or the like, and a smooth layer can be formed on the surface of the base material 1 to facilitate the vapor deposition of the aluminum vapor deposition layer 5.

The aluminum vapor-deposited layer 5 is for imparting a metallic luster to the label by vapor-depositing aluminum on the substrate 1 provided with the undercoat layer 4.
Printing layer 3 with appropriate printing on the upper surface of the product
Is formed through a primer layer 6 provided to enhance the adhesiveness of the printed layer 3, and the surface of the printed layer 3 is transparent to protect the surfaces of the printed layer 3 and the aluminum vapor deposition layer 5. An overcoat layer 7 made of a different synthetic resin is provided.

Next, the case where the heat-sensitive adhesive label body 8 having such a structure is used for a container such as a beer bottle 9 will be described. First, when the label body 8 having the above-described structure is attached, the heat-sensitive adhesive label body 8 is heated by radiant heat such as hot air or infrared rays. At this time, the adhesive of the adhesive layer 2 is heated, and the solid plasticizer is melted and softened to be activated, thereby producing tackiness, and the adhesive causes the heat-sensitive adhesive label main body 8 to move to a position shown in FIG. B)
As shown in, it is attached to the body of the beer bottle 9.

Furthermore, when the heat-sensitive adhesive label body 8 is peeled from the beer bottle 9 collected after use, the beer bottle 9 is peeled off.
The above container is immersed in a 3% to 6% caustic soda aqueous solution 11 at a temperature of 60 ° C. and washed.

At this time, the alkali-soluble resin in the adhesive is dissolved by the caustic soda solution 11 and the adhesiveness of the adhesive layer 2 is lowered, so that the heat-sensitive adhesive label body 8 is peeled from the beer bottle 9.

Further, caustic soda solution 11 is added at 60 ° C.
Since the temperature is maintained at 1, the softening of the adhesive due to heat also occurs, so that the heat-sensitive adhesive label body 8 is easily peeled from the beer bottle 9.

Although the heat-sensitive adhesive label having the aluminum vapor-deposited layer 5 and the printed layer 3 is used in the above embodiment, both the aluminum vapor-deposited layer 5 and the printed layer 3 are formed on the heat-sensitive adhesive label body 8. Is not a condition, and only the printing layer 3 may be formed on the base material 1, for example.

The materials of the undercoat layer 4, the primer layer 6 and the overcoat layer 7 are not limited to those in the above embodiment, but when an alkali-soluble resin is used as the material, an alkaline aqueous solution is used. The releasability of the heat-sensitive adhesive label when dipped in is further enhanced.

Further, in the above embodiment, the heat-sensitive adhesive label having the undercoat layer 4, the primer layer 6 and the overcoat layer 7 is used, but a heat-sensitive adhesive label without these layers may be used.

Further, although the heat-sensitive adhesive label stuck to the beer bottle 9 has been described in the above-mentioned embodiment, the heat-sensitive adhesive label of the present invention may be a container made of glass, synthetic resin or the like which is washed and reused. It can be used in any container.

Further, in the above embodiment, the adhesive layer 2 is the base material 1.
The adhesive layer 2 may be partially provided on the back surface of the base material 1 in a stripe pattern or the like. In this case, there is an advantage that the alkaline aqueous solution easily penetrates into the adhesive and peeling can be facilitated.

Although the delayed tack adhesive is used as the heat-activatable adhesive in the above-mentioned embodiments, other adhesives such as hot-melt adhesives that are activated by heat to produce adhesiveness can be used. It can be used as layer 2.

Furthermore, in the above embodiment, the caustic soda solution 11 was used as the alkaline aqueous solution for peeling the heat-sensitive adhesive label, but other alkaline aqueous solution can be used as the peeling liquid for the heat-sensitive adhesive label of the present invention.

Although the base material 1 made of paper is used in the above embodiment, the material of the base material 1 is not limited to this, and a synthetic resin film such as polyester or polypropylene may be used. Good.

[0034]

As described above, since the heat-sensitive adhesive label of the present invention is coated with an adhesive which does not exhibit adhesiveness at room temperature and produces adhesiveness when heated, the label is attached to a bottle or the like. The adhesive can be pre-applied to the label prior to application. Therefore, it is not necessary to apply an adhesive at the time of attaching the heat-sensitive adhesive label to the container, and it becomes unnecessary to adjust the viscosity and the amount of the adhesive at the time of attaching as in the conventional case.
The effect that the attaching work can be easily performed is obtained.

Further, since it does not have adhesiveness at room temperature, a release paper or the like is not required when storing a heat-sensitive adhesive label coated with an adhesive, and it can be stored compactly, and a release paper is not required. Therefore, it is economical.

Further, when washing is performed using an alkaline aqueous solution having a temperature of 60 ° C. or higher, the softening of the adhesive by heating and the dissolution of the adhesive in the alkaline aqueous solution synergize with each other to further enhance the heat-sensitive adhesive label. It is also possible to obtain the effect of being easily peeled off.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a heat-sensitive adhesive label according to the present invention.

FIG. 2A is a front view in which a heat-sensitive adhesive label is attached to a beer bottle, and FIG. 2B is a cross-sectional view taken along the line AA.

FIG. 3 is an enlarged sectional view of a conventional heat-sensitive adhesive label.

[Explanation of symbols]

 1 ... Substrate 2 ... Adhesive layer 3 ... Printing layer 8 ... Heat-sensitive adhesive label 9 ... Beer bottle

Claims (5)

[Claims] 1. A heat-sensitive adhesive label comprising an adhesive layer (2) provided on the back surface of a base material (1) to produce adhesiveness when heated and whose adhesive strength is reduced by an alkaline aqueous solution. 2. The heat-sensitive adhesive label according to claim 1, wherein the base material (1) is made of paper. 3. The heat-sensitive adhesive label according to claim 1, wherein the base material (1) is vapor-deposited with aluminum. 4. The adhesive layer (2) according to claim 1, wherein the adhesive layer (2) is composed of an adhesive lasting heat-sensitive adhesive containing an acrylic ester copolymer and a solid plasticizer. The heat-sensitive adhesive label described. 5. The heat-sensitive adhesive label according to claim 1, wherein the adhesive layer (2) exhibits adhesiveness at a temperature of 50 ° C. or higher.