JP2001246829A - Forgery preventing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a forgery preventing sheet having no fluorescent printing ink present on its surface at all, incapable of confirming a mark of fluorescent printing under ordinary solar rays, fluorescence or white light at all, capable of well performing later printing and also excellent in forgery preventing effect. SOLUTION: The forgery preventing sheet comprises a multilayered structure of at least three or more layers and the opacity of both outer layers (a front paper layer and a rear paper layer) is 20-92% and a printing layer using fluorescent pigment is provided on the inner surface of at least either one of both outer layers. The opacity of both outer layers is preferably 40-92%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forgery prevention sheet having an excellent forgery prevention effect. The anti-counterfeit sheet according to the present invention is applied as paper used for banknotes (banknotes), bills, checks, stock certificates, bonds, gift certificates, betting / car tickets, various cash vouchers, various cards, passports, and the like. It is suitable for printing as a tag label by printing a logo, character, or the like that recognizes the brand on clothing or jewelry with a specific visible pattern that cannot be easily imitated or forged.

[0002]

2. Description of the Related Art Since a cash voucher or the like as exemplified above has a certain monetary and economic value, it is necessary to take measures for distinguishing a genuine product from a counterfeit product to prevent forgery or tampering. Need to be prevented.

[0003] As forgery prevention paper, there is known a paper provided with a pattern print on the surface using an ink containing a dye or pigment that emits a fluorescent color when irradiated with ultraviolet light using a lamp such as a black light. However, if dyes and pigments that fluoresce in the same hue are obtained, they have the disadvantage that they can be easily forged using known printing means, and the effect of preventing forgery has been insufficient. In addition, since the fluorescent printing surface is exposed on the surface, the physical properties of the sheet surface differ between the fluorescent printing part and the non-printing part, and ultraviolet light is irradiated by changing the angle of the resin component etc. of the fluorescent ink used. There is also a problem that the image can be visually observed without any problem, and when a normal pattern printing or a laser printer or a thermal transfer printer is performed in a later step, a printing failure or uneven gloss of a printed portion occurs.

[0004] In Japanese Patent Application Laid-Open No. 9-52431, as described above, printing is performed with water-soluble ink in the wet state during papermaking of paper as a sheet material, and the ink is present on the surface in a form impregnated inside the paper. Trying to solve a problem. However, this method also cannot solve the problem that uneven absorption of ink tends to occur when printing a pattern using a normal printing ink, because a large amount of fluorescent ink is distributed near the surface of the paper.

In Japanese Patent Application Laid-Open No. 3-230996, an opaque layer is provided on the upper surface of paper containing a fluorescent agent on the entire surface, and a pattern is printed on the opaque layer with transparent ink, so that only the transparent ink print portion emits fluorescent light. Although a method in which a fluorescent dye is internally added at the time of paper making has a poor light resistance, the light emitting property is lost after long-term use. In this method, it is necessary to print the fluorescent pigment on the entire surface of the paper in advance. However, since the fluorescent pigment is generally expensive, the cost is higher than printing only a pattern to be fluorescently colored.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an anti-counterfeit sheet capable of solving all of the problems in the conventional anti-counterfeiting technology described above.

More specifically, an object of the present invention is to provide an anti-counterfeit sheet in which no fluorescent printing ink is present on the surface of a paper, and therefore, when printing is performed in a later step by ordinary printing, laser printer, thermal transfer printer, etc. In addition, there is no problem in appearance, such as trouble in the process, transfer of printing / printing surface, or uneven absorption due to uneven absorption.

Another object of the present invention is to provide a fluorescent pigment coloring type anti-counterfeit paper which cannot be easily forged even if a similar fluorescent agent or ink is obtained by providing a fluorescent pattern inside the sheet. .

Another object of the present invention is to provide a low-cost forgery prevention sheet in which expensive fluorescent ink is used only for a required pattern printing portion.

[0010]

In order to achieve the above object, the forgery prevention sheet according to the present invention has a multilayer structure of at least three or more layers, and the opacity of both outer layers is 20 or less.
And a print layer using a fluorescent pigment is provided inside at least one of the outer layers. The opacity of both outer layers is more preferably in the range of 40-92%.

[0011] A forgery prevention sheet according to another aspect of the present invention is provided with a paper layer having an opacity in the range of 20 to 92% on both sides of a substrate, and a fluorescent pigment on the back side of at least one of the paper layers. It is characterized in that the used printing layer is provided.

[0012] A forgery prevention sheet according to still another aspect of the present invention is provided with a printing layer using a fluorescent pigment on at least one surface of a substrate, and further having an opacity of 20 on both sides thereof.
It is characterized in that a coating layer in the range of -92% is provided.

[0013] A forgery prevention sheet according to still another aspect of the present invention is provided with a printing layer using a fluorescent pigment on at least one surface of a substrate, and further having an opacity of 20 on both sides thereof.
It is characterized in that a paper layer in the range of -92% is provided.

As the substrate in the forgery prevention sheet, any one of paper, film, woven fabric and nonwoven fabric or a laminate thereof can be used. In addition to paper, any material such as woven fabric, film, or nonwoven fabric can be used as the base material of the anti-counterfeit sheet. It is possible to adopt a configuration in which a difference from a normal paper sheet material can be easily determined by the difference.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Example 1> Wood pulp (NBK)
P10%, LBKP90%) and calcium carbonate 15% by weight based on pulp weight, and the basis weight is 8 g / m 2, 20 g / m 2, 30 g / m 2, 5 g
Fine papers of 0 g / m 2 and 130 g / m 2 were prepared by a conventional method, and the surface was coated with a sizing agent and starch and calendered to obtain samples. The opacity of each of the obtained paper samples was measured in accordance with JIS-P8138 "Opacity of paper". The measured values obtained are as follows.

On the back side of the obtained paper, a fluorescent pigment aqueous dispersion (trade name: LUMIUX YEL) which emits yellow-green fluorescence is provided.
Gravure printing was carried out using an ink obtained by mixing LOW CD 997 (manufactured by Riedel-Hahn) with an acrylic emulsion to provide a fluorescent ink print layer having a star pattern.

The resulting five types of fluorescent printing paper are used as front paper, and the same weight basis paper without fluorescent printing is used as back paper, and a biaxially stretched transparent PET film having a thickness of 50 μm is laminated in the middle. By laminating by a conventional method using a dry adhesive, a laminated paper having a laminated structure of front paper (having a fluorescent ink print layer on the back surface) / PET / back paper was prepared. The structure of the laminated paper is schematically shown in FIG.

The five types of laminated paper thus obtained were irradiated with ultraviolet light from the front side and the back side using a 4 W black light, observed from the front side, and the star pattern printed with the fluorescent ink turned yellow-green. The visual appearance was visually judged, and those in which the fluorescent colored star pattern could be clearly confirmed were evaluated as ○, those in which it could be slightly confirmed as Δ, and those in which they could not be seen at all were evaluated as ×.
In addition, it is also visually determined whether or not the trace of star pattern printing of fluorescent printing can be confirmed under normal sunlight without turning on the black light, × those that can be confirmed, Δ that can be slightly confirmed, and no print trace at all Those that could not be done were marked with ○. The results of these visual determinations are as shown in the table of FIG.

As shown in the table of FIG. 2, when the basis weight of the paper on the front and back is 8 g / m 2, both the irradiation from the front side and the irradiation from the back side are performed according to the black light irradiation. Although the star pattern printed with the fluorescent ink could be clearly observed, the print trace of the star pattern could be easily observed even under sunlight.
On the other hand, when the basis weight of the front and back paper was 130 g / m 2, no printing trace of the star pattern could be observed at all under the sunlight, but the fluorescent coloring pattern could be observed even when irradiated with black light. And it was impossible to judge the authenticity.

From these results, in order to observe the star pattern printed with the fluorescent ink at the time of irradiating ultraviolet rays from both the front and back surfaces, and not to observe the print trace under the sunlight, at least the front and back layers (paper) are required. It has been determined that it is necessary to have an opacity in the range of 20-92% each. In addition, when the basis weight of the front and back paper was 20 g / m 2, a slight trace of printing was observed under the sunlight, so that a star pattern printed with the fluorescent ink at the time of irradiation with ultraviolet light was observed, and under the sunlight. In order for no print marks to be observed, it is necessary that at least the front and back layers (paper) each have an opacity in the range of 40 to 92%.

<Embodiment 2> On the printing surface of the fluorescent-printed paper of 50 g / sq.m.
A floral pattern was printed using a transparent ink having the following composition. Clarite DC (Daiwa Chemical Industry Co., Ltd.) 80 parts Toluene 20 parts

The paper provided with the fluorescent ink print layer on the back side as described above and further provided with the transparent ink print layer thereon is used as the front paper, and both the fluorescent ink print layer and the transparent ink print layer are provided. Weight (50g /
As in Example 1, a biaxially-stretched transparent PET film having a thickness of 50 μm is laminated and sandwiched in the middle of the paper as in Example 1, and then laminated by dry lamination using an ordinary adhesive. , Surface paper (has a fluorescent ink print layer and a transparent ink print layer on the back side)
A laminated paper having a laminated structure of / PET / paper was prepared. FIG. 3 schematically shows the structure of the laminated paper.

In the same manner as in Example 1, this laminated paper was irradiated with ultraviolet light from both the front and back sides using a 4 W black light, and under normal sunlight without turning on the black light. It was visually determined whether or not the pattern could be confirmed. As a result, almost the same results as in the table of FIG. 2 were obtained. Further, when the paper was seen through, a watermark pattern of a flower pattern printed with the transparent ink was observed from both the front side and the back side.

<Comparative Example 1> The front paper and the back paper used in Example 1 were prepared in the same manner as in the Example except that the non-printed surface and the PET film were bonded together with the fluorescent ink printing layer of the front paper facing the front side. Paper (with a fluorescent ink printing layer on the front side) /
A laminated paper having a PET / paper laminated structure was obtained. That is, the laminated paper has a structure schematically shown in FIG.

When a pattern was printed on the laminated paper with paper ink using a sheet-fed offset printing press, the difference in the ink absorbency between the fluorescent-printed star-pattern printed portion and the non-printed portion caused uneven glossiness of the star-pattern pattern. Occurred. In the case of black light irradiation from the front side, a yellow-green star pattern was clearly observed, but it could hardly be seen by irradiation from the back side, and it could only be slightly confirmed when irradiated in the dark room. . When the star print surface was observed under sunlight, a star print pattern was clearly visible.

Example 3 A star pattern was similarly gravure-printed on the surface of a woven fabric made of 70 denier nylon yarn using the fluorescent pigment ink used in Example 1. A paint having the following formulation was applied to both sides of the obtained printed nylon woven fabric so that the opacity of the coating layer after the calendering treatment was 70%. After the coating, the coating layer was immersed in water for 5 minutes, washed with water, After drying, a microporous membrane layer (coating layer) of 70 g / m 2 of nylon resin was provided, and calender treatment was performed to obtain a white sheet having a smooth surface. The obtained white sheet has a laminated structure of a surface coating layer / a nylon woven fabric (having a fluorescent ink printing layer on the front surface side) / back coating layer, as schematically shown in FIG. 6-nylon 20 parts by weight Methanol 58 parts by weight Calcium chloride 24 parts by weight Calcium carbonate 7 parts by weight

When the color development luminance of the fluorescent print pattern (star pattern) was visually judged on the white sheet under the same conditions as in Example 1, the yellow-green emission of the star pattern was clearly visible when irradiated with ultraviolet light, and the sunlight was Since no print trace could be confirmed below, it could be confirmed that this could be a preferred embodiment of the present invention. The white sheet also had good suitability for various printings such as lithographic offset printing and suitability for a thermal transfer printer.

<Embodiment 4> The thickness of 50 μm used in Embodiment 1
gravure printing of a star pattern on the surface of the biaxially stretched transparent PET film with the fluorescent pigment ink used in Example 1 in the same manner as described above, and the unprinted basis weight used as the back paper in Example 1 was 50 g / m 2. 6 by dry lamination bonding using a conventional adhesive on both sides thereof, as schematically shown in FIG. 6, the front paper / PET (with a fluorescent ink printing layer on the front side / Laminated paper having a laminated structure was prepared.

When the color development luminance of the fluorescent printed pattern (star pattern) was visually determined on the laminated paper under the same conditions as in Example 1, the yellow-green emission of the star pattern was clearly visible when irradiated with ultraviolet light, and the sunlight was Since no print trace could be confirmed below, it could be confirmed that this could be a preferred embodiment of the present invention. In addition, this laminated paper had good suitability for various printings such as lithographic offset printing and suitability for a thermal transfer printer.

[0030]

According to the anti-counterfeit sheet of the present invention, the fluorescent printing ink does not exist at all on the paper surface, and paper or a coating layer having excellent printability can be used for the front and back layers.
Trouble in the process and printing during normal printing, laser printer, thermal transfer printer, etc.
No appearance defect due to transfer of the printing surface or uneven absorption occurs.

Further, since the fluorescent printing pattern is provided inside the sheet, and the expensive fluorescent ink is used only for the pattern printing portion, a forgery prevention sheet which is low in cost and excellent in the forgery prevention effect is provided. be able to.

The anti-counterfeit sheet of the present invention can be easily authenticated by ordinary people by visually confirming the fluorescent color of the printed pattern inside the sheet from both front and back sides under ultraviolet irradiation conditions using black light or the like. Can be determined,
In addition, since no traces of fluorescent printing can be recognized under sunlight, not only those requiring a high degree of authenticity such as banknotes, but also, for example, in order to prevent imitation of brands in clothing and ornaments, The present invention can also be suitably applied to a use in which a logo, a character, or the like that recognizes a brand is fluorescently printed and used as a label for a tag.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a structure of a forgery prevention sheet according to an embodiment of the present invention.

FIG. 2 is a table showing the results of observing the fluorescent printing ink layer of the forgery prevention sheet of FIG. 1 at the time of ultraviolet irradiation from both front and back surfaces and under each condition under sunlight.

FIG. 3 is a diagram schematically illustrating a structure of a forgery prevention sheet according to another embodiment of the present invention.

FIG. 4 is a diagram schematically illustrating the structure of a forgery prevention sheet according to a comparative example.

FIG. 5 is a view schematically showing a structure of a sheet for preventing forgery according to still another embodiment of the present invention.

FIG. 6 is a view schematically showing a structure of a forgery prevention sheet according to still another embodiment of the present invention.

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Claims (6)

[Claims] 1. A printing layer comprising a multilayer structure of at least three or more layers, wherein the opacity of both outer layers is in the range of 20 to 92%, and a printing layer using a fluorescent pigment inside at least one of the outer layers. A forgery prevention sheet, characterized in that a sheet is provided. 2. The forgery prevention sheet according to claim 1, wherein the opacity of both outer layers is in the range of 40 to 92%. 3. A method in which a paper layer having an opacity in the range of 20 to 92% is provided on both sides of a base material, and a printing layer using a fluorescent pigment is provided on the back side of at least one of the paper layers. Features a forgery prevention sheet. 4. A printed layer using a fluorescent pigment is provided on at least one surface of a substrate, and a coating layer having an opacity in the range of 20 to 92% is provided on both sides thereof. Anti-counterfeit sheet. 5. A printed layer using a fluorescent pigment is provided on at least one surface of a substrate, and a paper layer having an opacity in the range of 20 to 92% is provided on both sides thereof. Anti-counterfeit sheet. 6. The anti-counterfeit sheet according to claim 3, wherein the substrate is made of any one of paper, film, woven fabric and non-woven fabric, or a laminate thereof.