RO126417B1 - Security paper and process for preparing the same - Google Patents

Abstract

The invention relates to a security paper for valuable documents and to a process for preparing the same. According to the invention, the paper exhibits high protection degree due to a system of marking elements consisting of a dark-red fibre visible at day light, a fibre of green fluorescence in UV, a fibre with blue fluorescence in UV, a yellow fluorescent pigment visible in UV and 3 chemical compounds with colour reaction upon attack of the paper with chemical substances. The process claimed by the invention consists in forming a mixture consisting of 30...70% resinous trees cellulose sulphate and 70...30% deciduous trees cellulose sulphate, at a grinding degree of 55°SR, to which there are added 9% Ca carbonate, 0.003% fluorescent pigment, 0.024 % dark-red fibres, 0.020% green fluorescence fibres, 0.14% chemical compound for the colour reaction upon solvent attack of paper, 1.5% sizing agent, 0.5% retention agent, the paper pulp being then passed on the watermarking roll, sized in the sizing press with a 6% starch solution wherein there are dosed 0.5% compound for the colour reaction upon the base or acid attack of the paper and 1.5% compound for the reaction upon the chlorine attack, the resulting paper tape being finally dried.

Description

The present invention relates to a secure paper, intended for printing valuable documents, and to a process for obtaining it.

Paper and paper products are part of the group of materials that are widely used in society and have a significant role in all fields of activity. The special importance of this product is explained by the fact that the paper represents the material support for the recording, storage and transmission of information of economic and / or social interest. On the other hand, paper and cardboard are the most used and recommended materials for making packaging and have many specific applications for technical and sanitary products.

The group of technical and special papers represents only about 3% of the world production of paper and cardboard, but their value is impressive, especially in the case of securities. Due to their economic, social and personal role, particularly important, papers or documents are subject to a permanent risk of forgery and counterfeiting. Therefore, valuable papers or documents share a defining characteristic, namely - the concept of security. The careful elaboration of these must provide the documents with a sufficient guarantee of authenticity, in order to be able to represent the value or the right attributed to them by the issuing body.

Apart from very rare exceptions, the value document is made by printing a support paper, each of which gives the document, in varying proportions, the value attributes that guarantee the authenticity and discourage the forgery. There are situations when the value can be attributed only to paper or printing, thus obtaining documents with a sufficient guarantee for particular purposes or applications. Another document can be produced using a type of paper of value, with the necessary characteristics of the guarantee, being printed only with the attention directed to the functional aspects. On the other hand, there is also the option of obtaining a document on plain paper, but using a special printing to avoid the possibility of imitation. However, it is obvious that the best documents of value, with the highest guarantee, can be obtained by combining the perfection of the paper with that of the printing process.

The security elements, which are the basis for the realization of the security concept of the value document, can be classified, according to the way their perception / detection is realized, in:

- security elements perceived / detected through the senses, elements called HR (human readable-readable). The HR security elements are accessible to the general public and in the case of banknotes the information of the public is made when a new issue is put into circulation. With the help of the senses (visually and tactile) it is possible to detect the presence or absence of security elements by which we distinguish and separate authentic banknotes from fake ones. Counterfeiters (artisanal and low quality counterfeiting) generally mimic the security elements known and perceived by the general public;

- security elements detectable with the help of special devices, elements called MR (machine readable - machine readable). MR security elements, essential for verifying the authenticity of the document, are detected by specialized equipment, with 100% accuracy. With these devices, documents (banknotes) can be sorted at high speed in authentic and fake documents. MR security features are not disclosed to the public. The equipment needed to detect forgeries does not prevent counterfeiting, but only detects and separates the false documents from the authentic ones;

- security elements detectable in "laboratory. These elements can be highlighted only after conducting laboratory tests, such as microscopic analysis to highlight the morphology of the fibers in the paper composition or those that relate to the treatment of the paper with various reactants to check the presence of some compounds, specially introduced in the paper composition, which give a specific color reaction.

RO 126417 Β1

The typographers, which included in their field of activity and the production of documents, classify 1 the security elements into elements of type OUVERT (open), COUVERT (hidden) and elements of type FORENSIC (special). An integrated document security system 3 is achieved by using secure papers, graphics elements, special inks, holograms and variable-data personalization elements. 5

Among the most important security elements integrated into the paper we mention:

The composition of the paper. The usual papers are composed of cellulose fibers, in most cases 7, from wood, after the process of wood disassembly, the sorting and bleaching of the resulting fibers. By using a certain percentage of cellulose fiber 9 of another origin (cotton, jute, hemp, flax, reed, bamboo straw, etc.) or synthetic fibers it is possible to ensure the particularization of a certain assortment of paper (each of these 11 fibers has a morphological construction. specific, easy to highlight based on microscopic analyzes). 13

Watermark - it is undoubtedly the element with the safest features for securing paper, based on which one can easily distinguish a document originating from a fake one. Also, the watermark is the security element that can be checked by anyone by simply viewing, in daylight transparency, the drawing reproduced 17 in the sheet of paper. The printing of the drawing is done in the wet strip of the paper, during the forming process. The drawing can be done in several variants: closed tones, 19 open tones, combination of open tones and closed tones or more complex in an alternation of open, closed tones and halftone (portrait watermark). 21

Fluorescent pigments. In the composition of the paper, "fluorescent pigments" type dyes, which have the property of converting ultraviolet light into yellow radiation, can be introduced. 23 Fluorescent pigments are organic, inorganic in nature or are organometallic compounds.

Fibers marked. The use of colored, natural or synthetic fibers represents another 25 methods of securing paper documents. These are embedded in the paper pulp, at different concentrations, their density in the paper sheet being established by the manufacturer of the paper, arbitrarily or at agreement with the paper user, depending on its destination, in the mass of the paper, the marked fibers have , usually a chaotic setting (can also be placed under 29 visible tape on a single surface of the paper or on both sides). The length of the fibers can also be very different, lately fibers with lengths of 31

6 ... 8 mm and with lower densities in the sheet of paper.

Chemical compounds with color reaction. Damage to documents 33 can be done mechanically by shaving (erasers using gum obtained from various materials with specific hardnesses, blades, etc.) or by chemical means, using a wide range of 35 chemicals that could be grouped in: bleaching agents - chlorine compounds, alkaline solutions (bases), acid solutions (acids) and solvents. In order to verify the authenticity of 37 documents and to protect them against attempts to delete, by chemical means, some characters of the print, certain substances known 39 under the name of "tals" products can be dosed in paper paste. When the paper comes into direct contact with one or more attack substances, substances which, depending on their nature, belong to one of the 41 groups mentioned, these reactants cause the colorants of the paper to change their color and implicitly the color of the paper. 43

Safety wires. Some securities, such as banknotes, checks, shares, some identity documents, are protected against forgery by the insertion of 45 security threads or strips. They can be made in a wide range of sizes (yarns or strips with a size of 0.4 ... 10 mm), are metallic or plastic coated with metal, yellowed or colored with different pigments. Moreover, there are wires with magnetic, microtext or thermochrome properties. in paper, they are embedded in whole or only in 49 windows and can be highlighted in transparency (in light incidence they are invisible.

RO 126417 Β1

Thus, a special bank note paper (RO 110352 B1), made from cotton fibers, cellulose sulphate and calcium carbonate, is known, which contains security elements made of three-color fluorescent fibers, added to the forming paste. of paper.

Also known is a paper for special records (EP 1204795 B1) which contains a combination of security elements comprising color reaction compounds upon attack with organic solvents or acids, colored cellulose fibers and treated with light blue coloring agents. UV, a watermark embedded in or printed on the paper and a color reaction layer, respectively, when applying a pressure

Also known is a security document (EP 0185396 B1), which contains a security wire identifiable by direct illumination, the wire having at least two zones with different properties, arranged adjacent to the plane of the document, along the entire length of the wire, so that the arrangement their geometry can be identified without destroying the document.

The disadvantages of these secured papers are that they do not provide an optimal ratio between the manufacturing cost and the quality of the obtained paper.

The technical problem solved by the invention consists in the production of a secure paper, provided with a system of security elements, whose cumulative protection "arguments" provide a lower risk to the document in the face of multiple possibilities of forgery and counterfeiting, and which it can be achieved by a simple and inexpensive process, without the need for special machines.

The secured paper according to the invention removes the disadvantages of the known solutions and solves the mentioned technical problem, in that it consists of 30 ... 70% cellulose sulphate bleached in resins and 70 ... 30% cellulose sulphate bleached in hardwoods, in which it was added 9%, by weight percent, of cellulose material, calcium carbonate, as a filler, and safeguards comprising a fluorescent pigment, yellowish to UV, fibers marked with reddish-gray fibers, visible in daylight, and fluorescent fibers, in two colors, detectable only in UV light, and three chemical compounds with color reaction to the attack of the paper with acidic or basic substances, chlorine and organic solvents.

The process of making the paper consists in the fact that, with a mixture of cellulose bleached sulphate, resinous 30 ... 70% and bleached cellulose sulphate, of hardwood 70 ... 30%, ground in two steps to a final degree grinding of 55 ° SR, and 9% calcium carbonate powder, as filling material, add, to the total fibrous material and filling material, 0.03% fluorescent pigment, 0.025% red-gray fibers, 0.020% green fluorescent fibers in UV, 0.020% white fluorescent fibers, blue in UV, 0.14% chemical component for the color reaction to the attack of solvent documents, 1.5% gluing agent, 0.5% retaining agent after which, the formed paste is deposited on the sieve forming the paper machine, forming a bath that passes over a filigree watering roller and some drying rollers, and finally, is treated in the gluing press with a solution of starch having a concentration of 6%, in car e 0.5% chemical components were used for the color reaction to the attack of documents with acidic or basic substances and 1.5% chemical components for the color reaction to the attack of the documents with chlorine-based substances.

Ensuring a high degree of protection of documents against counterfeiting and counterfeiting attempts means that the supporting paper should contain as many security elements as possible. Therefore, unlike other patents, when making the paper to which the present invention refers, a system of security elements is used whose cumulative protection "arguments" provide the document with a lower risk in the face of multiple possibilities of forgery and counterfeiting. This system consists of the following security elements:

- watermark;

RO 126417 Β1

- marked fibers, respectively: 1

- a reddish-gray fiber, visible in daylight;

- a fluorescent fiber visible only in the field of UV radiation - green, 3

- a fluorescent fiber visible only in the field of UV radiation - blue.

- a fluorescent pigment visible only in UV radiation - yellow, 5

- chemical compounds with color reaction to the attack of documents with:

- chemicals based on chlorine bleaching agents / reaction color-dark brown 7;

- solutions of alkaline substances (bases) / reaction-green to blue color, 9

- solutions of acidic substances (bases) / reaction-pink color;

- Solvents / reaction-blue color.11

According to an embodiment of the invention, the recipe and the manufacturing phases of the paper are as follows: 13

The fibrous recipe is composed of two types of bleached cellulose sulphate, to which was added a filler material and gluing agents - retention, as follows: 15

- bleached cellulose sulphate, from softwood: 30 + 70%;

- the degree of milling of cellulose from resin, in the first milling step - 42 ° SR; 17

- bleached cellulose sulphate, from deciduous: 70 30%;

- the degree of grinding of the cellulose mixture (grinding step II) - 55 ° SR; 19

- the ratio of freshly prepared cellulose paste to the tip returned from the paper machine: 21

- celluloses from the hydrapulper circuit: 90%;

- trowel returned from the paper machine: 10% (with the same fibrous composition). 2. 3

- the final degree of grinding of the fibrous material: 54 ° SR;

- filling material - calcium carbonate: 9% (compared to fibrous material), 25

- gluing agent (gluing in neutral / weak alkaline environment): 1.5% (compared to fibrous material + filling material); 27

- fluorescent pigment: 0.03% (compared to the fibrous material + the filling material);

- reddish-gray fibers, visible in daylight: 0.025% (compared to fibrous material 29 + filling material);

- fluorescent fibers, visible only in the field of UV radiation - green color: 0,020% 31 (compared to cellulose material + filling material);

- fluorescent fibers, visible only in the field of UV radiation - blue: 33

0.020% (compared to cellulose material + filling material);

- chemical component for color reaction to attack of solvent documents: 35

0.14% (compared to cellulose material + filling material);

- retaining agent: 0,5% (compared to cellulose material + filling material), 37

- watermark construction - with the watermark roller mounted on the top of the paper forming screen;

- surface treatment of paper in gluing press with an aqueous solution of oxidized starch, 6% solution concentration, adding: 41

- chemical component for the color reaction to the attack of documents with 0,5% chlorine substances (compared to the starch solution), 43

- chemical component for color reaction to attack of documents with acidic or basic substances 1,5% (compared to starch solution); Softwood pulp (at 30 ° SR45

- breaking length = 9.2 km, at 50 ° SR - breaking length = 9.7 km, white - 86%) and woody cellulose ((at 30 ° SR - breaking length = 8, 0 km, at 50 ° SR -47 breaking length = 9.2 km, white - 86%) are crumbled and hydrated, in batches,

EN 126417 Β1 in a hydrapulper. Dispersion consistency averages 4.0% (range of variation:

3.7 ... 4.6%) and it is corrected at the end of the process of loading the hydrapulper with cellulose, by filling with water up to the marked level mark. The break-up time is 20 ... 30 min, for cellulose from hardwood, and 35 ... 45 min, for cellulose from softwood. After the dismantling process is completed, the celluloses are stored in separate tanks, where their hydration, started in the hydrapulp, is continued during the storage period in the storage tanks.

In the manufacturing recipe, other types of cellulose can be used, their nature and quality being determined according to the document to be made (cotton cellulose).

The celluloses used in the manufacturing recipe are ground in a continuous grinding plant following the following technological variant:

- step I - separate milling of cellulose from resin using as a double-disc refining mill;

- step II - grinding the cellulose mixture, according to the manufacturing fiber recipe, also in double disk refineries, until the final grinding degree is reached.

After grinding, the cellulose paste is prepared for dilution and adding the following additives:

- the paper filling (filling) material - calcium carbonate powder (average particle diameter - d ₅₀ = 2.5 µm, 95% white);

- fluorescent pigment (organic in nature - fine and homogeneous dispersion of pigments with properties of transforming ultraviolet light into yellow radiation);

- the agent for gluing the paper in a neutral medium (alkyl dimercetene emulsion);

- fibers of red-gray color, visible in daylight (natural fibers of viscose, heading - 3.3 dtex, length of thread: 3.0 mm);

- fluorescent fibers, visible only in the field of UV-green radiation (natural fibers of viscose, heading: 5.0 dtex, thread length: 3.0 mm;

- fluorescent fibers, visible only in the field of UV-blue radiation (natural fibers of viscose, heading 6.7 dtex, thread length: 4.0 mm.

For the papers intended for the execution of documents that must have a high durability, the use of the filling material is abandoned.

Next, the mixture is made between the freshly prepared paper paste and the resulting paper machine pitch (wet arm and dry arm). After adjusting the consistency, this paste is pumped into the paper machine tanks.

The paper pulp is purified in an installation consisting of:

- centering - three sorting steps;

- centriscreaner - one step.

The acceptance from the first sorting step is sent, through the centriscreaner sorter to the paper machine launch box. In the aspiration of the material feed pump, of the launching box, it is dosed:

- the retaining agent of the filler and the fine fibrous material (aqueous polyamide-polyamine-epichlorohydrin resin solution);

- the chemical component for the color reaction to the attack of the documents with organic solvents (anthraquinone dye in aqueous dispersion);

From the launch box, the paste of paper, in the form of a jet, reaches the sieve forming the paper machine. With the launch of the paste stream over the entire width of the forming site (launch consistency = 0.3%), the process of dehydration of the paper strip begins, a process favored by the presence, on the table, of the following dehydration elements:

- training box;

- roller coasters;

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- hydrophilic baffles; 1

- baby boxes;

- the baby box, mounted inside the Gautsch roll.3 in the area of the baby boxes, is located the watermark roll of the paper (the watermark drawing has the title of protection). 5

After the formation sieve, the dehydration process is continued in the wet press area, consisting of: 7

- baby press I with two steps;

- Sale-Nip type II press; 9

- III offset socket.

The dryness of the paper strip, at the output of press III, can reach, from case to case, 11 to 38 ... 40%. The dehydration of the paper tape is completed in the drying part of the paper machine, consisting of 14 paper dryers, placed on two rows. The drying cylinders 13 are organized in drying groups, their heating being done with saturated steam at the pressure of 2.4 bar. After the slalom runs through the dryers of the first two dryer groups, the paper tape enters the gluing press or surface treatment press. The paper surface treatment solution contains: 17

- oxidized corn starch (white powder brought into solution after boiling), in which it is added, in the following order: 19

- the chemical component for the color reaction to the attack of documents with acidic or basic substances (xanthan derivative), 21

- the chemical component for the color reaction to the attack of the documents with chlorine-based substances (diphenylguanidine derivative in aqueous solution) .23

After the gluing press, the paper strip enters the last drying group-group III consisting of 6 paper dryers. The temperature at the surface of the drying cylinders is 25, depending on the weight and speed of the paper machine, in the form of a diagram (t = 70 + 115 ° C) .27

For compacting, calibrating and increasing smoothness, the paper strip is then passed through a calender and finally, it reaches the paper wrapping.29

The paper reels from the wrapper are transported by the rolling bridge on a waiting stand or directly to the paper reel where the operations of trimming, sorting 31 primary, longitudinally cutting the paper strip into smaller widths and wrapping the tape are carried out. on cardboard tubes (formation of rolls / coils). 33

The security elements, contained in the paper which is the subject of the present invention, can be detected by the following three methods, respectively: 35

Inspection of paper with the naked eye, in daylight (visible radiation field).

The watermark, respectively, its drawing can be easily found by simply looking at the paper in 37 transparency. Also, the red-grain-marked fibers can be detected by looking at the paper with the naked eye, regardless of the angle of incidence of light in the visible field (39, both the presence of the fibers in the sheet of paper and their color).

Inspection of paper exposed to ultraviolet (UV) radiation. For highlighting the 41 fluorescent pigment and the fluorescent-labeled fibers, a special lamp is used (fig. 1, UV lamp, Betrachter - Lamag) which provides UV radiation, the wavelength of 43 being 366 nm. In these radiations, the eye perceives on paper scattered dots of yellow (pigment particles in the paper composition) and filaments of green color 45 and blue (fluorescent fibers of green and white also introduced in the composition of the paper). 47

RO 126417 Β1

Laboratory or special markers testing of paper for color reactions. As test reagents, the following are used:

- for the chemical component with the color reaction to the attack of the documents with chlorine substances - sodium hypochlorite solution. The spot or stain that appears on the paper, in the area where this substance intervened, must be dark brown in color;

- for the chemical component with the color reaction to the attack of documents with acidic or basic substances:

a) acids - sulfuric acid (c = 5%), the spot color should be pink;

b) basic - sodium carbonate (c = 5%), the spot color should be green to 11 blue;

- for the chemical component with the color reaction to the attack of the solvent documents

- trichlorethylene, acetone, isopropanol. The spot must be blue.

Claims (6)

claims 1. Secured paper for valuable documents, based on bleached cellulose, 3 comprising colored fibers and secure fluorescent fibers, characterized in that it consists of 30 ... 70% bleached cellulose sulphate and 70 ... 30% cellulose deciduous bleached sulfate 5, to which was added 9%, by weight percent, to cellulose material, calcium carbonate, as a filler, and safeguards comprising 7 fluorescent, yellowish to UV, pigmented fibers containing fibers red-grain color, visible in daylight, and fluorescent fibers, in two colors, detectable only in 9 UV light, and three chemical compounds with color reaction to the attack of the paper with acidic or basic substances, chlorine and organic solvents. 11 2. Secured paper, according to claim 1, characterized in that the reddish-colored, securing fibers, visible in daylight, are viscose fibers with a heading 13 of 3.3 dtex and a length of about 3.0 mm. Secured paper according to claim 1, characterized in that the fluorescent fibers are green and blue in UV light. Secured paper according to claims 1 and 3, characterized in that the 17 green fluorescent UV fibers are viscose fibers with a title of 5.0 dtex and a length of about 3.0 mm. 19 5. Secured paper according to Claims 1 and 3, characterized in that the UV-fluorescent blue security fibers are viscose fibers with a heading 21 of 6.7 dtex and a length of about 4.0 mm. 6. Process for obtaining the secured paper of claims 1 ... 5, characterized in that, in a mixture of cellulose sulphate bleached from resins 30 ... 70% and bleached cellulose sulphate from hardwoods 70 ... 30% , ground in two steps to a final degree of 25 milling of 55 ° SR, and 9% calcium carbonate powder, as filling material, with 0.03% pigment added to the total fibrous material and filling material fluorescent, 0.025% fibers 27 red-green, 0.020% fluorescent fibers green in UV, 0.020% fluorescent fibers white, blue in UV, 0.14% chemical component for the reaction of 29 colors to attack documents with solvents , 1.5% gluing agent, 0.5% retaining agent, after which the formed paste is deposited on the paper machine forming sieve, forming a band 31 which passes over a watermarking roller and some drying rollers, and finally, it is treated in the gluing press e with a starch solution having a concentration of 6%, in which 33 0,5% chemical components were used for the color reaction to the attack of documents with acidic or basic substances and 1,5% chemical components for the color reaction to the attack 35 documents with chlorine-based substances.