RU2266355C1 - Counterfeit-protected security paper and method for manufacturing counterfeit-protected security paper - Google Patents

Abstract

FIELD: special-purpose paper types.

SUBSTANCE: method involves treating a part of suspension ingredients, selected from cellulose fibers or powder-like filler, with a color-producing reagent.

EFFECT: enhanced protection effectiveness; reduced reagent consumption.

5 cl

Description

The invention relates to the production of valuable types of paper, banknotes, documents and other types of paper with protection against counterfeiting by introducing chemicals.

A security paper is known consisting of a base paper coated with a mixture of a color-forming dye in a leucoform, a filler (for example, chalk) and a binder (starch, latexes). In this case, color manifestation is carried out with a stamp with a mixture of dark paint and an acidic reagent with the formation of a color halo D around a dark colorful print. The process is due to the chemical interaction of a color-forming dye and an acidic reagent (GB 1507454, 04/12/1978).

Also known is paper protected from counterfeiting and unauthorized production, consisting of base paper and a coating containing metal salt, which changes color when heated (FR 2643661, 08/31/1990).

A known method of marking materials using ink that changes color when treated with bleach. The ink contains two dyes, the coloring ability of one of them deteriorates in the presence of bleach, and the second retains its characteristic color (Patent US 5232494, 1993).

However, these methods do not provide a sufficient degree of protection.

Known methods of protecting documents for special purposes by introducing into the material local security signs.

For example, a protective thread of synthetic thermoplastic polymers is introduced into the material, which consists of 2-3 complex twisted threads, strained and twisted together, while the initial pneumocompound multifilament threads have the same linear density of 20-30 tex, the number of pneumocompounds 20-50 per 1 m and a twist of 420-600 torsions per 1 m, moreover, one of the multifilament yarns is colorless or dyed with dyes visible in daylight, and the remaining yarns are colored with luminescent dyes, while the dye concentration in each yarn is 0.01-1.5 wt.% (RU 2216613, 11.20.2003 g).

A known method of manufacturing securities with a protective thread, according to which pure cotton fibers in the form of peeled cotton raw materials and fluorescent fibers are introduced into the pulp in the pulp manufacturing process. Cotton fibers make up from 10 to 30% of the total mass and form the inner fiber matrix, and the thread included in the paper is tightly connected to the inner fiber matrix (RU 2170788, 07.20.2001).

A known method of introducing labels directly into the fibers and textile threads by dyeing. The label is a rare earth chelate. Colorless filaments in sunlight or artificial light begin to fluoresce under the influence of UV light, and the fluorescence wavelength varies with temperature and is an important distinguishing feature of a particular label (Patent US 5118349, publ. 1992).

The methods described above are complicated and expensive.

Known paper is protected from a fake, containing at least two chemical reagents, each of which is made in such a way that ensures the color reaction of this chemical reagent with an authenticity indicator at a speed that does not match the color reaction rate of each of the other chemical reagents with this authenticity indicator, wherein the color of at least one of the reaction products of each chemical reagent with an authenticity indicator is different from the color of at least one of reaction products of each of the remaining chemicals with this authenticity indicator (RU 2222655, 01/27/2004).

The closest in technical essence and the achieved result is a method of manufacturing paper that is protected from counterfeiting, according to which a water-soluble compound having color-forming properties of a chemical reagent capable of forming reaction products of a certain color when interacting with a color indicator is injected into the paper suspension and the paper web is cast. Moreover, in a preferred embodiment, the color-forming compound is not converted into a water-insoluble form (RU 2229547, 05/27/2004).

The disadvantage of the above methods, including the prototype method, is the high consumption of chemicals, as well as the inability to implement local paper protection.

An object of the present invention is to provide an economical method for manufacturing counterfeit paper, reducing reagent consumption while providing a high degree of paper protection.

The problem is solved by the described method of manufacturing paper, protected from falsification, including the preparation of a suspension of paper pulp, its protective treatment with at least one color-forming reagent to obtain a compound capable of forming reaction products of a certain color when interacting with a color indicator, and the paper web is cast simultaneously with the introduction of a dispersion of components subjected to a protective treatment, in an untreated suspension of paper pulp containing uyusya component part, said maintenance is carried out on predetermined portions of area of the molded paper web.

Preferably, during the casting of the paper web, a 0.3-1.0% dispersion of the components subjected to the protective treatment is introduced.

Preferably, the reagent-treated portion of the pulp components is 1-10 weight% of the total amount of components fed to the paper web.

The method provides for the possibility of processing a color-forming reagent with conversion to a water-insoluble form in several stages using different reagents at each stage.

The problem is also solved by paper, protected from counterfeiting by the introduction of chemical reagents, manufactured by the method described above.

Example 1

A slurry of paper pulp is prepared, which contains long-fiber bleached cellulose, white hydrophilic pigment (talc) and water.

In a separate container, unmilled long-fiber bleached wood pulp in an amount equal to 10 weight% of the pulp components is impregnated with an aqueous solution of oxalic iron (III) K | FeC ₂ O ₄ ) ₃ | at the rate of 1 liter of a 10% solution per 1 kg of fiber, then it is converted into a water-insoluble form by treatment with an aqueous solution of polyhexamethylene guanidine at the rate of 1 liter of a 5% solution per 1 kg of fiber. The fibers subjected to the described processing are dissolved in water and fed into a predetermined area of the cast paper web in the form of a 1% dispersion using a known device for the zonal (in the form of a strip) introduction of protective components installed in the cast zone of a round-the-clock paper machine manufactured by Luzental. The number of processed fibers introduced during the paper tint is selected taking into account the specified width of the protective strip. An indicator of the authenticity of the resulting paper is a 5% aqueous solution of sodium azide (NaN ₃ ). The trace from the felt-tip pen, refueled by the indicator, at the intersection of the strip with reactive fibers turns bright orange, turning yellow-brown for 5 minutes.

Example 2

The paper is prepared, as in example 1: unrefined bleached wood pulp is impregnated in a separate container with a 10% aqueous solution of potassium oxalate iron (III) K | Fe (C ₂ O ₄ ) ₃ | at the rate of 1 liter of solution per 1 kg of fiber, then it is converted into a water-insoluble form by treatment with a 5% aqueous solution of polyhexamethylene guanidine at the rate of 1 liter per 1 kg of fiber. The resulting fibers are washed with water and cleaned of excess moisture in a mesh centrifuge, followed by treatment in a separate container, first with a 1% alkaline solution of thymolphthalein (pH indicator) at the rate of 2 liters of solution per 1 kg of fiber, and then with 1% sulfuric acid solution until neutral. In this case, discoloration of thymolphthalein occurs and its conversion to a water-insoluble form. The fibers obtained as a result of the described treatment are diluted with water to a dispersion concentration of 0.5% and fed to a device for their zonal introduction into paper on a round-the-clock paper machine. The amount of processed fibers introduced at low tide is 5% of the total weight of the paper pulp. An indicator of the authenticity of the obtained paper is a 5% alkaline solution of sodium azide (NaN ₃ ), which forms dark blue compounds with a complex protective reagent with a transition in yellow-brown color for 1-5 minutes. The transition time is determined by the concentration of alkali in the indicator solution.

Example 3

Prepare a pulp for low tide. Part of the bleached cotton pulp intended for paper manufacture is impregnated in a separate container with a 0.5% aqueous solution of sodium dichlorophenolindophenolate (redox indicator) at the rate of 1 liter of solution per 1 kg of fiber, then the fibers are treated with a 1% aqueous solution of ascorbic acid acid until neutral. In this case, sodium dichlorophenolindophenolate is discolored and converted to a water-insoluble form. The resulting reactive fibers are diluted with water to a dispersion concentration of 0.3% and fed to the device for their zonal introduction into paper in an amount of 1% on a round-mesh paper machine.

Authenticity indicator: acidified 10% solution of potassium iodide (KYO ₃ ), forming a red-violet compound with a protective reagent, turning into blue color within 1-5 minutes. The transition time is determined by the concentration in the solution of acid and the presence in the paper of an alkaline filler (chalk).

Example 4

A suspension of cellulose fibers is prepared for paper tinting. In a separate container, talc-pigment, taken in an amount of 10% by weight of the fiber, is impregnated with a 1% aqueous solution of sodium dichlorophenolindophenolate at the rate of 1 liter of solution per 1 kg of pigment, then the pigment is treated with a 1% aqueous solution of ascorbic acid until neutral. The resulting reactive pigment is dispersed in a 5% aqueous solution of sodium carboxymethyl cellulose or another water-soluble polymer (to increase the stability of the dispersion) and, in the form of a 1% dispersion, is fed to a device for zonal introduction into paper on a round-mesh paper machine. Authenticity indicator: acidified 10% solution of potassium iodide (KYO ₃ ), forming a red-violet compound with a protective reagent with a transition in blue for 1-5 minutes.

Example 5

The paper is prepared as in example 4, but the chalk is treated, which is impregnated in a separate container with a 1% aqueous solution of sodium 4-amino-1-naphthalene sulfonate at the rate of 1 liter of solution per 1 kg of pigment, followed by the addition of 1% sulfuric acid solution until neutral. The resulting reactive pigment is dispersed in a 5% aqueous solution of Moviol-40 brand polyvinyl alcohol and, in the form of a 1% dispersion, is fed to a device for zonal introduction into paper on a paper machine. The authenticity of the paper is determined by the bright blue glow of the strip upon UV irradiation of the paper and the disappearance of fluorescence upon contact with the authenticity indicator, which is used as an acidified (pH 3-4) 10% aqueous solution of sulfanilic acid and sodium nitrite in a 1: 1 ratio. At the same time, in the places where the indicator contacts the reactive pigment (with 4-amino-1-natalin sulfonic acid), an orange diazo dye is formed.

Example 6

Prepare a suspension of paper pulp. In a separate container, hydrophilic kaolin, in an amount of 1% by weight of the fibers, is impregnated with a 2% aqueous solution of diphenyl guanidine phosphate at the rate of 1 liter of solution per 1 kg of pigment, followed by the addition of a 1% alkali solution (NaOH or KOH) until a slightly alkaline reaction ( pH ~ 8). The pigment thus treated is dispersed in a 5% aqueous solution of sodium carboxymethyl cellulose and, in the form of a 1% dispersion, is fed to a device for zonal introduction into paper on a paper machine. Indicator of authenticity: 10% aqueous solution of sodium hypochlorite (NaOCl), which forms dark brown compounds with diphenylguanine.

As a result of this invention, the following tasks are solved:

- achieved a high degree of protection and the complexity of the reproduction of the developed technology through the use of water-insoluble reagents with complex structure for decryption;

- simplicity of determining the authenticity of the product by the color of the reaction products of protective reagents with a colorless indicator solution, tucked into the felt-tip pen;

- a significant (tenfold) reduction in the cost of paper with chemical protection in comparison with the currently used method.

The method involves the introduction of color-forming protective reagents into the paper, the action of which is based on various mechanisms - redox, pH, etc. This provides the possibility of a high degree of protection due to the introduction of two or more protective reagents.

Claims (5)

1. A method of manufacturing a paper protected from counterfeiting, including preparing a suspension of paper pulp, its protective treatment with at least one color-forming reagent to obtain a compound capable of forming reaction products of a certain color when interacting with a color indicator, and the ebb of a paper web, characterized in that part of the components of the suspension selected from cellulose fibers or powder filler is subjected to a color-forming reagent treatment, followed by color rendering uyuschego reactant in water-insoluble form, and ebb of the paper web is carried out with the introduction of a dispersion of components subjected to protective treatment in untreated pulp suspension containing the remainder of components, wherein said administration is performed on predetermined portions of area of the molded paper web. 2. The method according to claim 1, characterized in that during the ebb of the paper web, 0.3-1.0% dispersion of the components subjected to the protective treatment is introduced. 3. The method according to claim 1, characterized in that the portion of the pulp components processed by the reagents is 1-10 wt.% Of the total number of components fed to the casting of the paper web. 4. The method according to claim 1, characterized in that the treatment with a color-forming reagent with conversion to a water-insoluble form is carried out in several stages using different reagents at each stage. 5. Paper, protected from falsification by the introduction of chemical reagents, characterized in that it is made by the method described in claims 1-4.