JPH0968926A - Forgery preventive method and its label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forgery preventive method capable of easily forming concealed marks as well, easily deciding the authenticity of an object to be inspected, improving the property to prevent the forgery, facilitating labeling, improving production efficiency and handling quality and allowing the work to efficiently mount a label having excellent durability to an adherend. SOLUTION: This forgery preventive method comprises using a phase difference film 1 as the object to be examined and deciding the occurrence of a color change by whether the visible characteristic of this object to be inspected is visible or not via a polarizing plate 2 as the criterion for the authenticity. As a result, the excellent property to prevent the forgery capable of easily deciding the authenticity by a change in the visibility characteristic via the polarizing plate is obtd. and the easy labeling of the object to be examined is possible. In addition, the efficient formation of the concealed marks by the simple treatment of forming the region where the phase difference varies is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forgery prevention method and a label thereof, which utilizes a change in visual recognition characteristics of a retardation film through a polarizing plate.

[0002]

BACKGROUND ART Conventionally, as a method for preventing forgery, there is known a method for preventing forgery by photochromic printing in which a special ink containing a phosphor that responds to ultraviolet rays is printed so that it can be seen only when it is irradiated with ultraviolet rays. (Japanese Patent Laid-Open No. 54-13799). However, it is difficult to form a transparent and durable special ink that can be used for the formation of hidden marks, and it is difficult to form something that has a high level of durability that can be used for automobile parts, etc. The irradiation device also has a problem of poor portability.

On the other hand, in a safety label obtained by laminating a print sheet which is easily damaged on a supporting sheet with a window, when the print sheet is peeled off from an adherend, the print sheet is damaged and the label is reused. A method of preventing forgery that made the above-mentioned impossible is also known (Japanese Patent Publication No. 61-47426). However, it takes a lot of time and labor to form a safety label, and it is easily damaged, so it is easily damaged even during proper use and its handleability is poor, and the work efficiency of adhering to an adherend is also poor. there were.

[0004]

DISCLOSURE OF THE INVENTION The present invention is capable of easily forming a hidden mark and is excellent in durability, is capable of easily judging whether a test object is true or false, and is excellent in forgery prevention property, and is easy to label and manufacture. The purpose is to develop a forgery prevention method that is highly efficient and easy to handle and can be efficiently attached to an adherend.

[0005]

Means for Solving the Problems The present invention uses a retardation film as an object to be inspected, and a true or false judgment criterion is that a color change occurs depending on whether or not the inspecting property of the object is visually recognized through a polarizing plate. The present invention provides a forgery prevention method characterized by the following.

[0006]

EFFECTS OF THE INVENTION According to the above-mentioned constitution, it is possible to easily judge the authenticity by the change of the visual characteristic through the polarizing plate, and it is excellent in the forgery prevention property, and the object can be easily labeled. Hidden marks can be efficiently formed by a simple process of forming the phase difference area, and it is possible to obtain a forgery prevention label that has excellent durability, manufacturing efficiency and handleability, and can be efficiently attached to an adherend. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The anti-counterfeiting method of the present invention uses a retardation film as an inspection object to determine whether or not the visual characteristics of the inspection object cause a color change depending on whether or not it is visually recognized through a polarizing plate. Is used as the criterion.

The anti-counterfeiting method of the present invention can be preferably carried out by forming a label for a test object with a retardation film and using the label. An example of the label is shown in Figure 1.
(A) and (b). 1 is a label and 2 is a polarizing plate. Reference numeral 11 is a hidden mark formed in a region where the retardation in the retardation film forming the label is partially different.

In the above label, when there is no polarizing plate, the appearance is the same as that of the retardation film. Therefore, when the retardation film is made of a colorless transparent material, the background can be seen through (FIG. 1a). On the other hand, when viewed through the polarizing plate, it can be seen in a colored state based on the phase difference (FIG. 1b). Further, when the retardation film has a retardation difference area, a difference appears in the coloring (coloring) based on the retardation difference through the polarizing plate, and the difference portion can be visualized by the color change. , Hidden mark 1
1 can be manifested.

In the present invention, the retardation film is
A material formed of an appropriate birefringent material such as plastic or liquid crystal polymer may be used. In the case of forming a retardation difference region as a hidden mark, a stretched film can be preferably used in terms of its formation efficiency and the like. In the stretched film, the retardation region can be directly formed easily by a simple operation such as a writing method.

That is, the stretched film can have a difference in retardation by partially varying the degree of molecular orientation, and the partial difference in the degree of molecular orientation can be easily caused by heat or / and a penetrating agent. It can be applied, and a complicated hidden mark can be formed easily and efficiently.

The method of partially differentiating the degree of molecular orientation by the heat or / and the penetrating agent is, for example, a method of partially applying heat above the glass transition temperature (heat distortion temperature) to the stretched film. Can be achieved. In this case, the heat causes the degree of molecular orientation in the stretched film to partially decrease, which causes a partial difference in retardation.

On the other hand, the molecular orientation degree of the stretched film can be partially different even in the system in which the penetrating agent, for example, a chemical solution such as an organic solvent capable of dissolving or swelling the stretched film is partially applied. . In this case, the degree of molecular orientation of the stretched film is partially reduced due to the permeation of the drug, and thus the retardation is partially different. According to the method using heat or / and the penetrating agent, it is easy to obtain a label in the state of a continuous film of a single layer without the need for lamination treatment or continuous treatment.

The stretched film can be obtained, for example, by subjecting a polymer film to stretching treatment by an appropriate method such as uniaxial or biaxial. From the viewpoint of controlling the retardation, a stretched film excellent in uniformity of retardation can be preferably used because the molecules are oriented as uniformly as possible. Therefore, any conventional retardation film can be used. As the polymer film forming the stretched film, an appropriate film made of transparent plastic can be used and is not particularly limited.

Incidentally, examples of the polymer film include polycarbonate-based polymers, polyester-based polymers such as polyarylate and polyethylene terephthalate,
Polyimide-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, polystyrene-based polymer, polyolefin-based polymer such as polyethylene and polypropylene, polyvinyl alcohol-based polymer, cellulose acetate-based polymer, polyvinyl chloride-based polymer , A film made of a thermoplastic polymer such as polymethylmethacrylate polymer. Further, a film made of a liquid crystal polymer can also be used.

In the above-mentioned operation of lowering the molecular orientation degree of the stretched film by heat or / and a penetrating agent, the method of applying heat or the method of applying the penetrating agent is not particularly limited, and for example, heating via a heat source is used. It is possible to adopt an appropriate method such as a method or a method of applying heat via electric discharge, or a method of applying a penetrating agent to a stretched film such as an organic solvent. Both methods of applying heat and applying the agent can be used. It can also be used together.

The hidden mark formed as a region having a different phase difference is not particularly limited and can be appropriately determined according to the purpose of use. By the way, it is possible to form an appropriate hidden mark composed of a sentence, a design, an identification mark, a striped pattern, a grid pattern, a checkered pattern, and other patterns by using characters, figures, symbols, and the like. As the forming means, an appropriate means such as a handwriting method, a printer method, or a printing machine method can be adopted.

In the method of treating the above-mentioned stretched film with heat and / or a penetrating agent, an appropriate heating type or chemical jet of a thermal transfer printer or an ink jet printer is used in view of efficient formation of a fine pattern. A method of applying heat or applying a medicine with a printer of a type is preferable. Further, a desired hidden mark such as a fine pattern can be efficiently formed by a heating method using a laser beam, a press heating method such as a stamp method, or a method in which a drug is applied by a mask method or a printing method. . By the way, through the above-mentioned various printers, 1/1000 to 1/10
It is easy to form a fine area of about 0 mm ² .

In the above case, the region of the stretched film in which the degree of molecular orientation is lowered to change the retardation may be a region of the target hidden mark position, or a region other than the target hidden mark position, That is, the region of the target hidden mark position may remain with the degree of molecular orientation in the original stretched film, and the region other than that position may be the region with the reduced degree of molecular orientation. The latter operation of lowering the degree of molecular orientation is
For example, it can be performed by a method of masking a target position region with a resist or the like and treating with heat or a chemical.

There is no particular limitation on the phase difference to be given to the area where the hidden mark is formed. From the viewpoint of visualizing hidden marks by coloring through a polarizing plate, 300-
It is preferable to have a phase difference in the range of 700 nm. In the present invention, by making the difference in retardation to be two or more steps, it is possible to form a hidden mark of two or more colors due to the difference in color development. From the viewpoint of preventing forgery, a state in which the color is complicated and has a large number of different colors is preferable, but it is generally a hidden mark composed of 20 colors or less, preferably 10 colors or less, and particularly 2 to 7 colors. In that case, it is possible to set an arbitrary retardation state within a range from the state where no retardation is shown (degree of molecular orientation 0) to the retardation state of the original retardation film.

In the case of forming a region having a phase difference difference by the method of reducing the degree of molecular orientation described above, the phase difference can be controlled by the degree of decreasing the degree of molecular orientation. To control the degree of decrease in the molecular orientation, control the amount of heat by adjusting the heating temperature and heating time, adjust the permeability such as solubility and swelling depending on the type of drug, and control the penetration degree by adjusting the processing time. It can be performed by an appropriate method such as a method.

In the present invention, the thickness of the retardation film is
It can be appropriately determined according to the purpose of use and the desired retardation value (product of difference in refractive index of birefringence and thickness). Generally, it is 2 mm or less, especially 500 μm or less, especially 5 to 300 μm based on a monolayer film such as a stretched film.
The thickness of

The retardation film for forming the anti-counterfeit label has the purpose of facilitating visualization of hidden marks when a polarizing plate is interposed and coloring the label when a polarizing plate is not interposed. If necessary, an appropriate additional layer such as a reflective layer, a transparent cover layer for preventing contamination, or an adhesive layer for adhering and fixing to an adherend can be provided.

If necessary, the retardation film, the reflective layer, etc. may be provided with an information display layer having a pattern or the like according to the above-mentioned hidden mark which can be visually recognized without a polarizing plate. The information display layer may be formed by an appropriate method such as a printing method, and its information content is arbitrary.

FIG. 2 shows an example in which the reflective layer 3, the adhesive layer 4 and the transparent cover layer 5 are provided. As is clear from the illustrated example, the reflective layer 3 is provided on the back surface of the label, that is, on the side opposite to the viewing side. The reflective layer can be formed by an appropriate method and is not particularly limited. A preferable reflective layer has a metal reflective surface having excellent surface reflectance, such as aluminum, gold, silver, tin, or an alloy containing such a metal.

The reflective layer having a metal reflective surface is formed, for example, by attaching a vapor deposition film to a film or the like by a thin film forming technique such as a vacuum vapor deposition method, a sputtering method, an ion plating method or a polymer liquid containing a metal powder. Appropriate method such as coating and printing on a film or the like, a method of adhering a metal foil or the like to a retardation film, or a method of using a retardation film as the film or the like and directly attaching a vapor deposition film or a printing layer to the retardation film Can be done at.

An adhesive layer for the purpose of adhering to an adherend,
It is provided on the back surface side of the label via a reflective layer if necessary. The adhesive layer may be formed of an appropriate adhesive substance, but an adhesive layer is preferable from the viewpoint of easy adhesion to an adherend and the like. For its formation, for example, an appropriate adhesive substance such as a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive or a polyvinyl ether-based adhesive can be used. From the viewpoint of preventing changes in retardation characteristics, those that do not require a high-temperature process or long-time treatment at the time of curing or drying are preferable.

The adhesive layer is preferably covered with a release sheet 6 for the purpose of preventing contamination or the like until it is put into practical use as illustrated in FIG. In that case, a long sheet may be used for the release sheet to form a plurality of label units in a form of a continuous body temporarily attached via an adhesive layer. As the release sheet, an appropriate one such as a resin-coated paper or a resin film whose surface is coated with a release agent such as a silicone-based release agent which is well known for a usual label can be used.

The transparent cover layer provided on the surface of the label for the purpose of protecting the surface of the label can be formed by an appropriate method such as a transparent film or a resin coat. An additional layer such as a reflective layer, an adhesive layer, or a transparent cover layer can be provided at an appropriate stage before or after forming a hidden mark by providing a region having a phase difference.

The label can be given a weakening function by subjecting the label to easy-damage processing such as perforations and cuts. According to this, when it is peeled off from the adherend, it is more likely to be damaged, and if it is damaged, reuse becomes difficult.

The anti-counterfeiting method of the present invention is to visually recognize, through a polarizing plate, a label made of a retardation film in which a hidden mark made of a retardation difference region is provided if necessary. That is, the difference in the phase difference cannot be perceived with the naked eye, and therefore the color development and the hidden mark cannot be known even by looking at the label, but the color is visually recognized through the polarizing plate, and the difference in the phase difference is also present. The parts appear in different coloring states and the hidden mark can be visualized and perceived. Therefore, the authenticity can be determined with good reproducibility by the presence or absence of the polarizing plate.

As the polarizing plate, an appropriate one can be used without any particular limitation. Generally, a film made of a hydrophilic polymer such as polyvinyl alcohol is treated with a dichroic dye such as iodine and stretched, or a plastic film such as polyvinyl chloride is oriented with polyene. And a polarizing film covered with a sealing film for protection.

The forgery prevention method of the present invention can be used for various purposes such as the purpose of certifying authentic products. In that case, in the present invention, a polarizing plate is previously attached to the label,
It is possible to use it in a state where the coloring state or hidden mark is already displayed, or use the label without the polarizing plate and confirm the coloring state of the label or the hidden mark through the polarizing plate if necessary It can also be used as a method for determining.

[0034]

【Example】

Example 1 A polycarbonate film having a thickness of 60 μm was stretched 1.7 times at 155 ° C. to give a film having a thickness of 20 μm on both sides.
Thickness of 38μm with acrylic adhesive layer of m or 50μm
Al-deposited polyester film on which the Al-deposited side is adhered, and the surface where the acrylic adhesive layer remains is treated with a silicone-based release agent.
Was adhered to obtain an anti-counterfeit label. The appearance of this label was Al color, but the Al color was discolored when viewed through a polarizing plate.

Example 2 A polycarbonate film having a thickness of 60 μm was stretched 1.7 times at 155 ° C. and heated and printed at equal intervals through a 0.4 mj / dot thermal transfer printer.
An anti-counterfeit label was obtained in the same manner as in Example 1 except that after the hidden letters b and c were given, letters A, B and C were further printed through the ink ribbon cartridge. The appearance of this label was such that only the letters A, B, and C applied to the background color of Al through the ink ribbon cartridge were recognized, but when viewed through the polarizing plate, the Al color changed color. The hidden letters a, b, c could also be perceived.

Example 3 An anti-counterfeit label was obtained in the same manner as in Example 2 except that toluene was handwritten with a brush instead of the paint instead of the thermal transfer method. The appearance of this label was Al color, but when viewed through a polarizing plate, the Al color changed color, and a,
I was able to perceive the hidden letters b and c.

Example 4 A label obtained according to Example 2 was cut, and then,
A polyester film having a thickness of 15 μm was adhered to the surface to provide a protective cover, the release sheet on the back surface was peeled off, and the sheet was adhesively fixed to a glass plate. Then, after the lapse of one hour, the label was peeled off from the glass plate, and the main body of the label broke from the cut portion and became unusable.

[Brief description of drawings]

FIG. 1A is an explanatory plan view of a visually recognized state when a polarizing plate is not provided. FIG. 1B is an explanatory plan view of a visually recognized state when a polarizing plate is provided.

FIG. 2 is a cross-sectional view of an example label

[Explanation of symbols]

1: Label (11: Hidden mark composed of regions with different retardation) 2: Polarizing plate 3: Reflective layer 4: Adhesive layer 5: Transparent cover layer 6: Release sheet

Claims (13)

[Claims] 1. A true / false judgment criterion is that a retardation film is used as an object to be inspected, and a color change occurs depending on whether the inspecting property of the object to be inspected is visually recognized through a polarizing plate. Anti-counterfeiting method. 2. The retardation film according to claim 1, wherein the retardation film partially has a region having a different retardation, and when the region is visually recognized through a polarizing plate, it can be visualized as a changed portion of color development. An anti-counterfeiting method. 3. The method for preventing forgery according to claim 2, wherein the retardation film is a stretched film, and the stretched film has a retardation difference region due to a partial difference in the degree of molecular orientation of the stretched film. 4. The forgery prevention method according to claim 3, wherein the partial difference in the degree of molecular orientation in the stretched film is imparted by heat or a penetrating agent. 5. The forgery prevention method according to claim 1, wherein the retardation film has an information display layer. 6. The method for preventing forgery according to claim 1, wherein the retardation film has a reflective layer on its back surface. 7. The forgery prevention method according to claim 6, wherein the reflective layer has a metal reflective surface. 8. The forgery prevention method according to claim 6, wherein the reflective layer has an information display layer. 9. The method for preventing forgery according to claim 1, wherein the retardation film has an adhesive layer for adhering an adherend on its back surface. 10. The method for preventing forgery according to claim 1, wherein the retardation film has a transparent cover layer on its surface. 11. An anti-counterfeit label comprising the retardation film according to claim 1. 12. The anti-counterfeit label according to claim 11, wherein the anti-counterfeit label is subjected to easy-damage treatment. 13. The anti-counterfeit label according to claim 11, which is temporarily attached onto a release sheet via an adhesive layer.