Recording medium for preventing leakage of printed matter

Abstract

This invention relates to a recording medium for preventing print leakage, comprising a substrate and a detection layer, wherein the detection layer comprises components dispersed and incorporated into the interior of the substrate and satisfying (1) 0.5 cm ≤ length ≤ 1.0 cm; (2) 200 < length / section diameter < 2000; and (3) 0.3 cm ‑1 <Curvature (K) < 3.0cm ‑1 The conditions for microfilaments, and per 100cm 2 The recording medium contains 30 to 300 microfilaments. As needed, the detection layer satisfies the condition (4) that the distance between the microfilaments in the closest position is <3.0 cm.

Description

Technical Field

[0001] This invention relates to a recording medium for preventing leakage of printed materials. Background Technology

[0002] With the increasing need for controls on the removal of storage media and printed documents, attempts are being made to prevent the removal of security documents by adding detection materials to the recording media. One method involves installing detection gates at entrances and exits. When a security document containing detection materials passes through the gate, it is detected, and an alarm signal is emitted to prevent its removal. Magnetic materials are used as detection materials, and electromagnetic (EM) security gates that detect this magnetic material are installed at the entrances and exits.

[0003] Long strip security paper is generally easily identifiable to the naked eye due to its size (typically about 20 μm thick, 0.65–1.0 mm wide, and 3–5 cm long). Therefore, to prevent visual detection, Korean Patent Publication No. 2008-0107977 proposed introducing a shielding layer. However, manufacturing security paper with an introduced shielding layer requires additional processes such as coating, printing, and lamination, which complicates the manufacturing process and increases manufacturing costs.

[0004] In the case of long strip security paper, multiple strips are inserted into a single A4 sheet (usually around two due to the high cost of the detection material). However, it is well known that in EM security gates, the detection strength varies depending on the orientation of the security paper. Specifically, the detection strength is strongest when the length of the detection material is perpendicular to the gate's passage direction, and becomes very weak when parallel. This phenomenon can also reverse depending on the gate's orientation. Therefore, using two to three strips inserted in any direction cannot guarantee a sufficiently high level of detection strength in all directions.

[0005] Furthermore, in the case of strip-shaped security paper, the number of strips is small and their size is large, making them easy to remove. If the detection material is removed after printing, it loses its function as security paper. An improvement to this is microfilament-type security paper, which typically inserts up to approximately 1,000 microfilaments with a diameter of about 15–20 μm and a length of 5–10 mm into an A4-sized sheet of paper. Because hundreds of microfilaments are dispersed within a single A4 sheet, they have the advantage of being difficult to remove.

[0006] The production of microfilament security paper utilizes papermaking machines, the same equipment used in the production of regular photocopy paper. On this production equipment, microfilaments tend to align more in the MD direction (machine direction, typically the longitudinal direction of A4 paper, 297mm) than in the CD direction (perpendicular to the machine direction, generally the horizontal direction of A4 paper, 210mm) (MD / CD = 9 / 1 to 7 / 3). Therefore, to maintain a high level of detection in all directions within a directional EM security door, production needs to be based on the number of microfilaments in the CD direction of the security paper. However, in this case, more microfilaments are inserted in the MD direction (longitudinal direction) of the security paper than required, increasing manufacturing costs and necessitating improvement. Summary of the Invention

[0007] Technical issues

[0008] In order to overcome the technical limitations of the prior art, one object of the present invention is to provide a recording medium for preventing the leakage of printed materials, which has excellent detection and sensing capabilities in electromagnetic security doors by using microfilament-type detection materials.

[0009] Another object of the present invention is to provide a recording medium for preventing the leakage of printed materials, which not only has excellent detection and sensing capabilities in electromagnetic security doors, but also has excellent recognition rates in security printers.

[0010] Methods for solving problems

[0011] The inventors have discovered that when using a microfilament-type detection material to replace the elongated detection material used in conventional techniques, and when used in a curved shape (i.e., an arc shape), it not only exhibits superior detection sensing ability in electromagnetic security gates but also demonstrates excellent recognition rate in security printers, thus completing this invention. Therefore, the method for solving the problem of this invention is as follows:

[0012] 1. A recording medium for preventing print leakage, comprising a substrate and a detection layer, wherein the detection layer comprises microfilaments dispersed and incorporated into the interior of the substrate and satisfying the following conditions (1) to (3),

[0013] (1) 0.5cm ≤ filament length ≤ 1.0cm,

[0014] (2) 200 < length of microfilament / cross-sectional diameter of microfilament < 2000, and

[0015] (3) 0.3cm -1 The curvature (K) of the microfilament is less than 3.0 cm. -1 ,

[0016] Furthermore, every 100cm 2 The recording medium contains 30 to 300 microfilaments.

[0017] 2. In the above-mentioned 1, the microfilaments contained in the detection layer of the recording medium for preventing leakage of printed materials shall satisfy the conditions of (1) to (3) by more than 70%.

[0018] 3. The recording medium for preventing leakage of printed materials as described in 1 or 2 above shall have a detection layer that meets the following condition (4):

[0019] (4) The distance between the microfilaments that are closest to each other is <3.0cm.

[0020] 4. The recording medium for preventing leakage of printed matter as described in 1 above, wherein the microfilament comprises a metal core and an insulating layer coated on the metal core.

[0021] 5. The recording medium for preventing leakage of printed materials as described in 4 above has an insulating layer made of glass with a thickness of 0.5 to 3.0 μm.

[0022] 6. The recording medium for preventing leakage of printed materials as described in 4 above has a metal core containing Co, Fe, Cr, Si, and B.

[0023] 7. The recording medium for preventing print leakage of the above-mentioned 1 further includes a layer of substrate without microfilaments mixed in on one or both sides of the detection layer.

[0024] 8. The recording medium for preventing leakage of printed matter as described in 7 above is a laminated form consisting of two or more layers of paper, each having a substrate layer without microfilaments mixed in on one side of the detection layer, and an adhesive layer, which are stacked together to form four or more layers of paper.

[0025] 9. The recording medium for preventing leakage of printed matter as described in 8 above, wherein the adhesive layer is laminated in such a way that it contacts the surface of the detection layer of the two-layer paper.

[0026] 10. The recording medium for preventing leakage of printed matter as described in 1 or 2 above, wherein the detection layer comprises microfilaments with a curvature angle of 0.3 to 1.5 radians.

[0027] Invention Effects

[0028] According to the present invention, a recording medium for preventing print leakage and a method for manufacturing the same are provided. The recording medium for preventing print leakage includes a substrate and a detection layer. The detection layer includes microfilaments dispersed and incorporated into the interior of the substrate and satisfying the conditions (1) to (3) above, and per 100 cm 2 The recording medium contains 30 to 300 microfilaments.

[0029] The recording medium for preventing leakage of printed materials involved in this invention uses a microfilament-type detection material with a curved shape (arc shape), thereby ensuring excellent detection sensing capability in electromagnetic security doors.

[0030] Furthermore, in this invention, each microfilament satisfying the range of conditions (1) to (3) above is made to be less than a certain distance, thereby ensuring excellent detection and sensing capabilities in electromagnetic security doors and excellent recognition rates in security printers. Therefore, compared with conventional security paper, the ability to prevent printed documents from being taken out is further improved. Attached Figure Description

[0031] Figure 1a and 1b The diagram illustrates the method for calculating the curvature (K) of a microfilament.

[0032] Figure 2 The illustration shows the detection sensing capability based on the curvature (K) of microfilaments in an electromagnetic security door.

[0033] Figure 3a and 3b The illustration shows the plane of the paper orientation during a test to prevent leakage of an A4-sized printed document into a single-person security door using an electromagnetic (EM) method. Detailed Implementation

[0034] This invention relates to a recording medium for preventing print leakage, the recording medium comprising a substrate and a detection layer, the detection layer comprising microfilaments dispersed and incorporated into the interior of the substrate and satisfying the following conditions (1) to (3).

[0035] (1) 0.5cm ≤ filament length ≤ 1.0cm,

[0036] (2) 200 < length of microfilament / cross-sectional diameter of microfilament < 2000, and

[0037] (3) 0.3cm -1 The curvature (K) of the microfilament is less than 3.0 cm. -1 ,

[0038] Furthermore, every 100cm 2 The recording medium contains 30 to 300 microfilaments.

[0039] In this invention, "recording medium for preventing leakage of printed materials" refers to "electronic induction security paper" among the types of security paper. Security paper is broadly classified into "electronic induction security paper," "anti-copying security paper," and "anti-counterfeiting security paper." "Electronic induction security paper" is a type of printing paper designed to detect and trigger an alarm when printed materials are leaked, using electronic induction doors (EM doors) installed at entrances and exits. "Anti-copying security paper" is a type of printing paper designed to create an image different from the original when copying it, allowing anyone to easily distinguish between the original and the copy. "Anti-counterfeiting security paper" is a type of paper that, while not outwardly exhibiting any special characteristics, can be distinguished from counterfeit documents using special lighting or developing methods.

[0040] The printout leakage prevention system mainly consists of security paper and a security door, with a security printer optional. The security printer is a printer that only identifies and prints security paper, not regular paper. When an organization or group wishing to prevent printout leakage uses only security paper, even if someone tries to secretly take confidential documents using a regular printer, the security door will detect it, preventing the leakage of important documents. However, this security door is ineffective if someone tries to take confidential documents out by secretly bringing in regular paper, printing it in a regular printer, and then taking it out. Therefore, to completely prevent printout leakage, it is preferable to construct a printout leakage prevention system together with a security printer. Therefore, according to the printout leakage prevention system, it is further preferable that the recording medium used for printout leakage prevention has high detection sensitivity in the security door and high recognition rate in the security printer.

[0041] With the same length of detection material, increasing its cross-sectional area increases the potential (e≒NBAf), i.e., the magnitude of harmonic components. Therefore, the larger the total cross-sectional area of ​​the detection material mixed in the detection layer (cross-sectional area of ​​one microfilament × total number of microfilaments / A4), the more advantageous it is. In the recording medium for preventing print leakage involved in this invention, when multiple microfilaments are introduced into an A4 sheet of paper in any direction, every 100cm 2 The number of microfilaments in the recording medium is preferably 30 to 300. If each 100 cm... 2 If the number of microfilaments is less than 30, the detection power is low. If it is greater than 300, the detection power is high, but the amount of microfilaments used increases, leading to increased costs. It also affects the basic color of the paper and reduces its whiteness, which is undesirable.

[0042] In the recording medium for preventing leakage of printed materials according to the present invention, the detection layer contains microfilaments as detection material that satisfy the characteristics of (1) to (3) above, and thus can exhibit the level of sensing power required in electromagnetic security doors. Hereinafter, the conditions of (1) to (4) above will be specifically explained.

[0043] (1) Length of microfilaments

[0044] In the recording medium for preventing print leakage according to this invention, the detection layer comprises microfilaments with a length of 0.5 cm or more and 1.0 cm or less. If the length of the microfilaments is less than 0.5 cm, the demagnetizing effect increases, and the recognition rate in the security printer decreases. If the length of the microfilaments is greater than 1.0 cm, the microfilaments become less dispersed and aggregate during the manufacture of the security recording medium, resulting in a lower yield and a higher price, which is undesirable.

[0045] (2) The ratio of the length of the microfilament to the cross-sectional diameter of the microfilament

[0046] In the recording medium for preventing print leakage according to this invention, the detection layer comprises microfilaments satisfying the condition 200 < filament length / cross-sectional diameter < 2000. When the microfilaments meet this condition, excellent sensing performance in EM security gates can be ensured. When the value of microfilament length / microfilament cross-sectional diameter is less than 200, the demagnetizing effect is large and the sensing power is weakened; when this value is greater than 2000, the microfilament diameter is too small, resulting in decreased productivity in the manufacturing process, and due to technical difficulties, it is difficult to stably maintain the magnetism of the recording medium, thus making it difficult to ensure the quality as a sensing / identification sensor.

[0047] When the ratio of microfilament length to microfilament cross-sectional diameter is less than 200, not only does the demagnetizing effect increase, but the thickness (total diameter) of the microfilament is also large relative to the overall thickness of the recording medium. This increases the tendency for the microfilament to protrude from the surface of the recording medium, negatively impacting smoothness. Furthermore, there is a concern that the protruding microfilament may cause skin irritation. To completely prevent the microfilament from protruding from the recording medium surface, a sandwich structure can be manufactured. Considering this, the aforementioned thickness ratio is preferably less than 0.4. On the other hand, current manufacturing techniques make it difficult to uniformly manufacture microfilaments with a ratio less than 0.1, and there is a tendency for a sharp decrease in the magnetic properties required for the detection material, which is undesirable. Therefore, the ratio of microfilament thickness (total diameter) to the thickness of the recording medium is preferably 0.1 to 0.4.

[0048] (3) Curvature and curvature angle of the microfilament

[0049] In the recording medium for preventing print leakage according to the present invention, the detection layer contains a layer that meets the requirement of 0.3 cm. -1 The curvature (K) of the microfilament is less than 3.0 cm. -1 Microfilaments under certain conditions.

[0050] The magnetic properties of magnetic detection materials largely depend on their composition, but even with the same composition, they can change depending on the shape of the magnetic material. In particular, the demagnetizing effect is highly sensitive to the shape of the magnetic material. If a slender magnetic material is placed in a magnetic field along its length, the demagnetizing effect is very small, but if the shorter side is placed along the direction of the magnetic field, the demagnetizing effect becomes very large. This means that when a magnetic field is applied to a magnetic material from the outside, the actual magnetic field sensed by the material changes significantly depending on its shape and orientation. Therefore, in EM-type security doors, there is a significant deviation in sensing power due to the length-directionality of the detected material.

[0051] The printing leakage prevention recording medium is produced using a paper mill manufactured by a paper company. Essentially, in paper produced by this mill, cellulose or other long, strip-shaped additives tend to align in the MD direction (longitudinal direction). Therefore, security paper can only ensure excellent sensing capability by producing it with a specific number of microfilaments in the CD direction (transverse direction). However, this results in inserting more microfilaments in the MD direction than necessary, significantly increasing the unit price of the product. In this invention, microfilaments arranged at an angle of less than 45 degrees to a straight line parallel to the longitudinal direction of the recording medium are referred to as MD-direction microfilaments, and microfilaments arranged at an angle of 45 degrees or more are referred to as CD-direction microfilaments.

[0052] If the MD / CD ratio of the detection material can be improved during the production of recording media using a paper machine, the problem of detection perception deviation based on the directionality of the detection material can be solved. However, it is difficult to improve the MD / CD ratio without improving the process equipment. Therefore, in this invention, a security recording medium is manufactured using an existing paper machine, and the microfilaments used as the detection material are curved, i.e., arc-shaped microfilaments, thereby solving the directionality problem in EM-type security doors.

[0053] [Formula 1]

[0054]

[0055] like Figure 1a As shown in Equation 1 above, the curvature (K) of a circle can be calculated from the length of its radius. Figure 1a In this context, if P and P' are referred to as the two ends of the microfilament, then Δs corresponds to the length of the microfilament, and Δθ corresponds to the curvature angle (radians). Figure 1b An example is shown where the diameter is measured to calculate the curvature of the microfilaments in the recording medium.

[0056] In this invention, the detection layer contains microfilaments with a curved shape, specifically, satisfying a length of 0.3 cm. -1The curvature (K) of the microfilament is less than 3.0 cm. -1 The condition of the microfilament is to minimize the sensing bias caused by directionality in the EM-type security door. If the curvature of the microfilament is less than 0.3 cm... -1 If the curvature effect is low, it can hardly improve the directionality problem in security doors. If the curvature of the microfilament is greater than 3.0 cm... -1 While there is no directional problem, the overall sensing ability will decrease sharply, making it unable to function properly as a detection material. This seems to be due to the sudden increase in the demagnetization effect.

[0057] In the recording medium for preventing print leakage according to the present invention, the detection layer may contain microfilaments with a curvature angle of 0.3 to 1.5 radians. In Equation 1 above, the curvature angle (Δθ) is a value calculated by multiplying the curvature by the length of the microfilament, representing the difference in angles between the two ends of the bent microfilament. If the curvature angle of the microfilament is less than 0.3 radians, the curvature effect is low and can hardly improve the directionality problem in the security door. If the curvature angle of the microfilament is greater than 1.5 radians, although there is no directionality problem, similar to the case of excessive curvature, the function as a detection material may be reduced due to the increased demagnetization effect.

[0058] In this invention, in order to achieve good detection in electromagnetic (EM) security gates and normal recognition in security printers, the recording medium for preventing print leakage preferably contains at least a portion, preferably more than 70%, of microfilaments that satisfy the conditions (1) to (3) above. It is possible for 100% of the microfilaments to satisfy the conditions (1) to (3) above, but in this case, the manufacturing cost may increase excessively, and the microfilament manufacturing process may also include microfilaments that cannot all satisfy such conditions. Furthermore, if more than 70% of the microfilaments included as the detection material satisfy the above conditions, detection can be performed within the error range of the security gate. Therefore, it is acceptable even if the total microfilaments included in the recording medium for preventing print leakage according to this invention contain more than 30% microfilaments that do not satisfy one or more of the conditions (1) to (3) above.

[0059] In this invention, the microfilaments described above can be any type of microfilament manufactured by any method, provided that the conditions (1) to (3) above are met. Examples of such microfilaments include in-rotating-water quenching, cold drawing, melt extraction, quenching-and-drawing, Taylor-Ulitovsky, and Adar-Bolotinsky methods, but are not limited to these methods.

[0060] (4) Distance between microfilaments

[0061] In a specific example of the printing leakage prevention recording medium of the present invention, the distance between the closest microfilaments in the detection layer can be less than 3.0 cm. This is because if the distance between the microfilaments is greater than 3.0 cm, there is a tendency for the recognition rate in the security printer to decrease. Therefore, in the case where the printing leakage prevention system includes a security printer, in order to ensure the recognition rate in the security printer, it is preferable to further satisfy the condition (4) above.

[0062] While the magnetic properties of the detection material are important in security gate sensing, the presence of a specific identifiable metal is crucial for the recognition rate in security printers. Although magnetic recognition methods could be implemented in security printers, this would increase costs and complicate the equipment configuration. Therefore, commercially available security printers currently primarily employ metal detection methods.

[0063] In this invention, the microfilament may comprise a metal core and an insulating layer coated on the metal core. The metal core may comprise Co, Fe, Cr, Si, and B, and the insulating layer may be made of glass with a thickness of 0.5 to 3 μm. In this invention, by comprising Co, Fe, Cr, Si, and B in the metal core constituting the microfilament, the required detection force in security doors and the recognition rate in security printers can be ensured.

[0064] In this invention, the cross-sectional diameter of the microfilament refers to the diameter of the magnetic metal core, and the thickness of the microfilament refers to the overall diameter including the metal core and the insulating layer.

[0065] The recording medium for preventing print leakage according to the present invention may further include a substrate layer without microfilaments on one or both sides of the detection layer. Alternatively, the recording medium for preventing print leakage according to the present invention may be a laminate of four or more layers of paper, consisting of two or more layers of paper having a substrate layer without microfilaments on one side of the detection layer, separated by an adhesive layer. In this case, the adhesive layer may be configured to contact the surface of the detection layer of the two paper layers.

[0066] The basis weight (weight per unit area) of the recording medium for preventing print leakage involved in this invention is 30 to 100 g / m² based on the final product (including a single-layer paper consisting only of a substrate and a detection layer in which microfilaments are mixed in, a two-layer paper having a substrate layer without microfilaments on one side of the detection layer, a multilayer paper consisting of four or more layers of the two-layer paper stacked together, or a three-layer paper having substrate layers without microfilaments on both sides of the detection layer).2 Scope. The recording medium for preventing print leakage involved in this invention essentially corresponds to printer paper, and therefore preferably has a basis weight similar to existing commercial printer paper. If the basis weight is less than 30 g / m³ 2 If the basis weight is higher than 100 g / m³, it will be difficult to manufacture paper in a form containing microfilaments, and it will be too thin to be useful. 2 This increases manufacturing costs, reduces usability due to excessive thickness, and lowers print quality.

[0067] The printing leakage prevention recording medium according to this invention can be manufactured using papermaking machines from paper companies equipped with four-wire papermaking machines, cylinder papermaking machines, and combined papermaking machines, and can be manufactured, for example, by the method described in Korean Patent Publication No. 2017-0053027. When using a combined papermaking machine, two, three, or four layers of paper can be manufactured in one operation, in which case at least one layer becomes a detection layer containing microfilaments as a detection material. Furthermore, the paper manufactured by the aforementioned papermaking machine can be used as a base paper (substrate) and a laminator can be used to manufacture the final recording medium. A laminator is a device that manufactures a final product by laminating another base paper after applying an adhesive to one side of the base paper. The two base papers can be of the same type or different types. That is, when there are two base papers, each can be one or more layers of paper with or without microfilaments. For example, if one base paper is a two-layer paper consisting of a substrate mixed with microfilaments (i.e., the detection layer) and a substrate without microfilaments, and another base paper is a one-layer paper consisting of a substrate without microfilaments, the final product can be a three-layer paper.

[0068] The recording medium for preventing leakage of printed matter involved in this invention is basically the same as the copy / printing paper for printers. Therefore, the material of the substrate can be offset paper that occupies most of the copy paper regardless of whether microfilaments are mixed in, or it can be thin paper with a composition similar to offset paper.

[0069] The lamination pattern of the final product does not affect the detection capability of the recording medium for preventing print leakage in security doors or the recognition rate in security printers. However, it is advantageous from the perspective of not causing skin irritation due to microfilament protrusion when the recording medium for preventing print leakage consists of three or more layers of paper, at least one of the inner layers is a detection layer incorporating microfilaments into the substrate, and the two outermost sides of the recording medium are composed of substrate layers without microfilaments.

[0070] Example

[0071] The present invention will now be described in more detail through embodiments. However, these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention to the scope of the embodiments.

[0072] Examples 1 to 13

[0073] Microfilaments comprising a metal core in the form of an amorphous alloy containing Fe, Co, Cr, B and Si with a cross-sectional diameter of 5 to 25 μm and an insulating layer of glass material (silicon dioxide) with a thickness of 0.5 to 3 μm are manufactured by a modified / corrected Taylor-Ulitovsky method, and then microfilaments having the values ​​shown in Table 1 below are prepared under conditions (1) to (3).

[0074] The prepared microfilaments are mixed with a pulp suspension and paper is formed using a paper machine equipped with a two-wire paper machine, a cylinder paper machine, or a combination of paper machines, by a known method (e.g., the method described in Korean Patent Publication No. 2017-0053027), thereby producing paper with a final basis weight of 80 g / m³. 2 The recording media of Examples 1 to 13, where condition (4) has the values ​​shown in Table 1 below.

[0075] Comparative Examples 1 to 15

[0076] Conditions (1) to (4) are made to have the values ​​shown in Table 1 below. Otherwise, the recording media of Comparative Examples 1 to 15 are manufactured by the same method as in Example 1.

[0077] [Table 1]

[0078]

[0079] Explanation of conditions (1) to (4)

[0080] (1) Length of the microfilament (Δs)

[0081] (2) Length of microfilament / cross-sectional diameter of microfilament

[0082] (3) Curvature (K) of the microfilament

[0083] (4) The distance between the microfilaments that are closest to each other (A4 reference)

[0084] Curvature angle (radians, Δθ) = KxΔs; curvature K = Δθ / Δs = Δθ / RΔθ = 1 / R

[0085] Examples 14 to 16 and Comparative Examples 15 to 17

[0086] Recording media satisfying the conditions shown in Table 2 below were manufactured using the microfilaments (microfilament A) used in Examples 1, 2 and 5 to 7 and the microfilaments (microfilament B) used in Comparative Examples 1, 5, 9, 12 and 13.

[0087] [Table 2]

[0088]

[0089] Experimental Example

[0090] The evaluation results of the following items performed on Examples 1 to 16 and Comparative Examples 1 to 17 are shown in Table 3.

[0091] 1. Security gate detection and sensing capabilities

[0092] The sensitivity of the recording medium was tested when it passed through two types of electromagnetic gates (a single-mode EVOLVEEM system manufactured by Checkpoint and a dual-mode EM system manufactured by SSLT), and the sensitivity was expressed using a 5-point method. A higher value indicates higher sensitivity, with X representing a situation where the gate cannot detect the medium. In Table 3, when representing the paper plane, uppercase letters indicate the paper's longitudinal direction (297 mm for A4 paper), and lowercase letters indicate the paper's transverse direction (210 mm for A4 paper). Figure 3 illustrates the paper-oriented planes during the detection test of recording media to prevent leakage of A4-sized printed materials through a single-person security gate using electromagnetic (EM) methods (Zx plane: when passing through with the A4 paper longitudinally concealed in front of the chest; Zy plane: when passing through with the A4 paper longitudinally tucked under the armpit).

[0093] 2. Security printer recognition rate

[0094] The extent to which the recording medium was identified as security paper and actually printed was determined when printing in a security printer (CLP-755N_M fine laser printer manufactured by Creat), and the recognition strength was expressed using a 5-point method (the higher the value, the higher the recognition strength).

[0095] 3. Whiteness

[0096] For a portion of the paper, measurements were taken using the eXact measuring instrument from X-rite Corporation, USA. A higher measurement value indicates that the paper appears whiter to the naked eye.

[0097] [Table 3]

[0098]

[0099] According to Table 3 above, the recording media for preventing print leakage in Examples 1 to 13, which meet the values ​​of conditions (1) to (3) within the scope of the present invention, exhibit excellent sensing power in electromagnetic security doors. Examples 1 to 12 also meet condition (4), where the distance between the microfilaments at the closest positions is <3.0 cm, thus demonstrating excellent recognition power in security printers. Comparative Examples 1 to 14 show that the distance between the microfilaments at the closest positions is <3.0 cm per 100 cm. 2 The conditions of 30 to 300 microfilaments in the recording medium and the situation where one or more of conditions (1) to (3) are outside the scope of the present invention confirm that the detection sensing power in the security door is insufficient or the whiteness is as low as less than 110, making it unsuitable as a recording medium for printing paper (copy paper) and for preventing leakage of printed matter.

[0100] Comparative Example 4 used a microfilament with a length of 1.5 cm, meaning that condition (1) exceeded the upper limit of the present invention. Therefore, the dispersion was poor when manufacturing the security recording medium, and the retention rate was as low as less than 60% due to removal during the selection process (the retention rate was 80-95% when the length of the microfilament was less than 1.0 cm). Therefore, the unit price increased more than that of the longer portion. In terms of physical properties, the sensing power was better in the dual-mode EM door, but the sensing power of the Zx plane in the single-mode security door was as low as the average level. This seems to be because although the curvature met the range of the present invention, the length was too long and the curvature angle became larger (2.143), resulting in an increased demagnetization effect (the curvature angles of Examples 1 to 12 were all less than 1.5 (0.31-1.48)).

[0101] In Comparative Examples 1, 5, and 9, condition (1) exceeded the lower limit of the present invention. It can be seen that when the length of the microfilament is less than 0.5 cm, even if condition (2) (Comparative Example 1) is met, the sensing power in the security door is very low. It can be seen that although the aspect ratio of the microfilament is important, only when it is basically above the minimum length can excellent results be obtained in EM-type sensing.

[0102] In Comparative Example 3, condition (3) exceeded the upper limit of the present invention (curvature 3.45 cm). -1 Regardless of the curvature effect of the microfilaments, their function as a detection material is reduced, leading to a rapid decline in sensing capability. Analysis revealed that a demagnetizing effect also exists when the curvature angle is above 2.

[0103] Comparative Examples 8, 10, 12, 13 and 14 are cases where condition (3) exceeds the lower limit of the present invention (Comparative Examples 12 to 14 use microfilaments with a straight shape), confirming that the directional problem in the security door is not improved due to the low or no curvature effect.

[0104] Comparative examples 2 and 7 are per 100cm 2When the number of microfilaments is less than 30, they are almost not detected in the EM gate due to insufficient number of microfilaments. In addition, the distance between the microfilaments at the closest position in the detection layer (condition (4)) exceeds 3.0 cm. Due to the large distance between the microfilaments, the probability of the security printer's recognition sensor recognizing this in a short time is reduced, and there is a possibility that it cannot be recognized as security paper.

[0105] Comparing Examples 6 and 11 per 100cm 2 The number of microfilaments is more than 300. Although the sensing ability in security doors or the recognition ability in security printers are excellent, the whiteness is less than 110, and the use of too many microfilaments leads to an increase in unit price.

[0106] On the other hand, Examples 14 to 16 are recording media containing more than 70% of microfilaments that satisfy the conditions (1) to (3) above, demonstrating excellent sensing power in EM-type security gates and recognition power in security printers. In contrast, Comparative Examples 15 to 17 are recording media containing more than 30% of microfilaments that do not satisfy any one of (1) to (3) above, demonstrating insufficient sensing power in EM gates.

[0107] As described above, the recording medium for preventing leakage of printed materials involved in this invention improves the directionality problem in electromagnetic security doors by using a large number of curved, i.e., arc-shaped detection microfilaments, thereby enhancing the sensing power in the security door.

Claims

1. A recording medium for preventing print leakage, comprising a substrate and a detection layer, said detection layer comprising microfilaments dispersed and incorporated into the interior of the substrate and satisfying the following conditions (1) to (3), (1) 0.5 cm ≤ filament length ≤ 1.0 cm, (2) 200 < filament length / filament cross-sectional diameter < 2000, and (3) 0.3 cm -1 The curvature K along the length of the microfilament is less than 3.0 cm. -1 , Furthermore, every 100cm 2 The recording medium contains 30 to 300 microfilaments.

2. The recording medium for preventing leakage of printed matter according to claim 1, wherein more than 70% of the microfilaments contained in the detection layer satisfy the conditions of (1) to (3).

3. The recording medium for preventing print leakage according to claim 1 or 2, wherein the detection layer satisfies the following condition (4): (4) The distance between the microfilaments that are closest to each other is < 3.0 cm.

4. The recording medium for preventing print leakage according to claim 1, wherein the microfilament comprises a metal core and an insulating layer coated on the metal core.

5. The recording medium for preventing leakage of printed matter according to claim 4, wherein the insulating layer is made of glass and has a thickness of 0.5 to 3.0 μm.

6. The recording medium for preventing leakage of printed matter according to claim 4, wherein the metal core contains Co, Fe, Cr, Si and B.

7. The recording medium for preventing print leakage according to claim 1, wherein one or both sides of the detection layer further comprises a layer of substrate without microfilaments mixed in.

8. The recording medium for preventing leakage of printed matter according to claim 7 is a laminated form consisting of two or more layers of paper, each having a substrate layer without microfilaments on one side of the detection layer, laminated with an adhesive layer, comprising four or more layers of paper.

9. The recording medium for preventing print leakage according to claim 8, wherein the adhesive layer is laminated in such a manner that it contacts the surface of the detection layer of the two layers of paper.

10. The recording medium for preventing print leakage according to claim 1 or 2, wherein the detection layer comprises microfilaments with a curvature angle of 0.3 to 1.5 radians in the length direction.

Images