DD300786A7 - Counterfeit-proof paper - Google Patents

Abstract

The invention relates to an anti-counterfeit paper containing at least one reducing agent-responsive reagent. It has set itself the task to produce a special paper, which limits the possibilities of attempted or made counterfeiting as far as possible or makes impossible. The object was inventively achieved in that the special paper as a reactive system contains tetrazolium compounds of the general formula in which the radicals R ind 1, R ind 2 and R ind 3 aryl and / or hetaryl, optionally R ind 1 also alkyl, and X is a may be inorganic or organic acid radicals, wherein the organic acid radical may be an acid-modified polymer. formula

Description

Field of application of the invention

The invention relates to a tamper-proof paper, in particular one containing at least one against reducing agent responsive reagent.

Characteristic of the known technical solutions

High-quality special and security papers should be such that their counterfeiting and / or falsification and their misuse on the one hand as difficult as possible to accomplish, on the other hand as easy and quick to recognize.

Numerous technical solutions have already been provided for protection against alteration, counterfeiting and misuse of fonts, signatures and stamps and / or special information on handwritten and / or typewritten or printed special papers and official documents in payment transactions, travel and security documents.

These are considered significant only in their specific type, but have also in the form of their use or their A ¹ .wandung numerous disadvantages.

For example, the significantly functional protection of special papers by mottling, the incorporation of genuine and / or spurious watermarks, the sensitization to oxidants and to alkalis and / or acids, by specific security printing, the sensitization to solvents by incorporation of fluorescent or luminescent substances are known

However, the use and use of such reagents or materials also require the use of special technologies. Lack of all these previously known special papers is that the information-bearing surface or the information itself can be counterfeited and / or falsified or imitated even when intervening with reductive reagents and that the special paper can continue to be abused.

Object of the invention

The aim of the invention is to produce a tamper-proof paper which contains at least one reagent which is responsive to reducing agent and is thus sensitized to attempts to modify or falsify fonts and / or information using reducing agents.

Explanation of the essence of the invention The invention has set itself the task eich produce a special paper, which the possibilities after attempted or

counterfeiting as far as possible or makes it impossible.

The object could be solved according to the invention, because it was surprisingly found that the only

described as applicable only for biological and biochemical processes ¹ enen and used

Tetrazolium salts are also suitable for sensitizing special papers. By own experiments could be proven that the tetrazolium salts with solutions and dispersions of in the Paper industry used special means for paper impregnation and / or surface sizing compatible

are and do not undergo color reactions.

It has also been found that these salts with previously used sensitivity to oxidizing agents

compatible and therefore can be used in combination.

According to the invention further, that by special combinations with coordinated mixing ratio with

natural and / or synthetic polymers in the pH range from 4.5 to 6.5, the tetrazolium salts in aqueous dispersion

Be used as significant protective coatings or protective colloids of these salts against oxidation by Serve atmospheric oxygen. In this case, the addition of tetrazolium salts in the order of 0.005% to 0.05%, based on atro pulp,

and / or 0.001% to 0.06%, based on impregnating or surface-sizing substance.

To protect the reversal of the process, which is only possible under very specific conditions, this will be Reaction system with substances sensitized to oxidizing agents in the order of 0.2% to 1.0%,

based on atro pulp, or 5% to 25%, based on atro substance on impregnating or Oberflächenleimbad, but which are compatible with the tetrazolium salts and do not react with these or enter into any disturbing or visible reaction.

Thus, a reversal of this reaction by visualization is excluded. Furthermore, it is largely excluded by the significant mixture with natural and synthetic polymers,

that the reduction of the tetrazolium salts goes beyond the formazan stage and the N = N double bond of a hydrogenating

Azo cleavage falls victim. Thus, those rare in organic chemistry and for use as sensitizers

For the protection of specialty papers, the property of the tetrazolium salts, preferably of the triphenyltetrazolium chloride, that the oxidation state is colorless and the reduced form, the so-called "Leuko step", fully utilized at the

Irradiating with light under specific conditions forms a fluorescent photoderivative. Upon exposure of Triphenylformazan with the addition of absolute alcohol with UV light, this decolorizes almost under Formation of a sky blue fluorescent cation, which can also be used for depth testing. A significant advantage of the use of tetrazolium salts is that the reductive splitting of the tetrazole ring to the Formazans are light and fast and thus very sensitive. With reducing agents takes place among the mildest Conditions ring splitting takes place. To further increase the light stability, the reactive system can be significantly bound to organic polymers. In this case, preferably acid-modified polymers are used, whereby the use of these stabilizing substances

can be done both in the mass and in the impregnating and / or Oberflächenleimprozeß.

Another possibility for light stabilization can be realized by adding known light stabilizers, from

which, for example, up to about 1% can be used for the reaction system, the combination of a

Do not interfere with sensitization to oxidizing agents and also with respect to other species of the special papers Aggregates show no disturbing reactions. Ausführungsbelspiele The invention will now be explained in more detail with reference to 4 examples. example 1 A special paper with a basis weight of 90 g / m ² is passed through after passing through the pre-dryer section of a paper machine

a Oberflächenleimbad out, consisting of a coordinated mixing ratio of z. B.

62.5% of amyl, 12.5% of a copolymer based on acrylic ester free of plasticizers and solvents, 3% hydrochloric acid for pH adjustment to pH 4.5 to 6.5, to which 0.005% Triphenyltetrazoliumchlorid are added and that for protection the reaction system against chemical shaving with oxidizing agent 21.995% reaction substance, based on atro solids Gehdlt be added.

The paper sized with this surface finish runs through the after-dryer section of the paper machine. This paper will

provided with special information through printing.

Attempted chemical etching with reducing or oxidizing agents will remain at the sites of attempted intervention

clearly visible stains that make a counterfeiting and / or adulteration attempt significantly evident and preclude further misuse of this special paper.

Example 2 Acid-polymerized polyacrylonitrile containing 2% triphenyltetrazolium salt bound as a white powder in a 0.7% added to the pulp. The paper glued with this surface glue passes through another impregnating bath, consisting of a 0.5%

aqueous solution of a light stabilizer.

The further processing and the sensitization detection run according to embodiment 1. Example 3 A special paper with a surface mass of 80g / m ² is made after sheet formation and passage of Vortrockonpartio

passed through a Oberflächenleimbad consisting of 52.5% of amyl, 10.2% copolymer based on acrylic acid ester, 2.7% hydrochloric acid for pH adjustment to 4.5-6.5,16.8% sensitizer to oxidizing agent , 1% light stabilizer, 16.8% acid modified polyacrylonitrile powder loaded with 2% triphenyltetrazolium chloride.

The paper sized with this surface size passes through the after-dryer section of the paper machine and becomes roll

wound. The Par is printed as in Example 1 and is protected against counterfeiting and / or falsification.

Example 4

A special paper having a basis weight of 100 g / m ² is subjected to surface sizing analogously to working examples 1 and 3. The surface size consists of solids 55.5% of amylum, 20% copolymer, based on acrylic acid ester, 3% hydrochloric acid, 20.4% sensitizer to oxidation, 0.025% 2,5-diphenyl-3,4,5-dimethyl-thiazolyl (2) tetrazolium bromide, 0.005% cobalt nitrate and 1% light stabilizer. While in the embodiments 1-3 upon exposure to reducing agents forms a deep red to pale red color by formation of stable TriphenylformazoM depending on the amount used, occurs in reduction according to embodiment 4, a blue-black coloration by formation of a cobalt-formazan complex.

Claims (4)

1. Anti-counterfeit paper which has at least one responsive to reducing agent reagent, characterized in that it is used as a reactive tetrazolium compounds of the general formula NR _n in which the radicals R ₁ , R ₂ and R _{3 are} aryl and / or hetaryl radicals, where appropriate R _{1 is} also alkyl, and X can be an inorganic or organic acid radical, where the organic acid radical can be an acid-modified polymer. 2. Anti-counterfeit paper according to item 1, characterized in that the tetrazolium salts are used in combination with natural and / or synthetic polymers in the pH range of 4.5 to 6.5 in aqueous dispersion, wherein the addition of the tetrazolium salts in an order of magnitude from 0.005% to 0.05%, based on atro pulp, and / or 0.001% to 0.06%, based on atro impregnating or Oberflächenleimsubstanz takes place. 3. Anti-counterfeit paper according to item 1 and 2, characterized in that the reaction system to protect the inversion of the process sensitized with oxidizing agents in the order of 0.2% to 1.0%, based on atro pulp, or 5% up to 25%, based on the impregnation or superficial surface adhesive, which are compatible with the tetrazolium salts and do not react with them. 4. Anti-counterfeit paper according to item 1 to 3, characterized in that it contains light stabilizers, preferably up to 1%, based on the reactive system.