JPH0118598Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a sheet with a tamper-indication function used for packaged products to prevent the contents of the package from being opened and restored by a third party. If a third party secretly opens, replaces, or adds to the contents, the fact of tampering can be easily discovered, and it is absolutely impossible to erase or repair the tampering. This invention relates to the structure of a functional sheet.

BACKGROUND ART An example of a conventional adhesive product for indicating the opening of a packaged product is one having the structure shown in FIG. This is done by providing an adhesive layer 8 with a relatively weak adhesive force on the back side of the plastic film 1, pasting the thin aluminum foil 7 closely together, and then
It has a structure with This is used by pasting it on the part 5' of the packaged product to be sealed, but when the film is removed and the package is opened, the plastic film 1 is peeled off and at the same time the adhesive layer 9 and aluminum foil 7 are removed from the packaged product. Although the aluminum foil 7 remains adhered to the surface 5', it is virtually impossible to remove it without damaging it due to its weak strength. Even if the film is reattached, it can be easily seen through the film 1, so the fact that the package was opened remains as evidence.

Another example of a conventional adhesive product for indicating the opening of a packaged product is one having the structure shown in FIG. This is done by printing characters 12 on the back side of a plastic film 1 using colorless and transparent ink that can be easily peeled off, then providing a colorless or transparent colored layer 10 on the entire surface, and then overlaying an aluminum vapor-deposited film 11. It has a structure in which an adhesive layer 9 is provided. When this is applied to the part 5' of the packaged product to be sealed and the film 1 is removed to open the package, the printed character part 12 will peel off at the same time as the plastic film 1 is peeled off, and the transparent colored layer 10 and the aluminum vapor deposited film will peel off. 11. The adhesive layer 9 is cut at the cut surface 13', the printed text portion remains on the package surface 9, and the other portions are peeled off at the adhesive layer 9. The peel-off treated characters 12 and the transparent colored layer 10 are made of materials that cannot be distinguished from each other by color, but after peeling off, the characters become embossed and can be easily identified through the film 1, so they can be easily identified through the film 1. The fact that the package was opened is left behind as evidence.

Problems that the invention aims to solve In the first example of the conventional adhesive sheet for tampering indication, thin aluminum foil is used in two stages of adhesion, and in the second example, peel-off treatment characters are printed and aluminum vapor deposition is performed. Due to these factors, both the material cost and production cost of the sheet are high, which limits its use. Additionally, the thin aluminum foil used in the first example lacks mechanical strength, and although this is necessary to improve sensitivity in detecting tampering, it is There was a drawback that reliability in indicating that the package had been opened could not be guaranteed because it could be damaged by something other than opening the package.

This invention solves the above-mentioned problems of conventional products, and creates an adhesive that requires relatively low production time and material costs, is easy to use, and can reliably perform the tamper-indicating function. The purpose is to provide sex sheets.

Measures to Solve the Problems As a result of various studies to solve the above problems, we have found that adhesive sheets that use metal powder as a filler mixed into the adhesive layer are made by attaching a part of the adhesive sheet to an adherend and then removing a portion of the adhesive sheet. They discovered that even if the peeled part is restored and reattached, the light reflection state of the unpeeled part and the peeled and restored part is clearly different and can be clearly distinguished with the naked eye. The reason for this is that the metal powder in the adhesive layer receives stress when it is peeled off, and the microscopic flow induced by this changes the orientation of the metal powder, which changes the state in which the light that passes through the film is diffusely reflected. Attempts to correct this by redissolving it with a solvent have not been successful. It has been confirmed from experience that once the orientation has changed in this way, it is absolutely impossible to restore the orientation to the state before peeling, so we believe that this idea can be used to solve the above problems. Ta. A specific structure to which the present invention is applied will be explained below.

FIG. 1 shows a cross-sectional view of a portion of an adhesive sheet according to an embodiment of the present invention.

A release agent 2 is applied to a part of the back surface of a transparent or nearly transparent colorless or colored plastic film 1. Next, a pressure-sensitive adhesive mixed with metal powder is further applied to the entire surface of the same back surface to form a pressure-sensitive adhesive layer 3, and then a release paper 4 is pasted to produce a pressure-sensitive adhesive sheet. When using this for a packaged product, it is sufficient to remove the release paper 4 and stick it directly to the part of the surface 5 of the packaged product that requires sealing, in the same way as a general pressure-sensitive adhesive sheet.

FIG. 2 is a partial cross-sectional view showing the state in which the adhesive sheet of the present invention is attached to the surface of a packaged product and then peeled off.

Since the adhesive layer 3 is sufficiently adhered to the surface 5 of the packaged product, the portion 3' to which the release agent 2 is not applied is subjected to stress for peeling off, and the surface 5 of the packaged product is peeled off or the adhesive layer is removed. Either a portion of layer 3' is left on the surface of the package and separated. However, the adhesive layer 3'' that is in contact with the area coated with release agent 2 has extremely weak adhesion with the release agent 2, so it is easily peeled off at the interface, and the adhesive layer 3'' is in contact with the area that is not coated with release agent. The adhesive layer 3' is separated and attached to the package surface 5. In this case, the adhesive layer 3 is generally extremely thin and maintains fluidity, so the stress when the two adhesive layers 3' and 3'' are separated is extremely small, and naturally the adhesive layer 3'' is almost noticeable. Since the metal powder 6' is separated without being subjected to a large amount of stress, the internal orientation of the metal powder 6' distributed therein can be maintained without changing the orientation before separation. On the other hand, since the adhesive layer 3' in contact with the part without release agent is strongly adhered to the plastic 1, the stress it receives and the effects of internal strain and flow due to it are large.
In particular, the metal powder 6'' near the cut surface 13 has an orientation that is quite different from that before peeling.This change causes a clear difference when looking at the reflected light that passes through the plastic film 1, and when the release agent 2 is applied Parts will appear embossed, as if they were printed.

As the plastic film 1 and release agent 2 used in the present invention, those commonly used in the adhesive processing field may be used in a conventional manner, but it is reflected that the plastic film 1 is relatively transparent. It is desirable for recognizing light and is not affected much by the presence or absence of coloring. As the plastic material, biaxially oriented polypropylene film (OPP) or polyethylene terephthalate film (PET) is suitable as a practical material from the viewpoint of cost and strength.

The adhesive layer 3 is an adhesive used in general adhesive products, and is not particularly limited. Various metal powders can be used as the metal powder 6 to be kneaded into this, but in particular, particles with a clear directionality such as flat, acicular, or disk shapes are preferable to particle shapes that are close to spherical. In this case, the effect of changing the direction of diffused reflection can be expected, and the effect will be clearly seen in practical use. For example, in the case of scaly aluminum powder, this effect is clearly recognized. Note that, by adding and using various dyes in the adhesive layer 3, it is not prohibited to impart gloss and color other than the metallic luster inherent to the metal powder 6.

As mentioned above, by using almost the same method as many adhesive sheets currently on the market, we devised a structure in which a part of the adhesive layer is coated with a release agent and a metal powder with clear directionality is added to the adhesive layer. , the fact that the package has been opened can be easily and inexpensively confirmed from the reflected light.

Function In the present invention, it is a practically desirable method to mix and use scaly aluminum powder in the adhesive from the viewpoint of reflection effect, cost, and handling. Furthermore, since it is advantageous for discrimination to have the part to which the release agent is applied have a relatively complex shape and be drawn in detail, it is desirable that the part be in the form of, for example, a patterned figure or a letter. For this purpose, it is convenient because it is possible to apply a common printing technique such as gravure or letterpress printing, use a release agent in the same way as printing ink, print on the back side of the plastic film, and then dry it.

Examples Examples of the present invention are shown below, but the present invention is not limited thereto.

Silicone resin diluted to 5% solids with toluene solvent (Shin-Etsu Chemical Co., Ltd.) is coated on a polyester film 38μ (Toray Industries, Inc., trade name: Lumirror) that has been subjected to corona discharge treatment to improve adhesion with silicone resin and adhesive. Co., Ltd. (trade name: KS778) was printed with the words "opened" using gravure printing (300 meshes), and this was used as the first process product. Next, 3 parts by weight of aluminum powder (Showa Aluminum Co., Ltd., trade name Altop 15-TL) was added and kneaded to 100 parts by weight of an acrylic adhesive (Seiden Chemical Co., Ltd., trade name T-207) on the printed surface. Apply adhesive to a dry thickness of 15 μm, and apply release paper (Shikoku Paper Co., Ltd.: product name).
MLAY). The product obtained in this way is made into a stamped label using a seal-cutting machine.
When it was pasted on the cellophane used for the outer packaging of confectionery boxes and removed, only the silicone-printed words "opened" remained on the cellophane.
I tried to restore it again, but the fact that it had been removed became obvious at a glance, and it was impossible to restore it.

Effects The adhesive sheet of this invention uses an extremely simple process of printing a release agent on a plastic sheet, applying an adhesive containing metal powder, and pasting the release paper together, so the work steps and operations are extremely simple. It can be implemented easily and at low cost. Therefore, if a metal powder such as scaly aluminum powder is used, the material cost is low, and the adhesive sheet can be made at a low price. Furthermore, the fact that the package has been opened is embossed on the sheet as an irrecoverable indication.
Certainty can be guaranteed, and a tamper-evident display function can be performed that leaves no room for destruction of evidence.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a portion of the adhesive sheet of the present invention having an tamper-indication function, and Figure 2 shows the adhesive sheet of the present invention of Figure 1 attached to the surface of a packaged product and then peeled off. 3 and 4 are partial sectional views showing a state in which a conventional adhesive product for tampering indication is used on the surface of a packaged product. 1... Plastic film, 2... Release agent,
3, 3', 3''...Adhesive layer, 4...Release paper, 5,
5'...Packaged product surface, 6,6',6''...Metal powder,
7...Aluminum foil, 8...Adhesive layer with weak adhesive strength,
9... Adhesive layer, 10... Transparent colored layer, 11...
Aluminum vapor deposited film, 12...Peeling treated characters, 13,1
3'...Cut surface.

Claims (1)

[Scope of utility model registration request] An adhesive sheet having an tamper-indicating function, which is formed by applying a release agent in the form of letters or marks to a base material made of colorless or colored transparent plastic film, and further applying an adhesive containing flaky metal powder to the entire surface.