JP2519415B2 - Adhesive sheet peeling detection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for detecting peeling of an adhesive sheet for confirming that the adhesive sheet has been peeled off from the surface of an adherend.

(Prior Art) Conventionally, in order to make it possible to confirm the peeling of an adhered pressure-sensitive adhesive sheet, a base material is made of a brittle material, and a pressure-sensitive adhesive is applied and formed on the back surface of the pressure-sensitive adhesive sheet, Alternatively, there is known a pressure-sensitive adhesive sheet of a type in which a release agent layer that is partially peeled off on the back surface of a base material and a metal vapor deposition material layer are sequentially provided over the entire surface, and a pressure-sensitive adhesive layer is formed by coating on the lower surface of the metal vapor deposition material layer. Has been.

These pressure-sensitive adhesive sheets are used for certification, sealing, and other purposes by being attached to products, packages, and certification mounts, and when the pressure-sensitive adhesive sheets are subsequently peeled off, the former sheet is fragile. The substrate breaks and remains on the adherend surface, and in the latter sheet, the fact that the metal vapor deposition material layer partially remains on the adherend surface together with the pressure-sensitive adhesive and the residue peels off the pressure-sensitive adhesive sheet is confirmed. be able to.

(Problems to be Solved by the Invention) In any of the above cases, the base material or metal vapor deposition material remaining on the surface of the adherend was wiped off along with the adhesive layer on the back surface thereof, and was peeled off illegally. There is a drawback that the facts cannot be found.

It is an object of the present invention to solve the problems of the conventional pressure-sensitive adhesive sheet, and to provide a method capable of detecting the fact that the pressure-sensitive adhesive sheet is peeled off even if the residue on the adherend surface is wiped off. .

(Means for Solving Problems) In the present invention, in the pressure-sensitive adhesive layer formed by coating on the surface of the base material of the pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive sheet is adhered to the surface of the adherend, the pressure-sensitive adhesive sheet moves to the surface of the adherend. The above-mentioned object was achieved by mixing a fluorescent dye that leaves a fluorescent dyeing trace therein and confirming the peeling of the pressure-sensitive adhesive sheet from the fluorescent dyeing trace.

(Example) Next, the Example of this invention is described.

Any material can be used for the base material of the pressure-sensitive adhesive sheet used in the present invention, and it can be used from fragile to strong materials such as paper, synthetic polymer film, metal foil, metal, and synthetic plate, and its opacity. , Transparent does not matter. It is conventional that the desired printed display can be made on the front surface or the back surface of the substrate. A pressure-sensitive adhesive layer is formed on one surface of the substrate directly or indirectly through a partial release agent layer and an entire metal vapor deposition material layer as in the conventional example. As the rubber, any conventionally known rubber type, acrylic type, or the like can be used. According to the present invention, when a pressure-sensitive adhesive sheet is attached to the surface of an adherend in this pressure-sensitive adhesive layer, a fluorescent dye that migrates to the surface of the adherend and leaves a fluorescent dyeing trace thereon is mixed, and the pressure-sensitive adhesive sheet is peeled off. Is confirmed by the trace of the fluorescent dyeing.

The fluorescent paint is a material that absorbs ultraviolet rays and emits light (fluorescence), and as the fluorescent dye, a coumarin-based fluorescent dye,
A quinazolone derivative fluorescent dye, a perylene derivative dye, and the like are used, and can be appropriately selected and used from the above dyes depending on the solvent used for preparing the pressure-sensitive adhesive and the type of adherend. It is also possible to use it in combination with other dyes. The amount of the dye added is generally 0.01 to 1 as solid content per 100 parts by weight of the adhesive.
It is sufficient to add 0 part by weight. If it exceeds 10 parts by weight, the adhesive strength of the adhesive may be reduced. It is preferably 0.05 to 5 parts by weight.

After sticking a pressure-sensitive adhesive sheet prepared by mixing the above-mentioned ratio of the fluorescent dye in the pressure-sensitive adhesive layer on the surface of the adherend, even if it is completely peeled off after a lapse of time, the pressure-sensitive adhesive will remain on the surface of the adherend. The fluorescent dye mixed in the agent layer migrates to leave a trace of fluorescent dye having the same shape as that of the adhesive sheet, and the fact of this peeling can be clearly detected by irradiation with ultraviolet rays such as black light. Therefore, particularly as in the conventional example, the base material is limited to a brittle base material,
It is not necessary to interpose a vapor deposition material layer, and peeling can be detected with only two layers of an arbitrary base material and an adhesive layer. Of course, the present invention can be carried out with the pressure-sensitive adhesive sheet having the structure of the conventional example, and even if the residual portion on the surface of the adherend is wiped off, a dyeing trace remains and the conventional problem is solved.

The shape of the fluorescent dye adheres to the shape of the adhesive sheet, so it is possible to know the shape of the adhesive sheet attached to it, and in addition to detecting unauthorized peeling, positioning in the processing process It can be used as a mark.

Adhesive sheets include so-called sheets as well as plates. Shapes and dimensions are arbitrary, and labels, tapes, etc. with the product or product proof printed on the surface are used according to the application. it can. If the present invention is applied to, for example, a vehicle body plate on which a vehicle body number of an automobile is described, when the vehicle body plate is illegally peeled off from the vehicle body, a trace of fluorescent dyeing remains on the trace and the illegality can be detected.

Example 1 100 parts by weight of an acrylic adhesive was mixed with Solvent Yellow 1
0.5 parts by weight of No. 6 and 2.5 bis (5.
2.5 parts by weight of tertiary butyl benzoxazolyl (2)) thiophene was added, and this was applied to the base material surface of a polyethylene terephthalate film having a thickness of 50 μm to a thickness of 25 μm to form a pressure-sensitive adhesive sheet, and then the melamine coating was applied. When it was attached to a plate (white), left at room temperature for 24 hours, and peeled off, the attachment trace turned yellow. When the portion was irradiated with ultraviolet rays, it emitted fluorescence.

Example 2 100 parts by weight of a transparent acrylic adhesive was mixed with 2 parts of a fluorescent dye.
Add 0.32 parts by weight of 5 bis (5-tert-butylbenzoxazolyl (2)) thiophene and add 25 μm to the base material surface of a polyethylene terephthalate film with a thickness of 50 μm.
The pressure-sensitive adhesive sheet coated with a thickness of m to form a pressure-sensitive adhesive layer was attached to an adherend of a urethane rubber molding plate and a polypropylene molding plate, respectively, and left in a constant temperature bath at 50 ° C and peeled off after 3 days. The migration of the fluorescent dye mixed in the adhesive layer was clearly observed on each adherend surface. At the same time, the pressure-sensitive adhesive sheet of Example 1 was adhered to the adherends of the urethane rubber molded plate and the polypropylene molded plate and left in a constant temperature bath at 50 ° C. and peeled off after 3 days. The migration of the fluorescent dye mixed in the adhesive layer was clearly observed. The transferability of the fluorescent dye was confirmed by irradiating it with ultraviolet rays using a black light and observing whether or not the adherend surface emits fluorescence.

Example 3 Each of the pressure-sensitive adhesive sheets prepared in Examples 1 and 2 was adhered to a melamine coated plate, a urethane rubber molded plate, and a polypropylene molded plate, respectively, and allowed to stand at room temperature for 5 days and then peeled off, and the adherend surface of each adherend was adhered. The treatment for removing the fluorescent dyeing trace of No. 1 by various solvents shown in Table 1 below was performed. The removal treatment is carried out by (a) wiping the dyeing trace with each gauze soaked with each solvent, and (b) immersing each adherend in each solvent tank for 24 hours.
The surface of the adherend after the removal treatment was visually inspected and whether or not fluorescence was emitted by black light was visually inspected. The results are shown in Table 1.
It was as shown in. In the table, ◯ indicates that the transferred fluorescent dye did not fall off, and Δ indicates that the transferred fluorescent dye fell off a little but still remained.

As is clear from Table 1 above, the transferred fluorescent dye is difficult to be removed easily and has excellent solvent resistance. Therefore, after peeling the pressure-sensitive adhesive sheet, the base material piece and the metal deposition material remaining on the adherend are removed. Even if it is wiped off, the transferred fluorescent dye cannot be wiped off, which is effective in ensuring that the illegal peeling is surely detected.

Example 4 To 100 parts by weight of a transparent acrylic adhesive, 0.32 parts by weight of a coumarin-based fluorescent dye, a quinazolone derivative fluorescent dye, or a pererin derivative fluorescent dye was added to prepare three types of adhesives, each having a thickness of 50 μm. Adhesive sheet is formed by forming a 25 μm thick adhesive layer on the white fragile vinyl chloride base material, and these adhesive sheets are attached to an adherend of a white melamine coated plate and placed in a 50 ° C. constant temperature bath. After leaving it for a day, it was peeled off and the dyeing trace on the surface of the adherend was examined. As a result, migration dyeing of all fluorescent dyes was observed.

(Effect of the invention) As described above, according to the present invention, in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive sheet is adhered to the adherend surface, it is transferred to the adherend surface and a fluorescent dyeing trace is formed on it. Since the fluorescent dye to be left was mixed in and the peeling of the adhesive sheet was confirmed by the fluorescent dyeing trace, the fact that the adhesive sheet was peeled off even after wiping off the residue on the surface of the adherend still shows the fluorescent dyeing trace. With this, it is possible to reliably detect by irradiation of ultraviolet rays, the material of the base material and the adhesive can be freely selected, so the manufacturing is easy, and since the fluorescent dye is used, there is little stain even if it touches the adhesive layer .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Sato 23-23 Honmachi, Itabashi-ku, Tokyo FSK Co., Ltd. (56) Reference JP-A-55-21468 (JP, A)

Claims (1)

(57) [Claims] 1. A fluorescent material, which is applied to a base material surface of a pressure-sensitive adhesive sheet, moves to the surface of the adherend when the pressure-sensitive adhesive sheet is adhered to the surface of the adherend, and leaves a fluorescent dyeing mark on the surface. A method for detecting peeling of an adhesive sheet, which comprises mixing a dye and confirming the peeling of the adhesive sheet by the trace of the fluorescent dyeing.