RU2260088C2 - Security paper protected from falsification and method for manufacturing the paper - Google Patents

Abstract

FIELD: printing engineering.

SUBSTANCE: paper is protected by introducing chemical reagents into paper and into paint applied over the paper surface. The reagents are selected in a way that they interact with each other in presence of corresponding authenticity indicator in producing colored reaction products at the places the paper and paint contact each other. Any of chemical reagents alone does not react with the indicator with colored compounds being produced.

EFFECT: high difficulty in discovering reagent complex used; reduced protection costs.

9 cl, 7 dwg

Description

The invention relates to the field of chemical protection against counterfeiting of securities and may find application in the manufacture of excise stamps, bonds, checks, tickets and other securities, the authenticity of which is constantly checked.

Known security paper containing a reaction system of color-forming and color-developing components, the interaction between which occurs when the paper and the marker come into contact with the marker fluid, which leads to a discoloration of the marker fluid (DE 3918765, 12/13/1990). The disadvantage is the ability to easily decrypt such a single-level chemical protection, in which two components react with each other without the participation of an indicator, since the marking liquid itself is a colorimetric indicator.

Known methods of chemical protection against counterfeiting of valuable types of paper, which are based on the introduction of protective chemicals (ZHR) in paper (for example, FR 2694772, 02/18/94), or in ink (for example, DE 10020873, 08/08/2001). Authentication in this case is carried out by color and color intensity of the products of the reaction of ZHR with a specific colorimetric indicator. To increase the degree of protection, several ZXR (multilevel chemical protection) is introduced into the paper. However, in spite of some complication for the fake decryption of the composition of such multicomponent SXR, the cost of such protection increases significantly.

The closest in technical essence and the achieved result is a security paper and a method for its manufacture, according to which at least two chemical reagents are selected that are selected from the conditions for providing a different-speed chemical reaction with a universal colorimetric indicator and the formation of a different color and intensity in a given period of time colorings of products to determine the degree of protection, while all color-forming components of protective chemical reagents are converted to insoluble in water form (RU 2203354, 04.21.2003).

A disadvantage of the known technical solution is the increase in the cost of such protection and the possibility of its interpretation in paper.

The aim of the present invention is to develop a method that can significantly complicate the decoding of SXR while reducing the cost of chemical protection of a security.

The problem is solved by the described security paper, protected from counterfeiting by the introduction of a protective chemical reagent, the presence of which is determined by a colorimetric indicator of authenticity, moreover, the security paper contains different chemicals in the paper and in the ink applied to the paper, which can interact with each other in the presence of a corresponding authenticity indicator with the formation of colored reaction products at the contact points of paper and paint, while each of the chemical reagents separately does not interact exists with the indicator to form a colored compounds.

The problem is also solved by the described method of manufacturing security paper, counterfeit, which includes the introduction into the paper or paper pulp of the main chemical reagent, as well as the introduction of at least one additional chemical reagent in the paint used when applied to paper, while the chemicals used choose from the calculation of ensuring the interaction of the primary and secondary reagents with each other in the presence of an appropriate colorimetric indicator of authenticity with the formation of colored reaction products and the absence of interaction of each reagent individually with this indicator of authenticity.

Chemical reagents can be introduced into the paper by surface treatment together with sizing compositions or by feeding the reagents in the form of aqueous solutions into the paper pulp, followed by precipitation on cellulose fibers by transferring into an insoluble form.

Chemical reagents are preferably introduced into a colorless or white paint in the form of aqueous or alcoholic solutions or white reactive pigments.

To mask the main protection, it is additionally possible to print on paper with reactive inks that form colored reaction products when interacting with the authenticity indicator.

The process of applying ink can be carried out on printing and / or paper equipment.

The technical result of the invention lies in the fact that the obtained multilevel chemical protection when printing a security with the appropriate selection and combination of ZHR in paper and paint, as well as in the composition of the indicator, can hardly be decrypted at a significantly lower cost compared to the well-known paper with multilevel chemical protection (due to the lower consumption of expensive ZHR when printing with inks compared with their introduction into paper). In this case, printing with water-borne colorless inks can be carried out in the process of making paper directly on a paper machine (for example, by inkjet method).

An advantage of the invention is the possibility of using the same paper for simultaneous printing with different (usually colorless) inks, which, when combined with a universal colorless indicator and paper components, form reaction products of different colors and color intensities (multilevel chemical protection). In addition, for misinformation when trying to decrypt the entire complex of ZXR, individual printing elements on paper can be performed with conventional reactive inks with ZXR, which change color when interacting with a universal indicator for this ZXR system, regardless of the composition of the paper (masking reactive inks).

The following are examples of the manufacture of a security in accordance with the claimed method with various chemicals and various colorimetric indicators.

Example 1

Paper made on a paper machine (BDM) is glued in a BDM size press with a solution of yellow blood salt (K ₄ [Fe (CN) ₆ ]) together with a sizing composition based on a neutral polymer (for example, polyvinyl alcohol) at a rate of 2-5 kg per ton of paper. In the form of an aqueous solution, yellow blood salt can be added if there is no size press directly to the paper pulp, followed by its precipitation on cellulose fibers with precipitants (for example, water-soluble nickel salts). The resulting paper on a certain part of its area is sealed with water or alcohol-borne white ink containing 10-20% of a reactive pigment based on iron phosphate III (FePO ₄ ). As a colorimetric indicator, 1-2% water-glycerin solutions of sulfuric or hydrochloric acids are used, which form a dark gray compound with a blue tint during the reaction with ZHR at the printing sites.

Example 2

The method is carried out as in example 1, but as a printing ink, a water-borne white ink is used, in which a 2-3% mixture of iron sulfate II (FeSO ₄ · 7H ₂ O) and sodium hydrosulfite (Na ₂ S ₂ O ₄ · 2H ₂ O) in a ratio of 10: 1. A 5% aqueous glycerin solution of potassium iodide (KJO ₃ ) is used as an indicator, acidified (1-2%) with sulfuric acid and forms a dark green (bog) compound with ZXR.

Example 3

The method is carried out as in example 1, but the paper is sealed with two white inks based on iron phosphate III (FePO ₄ ) and on the basis of a mixture of iron sulfate II (FeSO ₄ · 7H ₂ O) with sodium hydrosulfite (Na ₂ S ₂ O ₄ · 2H ₂ O). A 5% water-glycerin acidified solution of potassium iodide (KJO ₃ ) is used as an indicator, forming compounds of blue and dark green color in places of printing of the first and second colors of the ink.

Example 4

The method is carried out as in example 1, but the paper is impregnated with potassium nitrite (KNO ₂ ). Printing is done with water- or alcohol-borne white ink, in which 1-2% of potassium iodide (KJ) is previously dissolved. The indicator of authenticity is a water-glyceric acid solution that forms colored compounds of dark brown color at the print sites.

Example 5

The paper is obtained as in example 4, but printing is done with a colorless water or alcohol-borne ink, in which a 1-2% solution of sulfanilic acid sodium salt is pre-dissolved. Indicator: alkaline solution of 5% β-naphthanol, which forms colored compounds of red-orange color at the print sites.

Example 6

The method is carried out as in example 4, but the paper is additionally sealed with a second ink with sulfanilic acid dissolved in it, and a 5% solution of α-naphthylamine in dilute hydrochloric acid is used as an indicator, forming colored compounds of respectively dark brown in the places of printing of the first and second inks and pink.

Example 7

The paper was made according to example 1 by impregnation with yellow blood salt, but in addition to paint based on iron phosphate, a second (masking) light green water or alcohol-based paint based on reactive nickel ferrocyanide pigment (Ni ₂ [Fe (CN) ₆ ]) is additionally introduced into the amount of 10-20%. As an indicator, an alkaline solution of dimethylglyoxime is used, which forms yellow-brown colored compounds at the places of printing of the first ink, and a bright crimson color at the places of printing of the second ink.

As can be seen from the above examples, the proposed method allows to obtain paper with difficult to decipher multilevel chemical protection while reducing the cost of protection due to the introduction of one of the components of SXR with the composition of printing ink.

Claims (6)

1. Security paper, protected from counterfeiting by the introduction of a protective chemical reagent, the presence of which is determined by a colorimetric indicator of authenticity, characterized in that it contains different chemicals in the paper and in the ink applied to the paper, capable of interacting with each other in the presence of an appropriate authenticity indicator with the formation of colored reaction products at the places of contact of paper and paint, while each of the chemicals separately does not interact with this indicator with the image aniem colored compounds. 2. A method of manufacturing a security paper against counterfeiting, comprising introducing into the paper or paper pulp the main chemical reagent, characterized in that at least one additional chemical reagent is introduced into the paint used when applied to paper, while the chemicals used are selected from calculating the interaction of the main and additional reagents with each other in the presence of an appropriate colorimetric indicator of authenticity with the formation of colored reaction products and otsu the interaction of each reagent separately with this indicator of authenticity. 3. The method according to claim 2, characterized in that the chemical reagents are introduced into the paper by surface treatment of the paper together with sizing compositions or by feeding them in the form of aqueous solutions into the paper pulp, followed by precipitation on cellulose fibers by transferring them into an insoluble form. 4. The method according to claim 2, characterized in that the chemical reagents are introduced into a colorless or white paint in the form of aqueous or alcohol solutions or white reactive pigments. 5. The method according to any one of claims 2 to 4, characterized in that the printing on paper is additionally carried out by masking reactive inks, forming colored reaction products when interacting with an authenticity indicator. 6. The method according to any one of claims 2 to 5, characterized in that the application of ink is carried out on printing and / or paper-making equipment.