KR100603103B1 - Specific security thread and security papers using the same - Google Patents

Abstract

At least one transparent film layer and at least one near-infrared absorbing layer, the near-infrared absorption layer is characterized in that the anti-counterfeiting hidden line is characterized in that it reflects light in the visible region and absorbs light in the near infrared region. In the visible region, the presence of the near infrared absorbing layer is unknown, but the near infrared absorbing layer appears black in the near infrared region due to the near infrared absorption characteristic. When the hidden line is concealed or partially exposed in the security sheet, the near infrared irradiation of the IR spectrophotometer enables identification of the inclusion of the hidden line, thus acting as a security element to prevent the forgery of important documents.

Documents, Identification, and Device Reading

Description

Special security thread and security papers using the same}

1 is a clear text type hidden line and a cross-sectional view thereof according to the prior art,

2 is a cross-sectional view of a hidden line according to an embodiment of the present invention,

3 is a cross-sectional view of a hidden line according to another embodiment of the present invention,

4 is a cross-sectional view of a hidden line according to another embodiment of the present invention;

5 is a plan view of a hidden line according to another embodiment of the present invention,

6 is a plan view of a hidden line according to another embodiment of the present invention.

The present invention relates to a silver wire having an absorption characteristic in the near infrared region and a security paper using the same, and more particularly, by including a near infrared absorbing layer that reflects light in the visible region and absorbs light in the near infrared region. The present invention relates to a hidden line functioning as a security element and a security sheet using the same.

In the manufacture of securities such as banknotes and checks, hidden lines have been inserted in the form of total concealment or partial exposure inside the paper to prevent counterfeiting.

British Patent Publications 152853 and 1446446 disclose a technique for preventing forgery by inserting a hidden wire into the paper or by utilizing it in the form of partial exposure.

U.S. Pat.Nos. 5314739 and 5419424 describe silver lines of a printing method in which fine colors or black letters or patterns are printed on transparent films, or silver lines additionally treated with special pigments having ultraviolet light emission characteristics. have.

US Patent No. 4652015 and European Publication No. 0319157 disclose a clear text type hidden line in which a metal deposition layer is coated on a transparent film and then selectively removed so that letters or patterns appear transparent. 1).

In addition to this, there are silver wires produced by applying various elements such as electrical conductivity, magnetic properties, hologram characteristics, and color conversion to a film having a transparent film or a metal layer.

The hidden lines are narrowly cut into a narrow width of about 0.5 mm to 5 mm, and then inserted into the paper when the security paper is manufactured and used as an anti-counterfeiting element, thus occupying a very important position as a security element.

However, forgery of security paper such as securities is frequently generated due to the continuous improvement of personal computer and the development of prints.

For example, in the case of silver wire printed with colored or black letters on a transparent film and printed with special pigments having fluorescence properties, special pigments having fluorescence properties are produced and sold by general pigment companies to maintain security and prevent counterfeiting. There is a problem that cannot be obtained.

As another example, in the case of clear text-type hidden wires used in recently issued Euro banknotes (see FIG. 1), counterfeits in counterfeits in a similar form are distributed in Korea, thereby failing to function as a security element.

The goal of modern security elements is to enable authenticity assessment by identification devices as well as visual identification. In other words, due to the securities deposit and withdrawal by automated equipment, the use of vending machines, and the distribution of various security products, machine reading is essential for fast and clear authenticity assessment.

The present invention has been made to solve the above problems, and an object of the present invention is to improve the hidden line through the general level of the security element, that is, visible pigments in the visible light in the visible light area to distinguish the security element only in the near infrared It is to provide a hidden line to have.

Another object of the present invention is to provide a security paper including the hidden line.

In the case of a silver line using a general pigment or dye, only a specific wavelength of visible light reflects a certain color, but in the near infrared region, the characteristic of reflecting or absorbing all wavelengths is weak, making it difficult to distinguish a hidden line under near infrared light. Therefore, in order to create a hidden line functioning as a new security element, the light emission characteristics in the visible region and the light emission characteristics in the near infrared region are different from each other, ie, reflect or completely transmit the wavelength of the visible region and absorb the wavelength of the near infrared ray. It was found that the phosphor should be used, and the present invention was completed based on this.

The anti-counterfeiting silver line for achieving the object of the present invention comprises at least one transparent film layer and at least one near infrared absorbing layer, the near infrared absorbing layer reflects light in the visible region and absorbs light in the near infrared region It features.

In addition, the security paper for achieving the object of the present invention is characterized in that it comprises the anti-counterfeiting silver wire.

Hereinafter, the present invention will be described in more detail.

The anti-counterfeiting silver wire according to the present invention includes at least one transparent film layer and at least one near infrared absorbing layer.

Examples of the transparent film used to form the transparent film layer include polyamide resins, polyester resins, polyacrylic resins, polyvinylacetate resins, polyethylene resins, and polyvinyl chloride resins. It is preferable that the thickness of the said transparent film layer is 16-25 micrometers. When the manufactured silver wire is inserted into the security paper, since the paper of the portion where the hidden line is inserted becomes thin, a hole may be formed in the security paper of the portion where the hidden line is inserted if the thickness of the transparent film exceeds the above range. Moreover, when the thickness of a transparent film becomes smaller than the said range, there exists a problem that the intensity | strength of a transparent film becomes weak.

The near-infrared absorbing layer reflects all light in the visible region and absorbs light in the near-infrared region. Using this feature, it can be used as a counterfeit identification element of security paper in an automated device. The authenticity can be identified by checking the absorption characteristics by irradiating near-infrared radiation from the instrument. In addition, reading by an IR spectrophotometer exhibits black light emission upon near-infrared irradiation for identification.

The near infrared absorbing layer is formed by an ink composition containing a near infrared absorbing agent. The amount of the near infrared absorber in the ink composition is preferably 5 to 30% by weight. This is the amount necessary to use the absorption characteristics of the near infrared absorber as an identifying element in the IR spectrophotometer. The ink composition may include 5 to 30% by weight of the near-infrared absorbent, 60 to 70% by weight of varnish for PET, and 10 to 30% by weight of the solvent. At this time, the solvent is preferably a mixture of MEK (methyl ethyl ketone) and toluene in a ratio of 1 to 1. The ink composition may further include a general pigment in addition to the component.

Examples of the near infrared absorber include inorganic copper phosphate or iterium phosphate glass; Organic phthalocyanine and naphthalocyanine.

In the near-infrared absorption characteristics, the inorganic color is close to white in the visible region, and excellent in chemical resistance and solvent resistance, but weak in absorption strength. In the case of organic type, it is colored in hue, mainly green, blue, brown, and black color. It has weak chemical resistance and solvent resistance, but has stronger absorption strength than inorganic type. Therefore, the choice may vary depending on the situation.

The absorption wavelength in the near-infrared region is characterized in that the phosphate is 870 nm, the iterium phosphate glass is 980 nm, the phthalocyanine is 700 to 1,000 nm, and the naphthalocyanine is 700 to 1,000 nm. It is shown.

Preferably, the near-infrared absorber is 20 to 70% by weight of copper tetrafluoroborate, 80 to 30% by weight of phosphate compounds selected from the group consisting of phosphorous acid, polyphosphoric acid and phosphorus pentoxide and magnesium oxide, strontium oxide, zinc oxide, aluminum oxide and It may be used to finely granulate 10㎛ or less from those containing 1% by weight or less of metal oxide selected from the group consisting of arsenic oxide (see Patent Publication No. 2002-58117).

As a method of forming the near infrared absorbing layer, a gravure printing method and a coating method by dipping may be used.

In the gravure printing method, a method of printing an ink composition containing a near infrared absorber on a transparent film, a method of printing an ink composition containing a near infrared absorber and a black or colored pigment on a transparent film, or the one or both surfaces of the transparent film And a method of printing an ink composition. At this time, the depth of a gravure printing plate is 20-50 micrometers, Preferably it is 30-40 micrometers. This is because the near-infrared absorber has a particle size of about 3 to 10 μm so that the near-infrared absorbent can be sufficiently buried in the silver line through the gravure printing plate during printing. As the depth of the printing plate is smaller than 20 μm, it is difficult to obtain the required level of light absorption effect because the particles do not adhere well, and when the depth exceeds 50 μm, deformation of the printing plate may occur due to excessive plate making in manufacturing the gravure printing plate. In addition, in the case of a printing plate for printing a character or a pattern may be limited to the accurate reproduction of the character or pattern.

The coating method by dipping is a method of coating the front and back sides of the film at the same time by controlling the amount of coating by a pressing roll after passing the film through an immersion container containing an ink composition containing a near infrared absorber. The method may be applied when the entire film is coated, but there is a problem in partially applying an ink composition including a near infrared absorber to a character or a pattern portion. Therefore, the gravure printing method may be more usefully applied as the printing method for forming the near infrared absorbing layer.

The anti-counterfeiting silver wire according to the present invention may include at least one transparent film layer and at least one near infrared absorbing layer; Alternatively, the composition may further include at least one transparent film layer and at least one near infrared absorbing layer as an essential component layer, and further include at least one of a character pattern printing layer, an ultraviolet light emitting layer, a protective resin layer, and a metal deposition layer. At this time, the positions of the transparent film layer, the near infrared absorbing layer, the character pattern printing layer, the ultraviolet light emitting layer, the protective resin layer, and the metal deposition layer can be in various combinations.

The character-pattern printed layer provides information that can be easily visually determined whether the hidden line is included in visible light, which facilitates identification of security paper for the general public. Inks used for forming the character pattern printing layer can usually use gravure printing inks.

Since the ultraviolet light emitting layer has light emission characteristics when irradiated with ultraviolet light (wavelength 365 to 254 μm), inclusion of a hidden line may be determined by an ultraviolet light emitting device (such as a trifluoride fluorescent lamp, a VILBER LOURMAT VL-6LC). It is preferable to use pigments (LUMILUX CD-702, 704, Uksung Chemical Inorganic Phosphor, etc.) which are colorless in visible light.

The metal deposition layer may be used as a differentiation factor by the silver wire machine by providing conductivity enhancement or magnetic property of the silver wire.

The protective resin layer has an object to enhance the physical properties of the silver wire. Mainly hot melt polyethylene resins, ethylene vinyl acetate resins, polyurethane resins and the like can be used.

The security sheet according to the present invention includes the hidden line described above.

The hidden line is inserted into the security sheet in a form that is completely concealed or partially exposed.

The silver wire inserted in the said security paper can be cut | disconnected and used for the width | variety of 0.5-5 mm.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereto.

Manufacture of silver wire

Example 1

15% by weight of near-infrared absorber (55% by weight of copper tetrafluoroborate, 44% by weight phosphoric acid and 1% by weight of aluminum oxide), 70% by weight of varnish for PET (Medium for Daehan Ink Chemical Co., Ltd.), solvent is MEK (methylethyl Ketone) and toluene in a ratio of 1 to 1 by applying an ink composition containing a gravure printing method on a 25 μm transparent polyester film to a 25 μm transparent polyester film to prepare a silver line having a 3 μm thick near-infrared absorbing layer. At this time, the depth of the gravure printing plate was 35 μm (see FIG. 2).

Example 2

Ink having a green light emission characteristic in the ultraviolet region after printing black microcharacters (15-20 wt% of Neozapon Black X51 (BASF)) on a 16 μm transparent polyester film by a gravure printing method (Lumilux Green CD-702) , 12% by weight) was applied to the entire surface, and then printed on the opposite side of the transparent polyester-based film using a ink composition used in Example 1 in a gravure printing method with a thickness of 3 μm to prepare a silver wire. At this time, the depth of the gravure printing plate was 30 μm (see FIG. 3).

Example 3

A 25 μm transparent polyester film was used as a near-infrared absorber (55 wt% copper tetrafluoroborate, 44 wt% phosphoric acid, and 1 wt% aluminum oxide) 30 wt%, varnish for PET (MEDIUM for PET, Korea Ink Chemical Co., Ltd.) 60 % By weight, solvent was passed through the immersion solution containing 10% by weight of MEK (methyl ethyl ketone) and toluene in a ratio of 1 to 1 by using a compression roll to produce a silver wire having a thickness of 3 ㎛ each near-infrared absorbing layer ( See FIG. 4).

Example 4

After printing a portion of the text on a 16 μm transparent polyester film using a gravure printing method with red (PANAX Red CL-304G, 1% by weight of Uksung Chemical Co., Ltd.), a near infrared absorber (55% by weight of copper tetrafluoroborate), 44 wt% of phosphoric acid and 1 wt% of aluminum oxide) 14 wt%, red pigment (PANAX Red CL-304G, Uksung Chemical Co., Ltd.) 1 wt%, PET varnish (Daeink Ink Chemical Co., Ltd. PET MEDIUM) 70 wt% %, The solvent was printed by printing the remaining part of the letter to a thickness of 3 ㎛ using an ink composition containing 15% by weight of MEK (methyl ethyl ketone) and toluene in a ratio of 1 to 1. At this time, the depth of the gravure printing plate was 30 μm (see FIG. 5).

Example 5

The blue pattern (PANAX Blue BS-7050, Uksung Chemical Co., Ltd. 0.4 weight%) was printed on the 16-micrometer transparent polyester film by the gravure printing method. Then, on the patterned layer, a near-infrared absorber (55 wt% copper tetrafluoroborate, 44 wt% phosphoric acid and 1 wt% aluminum oxide) 14.8 wt%, black pigment (CARBON CSZ-238, CABOT) 0.2 wt%, varnish for PET (Medium ink for PET, Daehan Ink Chemical Co., Ltd.) 70% by weight, the solvent is printed to a thickness of 3㎛ using an ink composition containing 15% by weight of MEK (methyl ethyl ketone) and toluene in a one-to-one ratio To prepare a silver wire. At this time, the depth of the gravure printing plate was 40 μm (see FIG. 6).

Manufacture of security paper

Example 6

A secured paper was prepared by inserting a silver wire manufactured by Example 1 and cut into 1.2 mm width directly into a single paper by a conventional silver wire feeding method when manufacturing paper in a paper machine.

Example 7

The silver wire manufactured by Example 2 and cut into 1.5 mm width was put into paper by a conventional partially exposed silver wire manufacturing method in a ring paper machine to prepare a security paper.

Example 8

A secured paper was prepared by inserting a silver wire cut by 2 mm width cut in a 2 mm width into a double paper-based paper by a conventional silver wire feeding method when manufacturing paper in a paper machine.

Example 9

The secured paper was manufactured by directly inserting the silver wire manufactured by Example 4 and cut into a 1.5 mm width into a single paper by a conventional silver wire feeding method when manufacturing paper in a ring paper machine.

Example 10

The secured paper was manufactured by directly inserting the silver wire manufactured by Example 5 and cut off to a width of 1.5 mm by inserting the silver wire directly into the double paper using a conventional silver wire feeding method when manufacturing paper in a ring paper machine.

The visual inspection and near-infrared inspection were performed about the silver wire of Examples 1-5 and the security paper (Examples 6-10) after inserting the said silver wire into paper. As a result of visual inspection, the presence of the near-infrared absorbing layer was not found in Examples 1 to 3 printed using the ink composition containing only the near-infrared absorbent without a general pigment. In addition, in the case of Examples 4 and 5 printed using the ink composition containing a near infrared absorber and a general pigment, it was not known whether the near infrared absorber layer was present.

In the case of near-infrared inspection, experiments were performed using Datacolor's Chroma-Calc 3.2 & MF45 IR spectrophotometer and Perkin-Elmer's Lambda 9 UV / VIS / NIR spectrophotometer. At this time, the wavelength of the near infrared ray was irradiated in the 870 to 980㎛ band. As a result, the silver line of the part containing a near-infrared absorption layer was confirmed clearly as black. In Examples 1 to 3, the entire silver wire was black, and in Examples 4 and 5, only the near infrared absorbing layer of the portion where the general pigment and the near infrared absorber were mixed was clearly identified as black.

The security paper according to Examples 6 to 10 was checked for reproducibility using a color copying machine (Lotte Canon CLC1150) and a scanner (AGFA DUOSCAN, EPSON PERFECTION 2400PHOTO). As a result, the input hidden line was not confirmed at all.

As a result of confirming the security paper using the IR spectrophotometer, the portion containing the near-infrared absorber appeared in black, and the input of the hidden line was confirmed.

This characteristic of the hidden line according to the present invention shows that the applicability as a device sensing element is very good.

As described above, the silver wire according to the present invention exhibits light emission characteristics of colorless or near white color under visible light, and thus is difficult to visually identify, but in the near-infrared region, light is absorbed by using a specific device (a device capable of irradiating near infrared light). It exhibits black light emission characteristics during the inspection. Due to the characteristics of the hidden line, the security paper containing the hidden line can be identified by a reading device (a device capable of irradiating near-infrared rays as well as a device or a device capable of processing the data into data), so that important documents are forged. You can prevent it.                     

While specific embodiments of the present invention have been described above, the present invention is not limited to the above-described specific embodiments, and the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Anyone of ordinary skill in the art can make various modifications, as well as such modifications are within the scope of the claims.

Claims (10)

At least one transparent film layer; And At least one near infrared absorbing layer; The near-infrared absorption layer reflects light in the visible region and absorbs light in the near-infrared region. The anti-counterfeiting silver wire according to claim 1, wherein the transparent film layer has a thickness of 16 to 25 µm. The anti-counterfeiting silver wire according to claim 1, wherein the near infrared absorbing layer is formed of an ink composition including a near infrared absorbing agent, and the amount of the near infrared absorbing agent in the ink composition is 5 to 30% by weight. The method of claim 3, wherein the near-infrared absorbent is 20 to 70% by weight copper tetrafluoroborate, 80 to 30% by weight phosphate compound selected from the group consisting of phosphorous acid, polyphosphoric acid and phosphorus pentoxide and magnesium oxide, strontium oxide, zinc oxide, oxidation Anti-counterfeiting silver wire, characterized in that it comprises 1% by weight or less of a metal oxide selected from the group consisting of aluminum and arsenic oxide. The anti-counterfeiting hidden line according to claim 1, further comprising at least one colored, black or gray letter pattern printing layer. The anti-counterfeiting hidden line according to claim 1, further comprising at least one ultraviolet light emitting layer. The anti-counterfeiting silver wire according to claim 1, further comprising at least one protective resin layer. The anti-counterfeiting silver wire according to claim 1, further comprising at least one metal deposition layer. A security paper comprising a hidden line according to any one of claims 1 to 8. 10. The security sheet of claim 9, wherein the hidden line is cut into a width of 0.5 to 5 mm and inserted into the security sheet.

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