JPH07134553A - Label - Google Patents

Abstract

PURPOSE:To provide a label which can easily be peeled off concurrently at the time of alkali-washing by forming the label through coating the rear surface of the substrate of the label with a heat-sensitive adhesive contg. a material which can react with an alkaline solution to generate a gas. CONSTITUTION:The rear surface of the base material 1 of this label is coated with the heat-sensitive adhesive 2 contg. a material which can react with an alkaline solution to generate a gas. This label is used for labelling a bottle by heating it to activate the heat-sensitive adhesive 2 and then sticking it on the surface of a bottle such as a glass bottle, etc., with this heat-sensitive adhesive 2. When the emptied, labelled bottle is recovered and washed with an alkali-washing liquid, the above material in the heat sensitive adhesive 2 reacts with the alkaline solution in the alkali-washing liquid to generate a gas such as gaseous hydrogen, etc., and to form bubbles. At this time, since the heat- sensitive adhesive 2 is held between the substrate 1 of the label and the surface of the bottle, formation of a space between the base material 1 and the surface of the bottle and further, widening of the space can be effected by the action of the bubbles formed with the generated gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label which is used by being stuck on a glass bottle or other bottles.

[0002]

2. Description of the Related Art Bottles such as beer bottles and sake shochu are collected and repeatedly used. A label is attached to such a bottle in order to display the contents, and the label is peeled off when the bottle is collected and washed. For example, soak the bottles sequentially in multiple liquid tanks containing an alkaline cleaning solution to wash the bottles, dissolve the label adhesive with an alkali to remove the label, and then remove the label with a rotating brush etc. A bottle-washing machine designed to scrape off the label, or the alkaline cleaning solution is spouted from the nozzle in a shower shape to the outside or inside of the bottle to blow off the label, and then the label left on the surface of the bottle with a rotating brush. The label can be peeled off at the same time when the bottle is washed by using a bottle washing machine adapted to scrape off.

The conventional label is attached to the bottle by starch paste or the like coated on the back surface.
It is often practiced to use a label in which a heat-sensitive adhesive that is activated by heating is coated on the back surface of a base material, and to attach the label to a bottle with this heat-sensitive adhesive. Since the heat-sensitive adhesive does not show tackiness at room temperature, the label can be handled easily, and the adhesive can be activated and attached to the bottle by simply heating the label. This has the advantage that there is no need to provide an applicator for applying adhesive to the label.

[0004]

However, the heat-sensitive adhesive generally has higher resistance to an alkaline solution than starch paste and the like, and therefore the label is not easily peeled off when the bottle is washed with an alkaline washing solution, and the label is Even if it was peeled off, the adhesive remained in the bottle and remained attached, making it difficult to remove.

The present invention has been made in view of the above points, and provides a label that can be easily peeled from a bottle or the like by alkali cleaning and can be peeled without leaving an adhesive on the bottle or the like. The purpose is.

[0006]

The label according to the present invention comprises:
It is characterized in that the back surface of the base material 1 is coated with a heat-sensitive adhesive 2 containing a substance which reacts with an alkaline solution to generate a gas. In the present invention, alkali-soluble metal powder can be used as a substance that reacts with an alkaline solution to generate gas.

Further, in the present invention, it is preferable to use, as the heat-sensitive adhesive 2, one having a stronger adhesive force with respect to the base material 1 than with respect to an object to be labeled. Hereinafter, the present invention will be described in detail. The base material 1 of the label is formed of paper or the like, and the surface of the base material 1 is printed to provide a printing layer 5, and a coating layer 6 such as a varnish is further provided on the surface. By coating the back surface of the base material 1 with the heat-sensitive adhesive 2, a label having a layer structure as illustrated in FIG. 1 can be prepared.

This heat-sensitive adhesive (also called delayed tack adhesive) is an adhesive which is activated by heating. The heat-sensitive adhesive is mainly composed of a crystalline plasticizer and a tackifier, and it does not show tackiness at room temperature, but it is activated and sticks by heating above the melting temperature of the crystalline plasticizer. The property is that the adhesiveness is exhibited and the tackiness lasts for a long time. As this heat-sensitive adhesive, dicyclohexyl phthalate (DCHP)
Prepared by adding a lubricant, a stabilizer, etc. as a main component and a tackifier such as a styrene resin, a styrene butadiene resin, an acrylic resin, a rosin resin, etc. Any of those provided in JP-A-62-21835 and JP-A-1-96274 can be used.

In the present invention, the heat-sensitive adhesive is mixed with a substance which reacts with an alkaline solution such as sodium hydroxide to generate gas. As a substance that reacts with the alkaline solution to generate a gas, an alkali-soluble metal powder such as aluminum, zinc, lead or iron can be used. These metal powders react with each other while being dissolved in an alkaline solution to generate hydrogen gas. Among these metal powders, those having good mixing and dispersibility in the heat-sensitive adhesive, light specific gravity and high reactivity are preferable, and it is usually most preferable to use the aluminum powder. The mixing amount of these metal powders in the heat-sensitive adhesive is 2 to 2
A range of 0% by weight is preferred. If the amount is less than 2% by weight, it is difficult to sufficiently obtain the effect of peeling off the label by using the metal powder, and conversely, if the amount of the metal powder exceeds 20% by weight, the adhesive strength decreases. There is a risk.

As described above, the label prepared by applying the heat-sensitive adhesive 2 containing the substance which reacts with the alkaline solution to generate the gas on the back surface of the substrate 1 is to heat the label. The heat-sensitive adhesive 2 is activated by the above method, and the heat-sensitive adhesive 2 is applied to the surface of the bottle such as a beer bottle or a glass bottle of sake and the like for use. Then, the empty bottle is recovered and washed with an alkali cleaning liquid, and at this time, the alkali cleaning liquid is used to remove the heat-sensitive adhesive 2 on the back surface of the substrate 1.
The above substance in the heat-sensitive adhesive 2 reacts with the alkaline solution in the alkaline cleaning liquid to generate a gas such as hydrogen gas and generate bubbles. Since the heat-sensitive adhesive 2 is sandwiched between the label base material 1 and the bottle surface, bubbles generated by the gas form a gap between the label base material 1 and the bottle. It acts to widen this gap,
The label can be peeled off from the surface of the bottle by the pressure of bubbles.

As described above, the gas generated by the substance contained in the heat-sensitive adhesive 2 can be used to easily remove the label from the surface of the bottle during the alkali cleaning. It is preferable to use one having a stronger adhesive force to the label base material 1 than to the bottle. When such a heat-sensitive adhesive is used, the above substances in the heat-sensitive adhesive 2 react with the alkaline solution in the alkaline cleaning solution to generate gas, so that the gap between the label substrate 1 and the bottle is widened. When operating, the bubbles caused by the gas are pushed to the surface side of the bottle with weak adhesive force and the bottle and the heat-sensitive adhesive 2
Bubbles form a layer at the interface with and the bubbles will separate the heat-sensitive adhesive 2 from the bottle. Therefore, the label can be peeled off without leaving the heat-sensitive adhesive 2 on the surface of the bottle.

[0012]

The invention will now be illustrated by the examples. (Example) One-sided art paper ("Kinfuji one-sided art L" manufactured by Shin-Oji Paper Co., Ltd .: 85 g / m ² ) was used as a base material,
First, gravure printing and varnish coating were performed on the surface. Next, 5% by weight of an aluminum paste (containing 95% by weight of aluminum) was added to a heat-sensitive adhesive (“DLA-1” manufactured by Dainippon Ink and Chemicals, Inc.), and the mixture was sufficiently stirred and mixed to obtain the back surface of the substrate. 2 in rotary gravure printing machine
A label was prepared by applying a coating amount of 0 g / m ² .

(Comparative Example 1) 15 g / m ² of the heat-sensitive adhesive of Example (“DLA-1” manufactured by Dainippon Ink and Chemicals, Inc.) containing no aluminum paste on the back surface of the substrate.
A label was produced in the same manner as in the example, except that the coating amount was applied. (Comparative Example 2) A heat-sensitive adhesive that swells a resin in an alkaline solution (“DLA-1 manufactured by Dainippon Ink and Chemicals, Inc.”
000 ″) was used and the aluminum paste was not added, and this was coated on the back surface of the base material at a coating amount of 15 g / m ² to produce a label in the same manner as in the example.

Each of the labels prepared as described above was attached to a glass bottle of beer at a speed of 300 bottles / minute using a hot air blower type labeler for heat-sensitive adhesive manufactured by Koyo Automatic Machine Co., Ltd. When some of the labeled glass bottles were immersed in cold water at 5 ° C. and left for 1 week, the label did not peel off from the bottle, and it was confirmed that the label was practical.

Further, the glass bottle labeled as described above is allowed to stand at room temperature for 1 week, and an alkali cleaning liquid of 70 ° C. prepared with a 3% aqueous solution of sodium hydroxide is stirred with a screw at a rate of 2 times / sec. A glass bottle was washed by immersing it in this alkaline cleaning solution. Then, during the washing, the peeling state of the label from the glass bottle was observed. The results are shown in Table 1.

[0016]

[Table 1]

As can be seen from Table 1, it is confirmed that in the examples, the label is easily peeled off without the adhesive remaining on the surface of the bottle. Next, a test was conducted in which a glass bottle labeled in the same manner as above was immersed in an alkaline cleaning solution prepared in the same manner as above, the glass bottle was taken out of the alkaline cleaning solution, and the label was peeled off from the surface of the glass bottle. In the label of Example, the label could be easily peeled off without peeling between the adhesive and the glass bottle and leaving the adhesive on the surface of the glass bottle, but in the label of Comparative Example 1, the base paper was broken. I couldn't tear it off. Moreover, in the label of Comparative Example 2, the adhesive was left on the surface of the glass bottle by being peeled off between the base paper and the adhesive. From the results in Table 1 above and the results of this test, it is confirmed that the label peels off from the place where the adhesive strength is the lowest.

[0018]

As described above, according to the present invention,
Since a label was created by applying a heat-sensitive adhesive containing a substance that generates a gas when it reacts with an alkaline solution, heat-sensitive adhesive can be used when washing a bottle with a label attached with an alkaline cleaning solution. The above substance in the agent reacts with the alkaline solution in the alkaline cleaning liquid, gas such as hydrogen gas is generated to generate bubbles, and the label can be peeled by the pressure of the bubbles. At the same time, the label can be easily peeled off.

If a heat-sensitive adhesive having a stronger adhesive force to the base material than to an object such as a bottle to which a label is attached is used, the bubbles due to the gas are heat-sensitive to a bottle or the like having a weak adhesive force. The label can be peeled off without leaving the heat-sensitive adhesive on the surface of the bottle or the like because it is pushed to the interface with the heat-sensitive adhesive and bubbles can separate the heat-sensitive adhesive from the bottle or the like. .

[Brief description of drawings]

FIG. 1 is an enlarged partial cross-sectional view showing a layer structure of a label.

[Explanation of symbols]

 1 substrate 2 heat-sensitive adhesive

Claims (3)

[Claims] 1. A label comprising a back surface of a base material coated with a heat-sensitive adhesive containing a substance that reacts with an alkaline solution to generate a gas. 2. The label according to claim 1, wherein an alkali-soluble metal powder is used as a substance that reacts with an alkaline solution to generate a gas. 3. The label according to claim 1, wherein the heat-sensitive adhesive has a stronger adhesive force to the base material than to an object to which the label is attached.