EP0190087B1 - Forge-proof security paper, process for making a paper forge-proof and aqueous or organic composition especially useful in making a paper forge-proof - Google Patents

Description

The invention relates to the field of stationery. It relates to a new tamper-proof security paper comprising an aromatic product, a process for rendering a paper to be tamper-proof and an aqueous or organic composition useful, in particular, for rendering a tamper-proof paper.

State of the art

The so-called "security" papers, which can be used in particular for the production of handwritten payment documents and official documents such as checks, traveller's checks, etc., must be protected against any attempt to falsify the writings or seals carried on papers, using any chemical reagent or modern process, such as an ink eraser. These facer pencils allow to cleanly eliminate the colored inks currently used for handwriting or printing by ink pads.

However, most security papers, currently available on the market, react only insufficiently to attempts to falsify with ink erasing pencils. Often, this causes the appearance of a fluorescent yellow color that is difficult to see with the naked eye and, moreover, can be troublesome for certain uses.

Thus, French Patent No. 2,365,656 describes a security paper comprising a chemical sensitizing composition based on an indicator of acid-basicity, very sensitive to variations in pH. The indicator is chosen, in particular, from the group of phthalein or sulfophthalein. When the pH rises (due to the action of the eraser), the paper develops a color. However, all of the products described are of delicate papermaking use, mainly because of their solubilization conditions, pH of use or reversibility or stability.

French Patent No. 2,399,505 and its certificate of addition 2,402,739 describe a security paper comprising a chemical sensitizing composition based on a salt of oxypyrene tricarboxylic acid, called Pyranine. The action of a facer pencil on such papers develops a fluorescent yellow coloring.

French patents no. 2 406 027, 2 427 426 and its certificate of addition 2 432 576 describe a security paper comprising dinitrophenols which, under the action of an erasing pencil, are colored in non-fluorescent yellow.

French Patent No. 2,410,702 describes a security paper comprising a chemical sensitizing composition composed of Pyranin combined with an optical brightener and various other compounds. The action of an erasing felt on such a paper leads to a fluorescent yellow coloring.

Purpose of the invention

The object of the invention is to provide a compound which, associated with a paper, makes it unforgeable, even with erasers, by instantly developing a color clearly detectable with the naked eye.

General description of the invention

The paper according to the invention is characterized in that it comprises, on its surface and / or in its mass, at least one compound corresponding to the formula:

• - R correspond à l'hydrogène, à un groupe alkyle de C₁ à C₈, substitué ou non, à un groupe amine non substitué, N-substitué ou N,N- substitué, à N0₂, à un halogène,
• - _n égale 0 ou 1.
• L'invention concerne, également, un procédé pour rendre infalsifiable un papier caractérisé en ce qu'on associe à celui-ci au moins un composé de formule 1.

in which the substituents R and / or NO ₂ can be in ortho, meta or para of (CH2) "- CN.

• - R corresponds to hydrogen, to a C ₁ to C ₈ alkyl group, substituted or unsubstituted, to an unsubstituted, N-substituted or N, N-substituted amine group, to NO ₂ , to a halogen,
• - _n equals 0 or 1.
• The invention also relates to a method for making a paper which cannot be forged, characterized in that associates with it at least one compound of formula 1.

The paper can have any fibrous constitution, purely cellulosic or partly synthetic, to which can be added the conventional stationery additives, namely mineral fillers, various resistance agents, binders, resins, shading dyes, neutral bonding products, acid or basic, alumina sulfate for acid bonding or pH adjustment.

Many compounds may be suitable for carrying out the present invention.

Among these, we will prefer those corresponding to the following two substructures:

in which the substituent R can be in ortho, meta or para of CN, with R = H, substituted or unsubstituted alkyl, NH ₂ , NHR ', NR'R "(R' and R" can be various aryl groups, in particular substituted by CN and / or NO ₂ groups or alkyl groups), halogen, NO ₂ .

So, for example - metabenzonitrile

2-amino-5-nitro benzonitrile:

3,5-dinitro benzonitrile:

2-chloro-5-nitro benzonitrile

NN di (2-cyano-4-nitro-phenyl) amine:

in which N0 ₂ can be in ortho, meta or para of CH ₂ CN.

• - l'orthonitrophenyl acetonitrile:
• - le para nitrophenyl acetonitrile:
  
  

So, for example:

• - orthonitrophenyl acetonitrile:
• - para nitrophenyl acetonitrile:
  
  

Furthermore, preferably, the paper will comprise at least 0.0001 g / m ² of the compound and, advantageously, between 0.01 and 0.15 g / m2.

The paper can also include sensitizing reagents, similar to those already used currently in security papers, for example products ensuring a modification of the appearance of the paper by contact of the latter with acids, oxidizing reagents. In known manner, these products are introduced, either in aqueous solution, in which case it is necessary to ensure their retention on the fibers by direct bonding or by means of fixing agents, or in the microdispersed or pigmented precipitated state. .

Thus, the ferric chloride / manganese ferrocyanide couple provides a reaction to attempts at falsification by acids, oxidants and erasers with an acid reaction (of the "corector" type).

There is no compatibility problem between the sensitizers and the structural products (1), provided that these sensitizers are neither basic nor reducing. Indeed, the main property, subject of the patent, of the products (1) being to develop a coloration in the presence of bases or reducers (main components of the ink erasing felts), a product (I) / basic product or reducing association would lead to a colored paper which is inert towards an attempt at falsification by a base, a reducer or an erasing felt.

These papers may also contain, in their mass, in the pigmented state, dispersed, one or more dyes insoluble in water but organo-soluble, so as to preserve the writings or statements made on these papers vis-à-vis attempts at falsification using organic solvents. In addition, these papers can be watermarked or contain various devices intended to ensure recognition, such as fibers, pellets, colored and / or fluorescent particles.

A first method for making a falsifiable paper consists of incorporating the compound of formula (1) during the manufacture of the paper.

A second method consists in depositing on one or both sides of a sheet of paper an aqueous composition comprising a compound of formula (1), as defined above, and a coating binder.

Among the coating binders, mention may be made, by way of indication, of synthetic or natural polymers with compatible hydroxy terminations, such as starch, polyvinyl alcohol and cellulose derivatives.

It has been found that it is particularly advantageous to include in the composition, to improve the solubility and reactivity, a synthetic surfactant.

Many surfactants are known and the purpose of the presentation is not to make an exhaustive list.

• - A: détergents anioniques (à l'exclusion des savons vrais). On peut citer, parmi ceux-ci, les alcoylsulfates, comme le laurylsulfate, les alcoylbenzènesulfonates, les oléfines sulfonées,
• - B: détergents neutres ou non -ioniques, parmi lesquels on peut citer les détergents connus dans le commerce sous les marques "PLURONIC" ou "DISPONIL". Ces composés peuvent être obtenus par condensation de l'oxyde d'éthylène avec un alcool ayant un reste hydrophobe, par exemple les condensats de l'oxyde de polyéthylène et d'alcoylphénols,
• - C: détergents cationiques. Ce groupe de détergents peut être défini comme comprenant des dérivés de composés d'ammonium, de phosphonium et de sulfonium quaternaires aliphatiques dans lesquels les radicaux aliphatiques peuvent être à chaîne droite ou ramifiée et où l'un des substituants alipbatiques contient environ 8 à 18 atomes de carbone.

Briefly, surfactants can be classified into three categories:

• - A: anionic detergents (excluding real soaps). Mention may be made, among these, of alkyl sulfates, such as laurylsulfate, alkylbenzenesulfonates, sulfonated olefins,
• - B: neutral or non-ionic detergents, among which mention may be made of detergents known in the trade under the brands "PLURONIC" or "DISPONIL". These compounds can be obtained by condensation of ethylene oxide with an alcohol having a hydrophobic residue, for example the condensates of polyethylene oxide and of alkylphenols,
• - C: cationic detergents. This group of detergents can be defined as comprising derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds in which the aliphatic radicals can be straight or branched chain and in which one of the alipbatic substituents contains approximately 8 to 18 atoms of carbon.

A more complete description of these agents can be found in numerous documents, including French patents 2,014,675 and 2,062,828.

The category of surfactant selected will depend on the structure of the compound corresponding to formula (I) used. Thus, for the substructure compounds (1), a surfactant from category (B) will advantageously be chosen and, for the substructure compounds (2), a surfactant from group (C) and, among these, the quaternary ammonium compounds.

Optionally, chlorine activators such as bleach can be added to this composition.

• - 0,5 à 50 g de composé de formule (1) seul ou en mélange,
• - 10 à 150 g de liant de couchage (suivant le liant utilisé),
• - 5 à 50 g d'agent tensioactif,
• -1 à 100 g des autres adjuvants (par example des activateurs).

Preferably, the composition comprises in grams per liter of water:

• - 0.5 to 50 g of compound of formula (1) alone or as a mixture,
• - 10 to 150 g of coating binder (depending on the binder used),
• - 5 to 50 g of surfactant,
• -1 to 100 g of other adjuvants (for example activators).

A third method consists in depositing on one or both sides of a sheet of paper a composition comprising a compound of formula (1), an organic solvent and a compatible coating binder. As solvent, there may be mentioned esters, ketones, alcohols, essences or aromatics.

However, this process leads to a paper which does not react to the action of the solvent which was precisely used during this process.

It should be noted that the term composition designates solutions, that is to say the compositions in which the constituents are in the form of solutes but, also, the dispersions partially or not dissolved.

These compositions can be deposited using a coating technique used in stationery (for example size press, roller systems, blade.

A subject of the invention is also the compositions as such.

Example 1

• - 1 g de paranitrophenylacetonitrile
  
• - 10 g de chlorure de dodecyl pyridinium,
• - 100 g d'amidon,
• - 0,5 g d'activateur (eau de Javel)

On a paper support containing by mass reagents (ferric salt and manganese ferrocyanide precipitate) and one or more dispersed organosoluble dyes, these products being intended to give the paper sensitivity to acids and solvents which can be used to falsify the paper, is deposited on the surface, using a conventional papermaking technique (sizing press, roller systems), the coating solution comprising per liter of water:

• - 1 g of paranitrophenylacetonitrile
  
• - 10 g of dodecyl pyridinium chloride,
• - 100 g of starch,
• - 0.5 g of activator (bleach)

The coloring obtained with ink erasers and bases is purple-magenta.

With aging, the colors produced with the bases tend towards green.

The paper thus treated also reacts with bleach, giving a beige-brown color, with acids and acid-erasing products (of the "corector" type), producing blue, the solvents color differently the paper according to their nature.

Example 2

• -10 g d'orthonitrophenyl acetonitrile
  
• - 10 g de chlorure de dodecyl pyridinium,
• - 20 g d'alcool polyvinilique Rhodoviol 30-5 (R) (de RHONE-POULENC).

On a paper support containing by mass reagents (ferric salt and manganese ferrocyanide precipitate) and one or more dispersed organosoluble dyes, these products being intended to give the paper sensitivity to acids and solvents which can be used to falsify the paper, is filed in surface, using a conventional papermaking technique (sizing press, roller systems), the coating solution comprising per liter of water:

• -10 g of orthonitrophenyl acetonitrile
  
• - 10 g of dodecyl pyridinium chloride,
• - 20 g of polyvinyl alcohol Rhodoviol 30-5 (R) (from RHONE-POULENC).

The instant coloring obtained with ink erasing pencils, reducers and bases is pink. Acids and acid reaction products (of the "corector" type) lead to a blue color, bleach to a brown color and the solvents to variable colors depending on the solvent and the dye introduced into the mass.

Example 3

• -4 g de amino-2 nitro-5 benzonitrile (produit SANDOZ)
  
• - 24 g de Disponil SML 120 (R) (produit commercialisé par la Société HENKEL),
• - 20 g d'alcool polyvinylique Rhodoviol 30-5 (R) (de RHONE-POULENC).

On a paper simply containing a dye dispersed in the mass, it is possible to obtain pink-magenta dyes with ink erasing felts, bases and reducers, and variable dyes with solvents (depending on the solvent and the dye used) with a surfacing solution containing per liter:

• -4 g of 2-amino-5-nitro benzonitrile (SANDOZ product)
  
• - 24 g of Disponil SML 120 (R) (product sold by the company HENKEL),
• - 20 g of polyvinyl alcohol Rhodoviol 30-5 (R) (from RHONE-POULENC).

The reaction with acids, bleach and acid reaction erasers (of the "corector" type) can be obtained by addition of products usually known in the coating solution or in the bulk.

Example 4

• - du dinitro-3,5 benzonitrile à une concentration d'au moins 0,5 g par litre,
  
  du chlorure d'hexadecyl pyridinium, par exemple à 12 g par litre,
• - un liant de couchage pouvant être de l'amidon ou des alcools polyvinyliques.

On a paper support, identical to that of Example 1, the coating solution containing:

• - 3,5-dinitro benzonitrile at a concentration of at least 0.5 g per liter,
  
  hexadecyl pyridinium chloride, for example at 12 g per liter,
• - a coating binder which can be starch or polyvinyl alcohols.

Reactions to falsification attempts cause a reddish-pink coloration with reducers, bases and ink erasers, blue with acids and acid-reactive erasers (of the "corector" type), brown with water Bleach and variable depending on the solvents used.

Example 5

• - 5 g de chloro-2 nitro-5 benzonitrile
  
• - 24 g de Disponil SML 120 (R) (produit HENKEL),
• - 20 g d'alcool polyvinylique Rhodoviol 30-5 (R) de RHONE-POULENC.

On a paper support presenting the products already mentioned (ferric salt, manganese ferrocyanide precipitate, organosoluble dye) which can be incorporated into the mass, the coating solution containing:

• - 5 g of 2-chloro-5-nitro benzonitrile
  
• - 24 g of Disponil SML 120 (R) (HENKEL product),
• - 20 g of polyvinyl alcohol Rhodoviol 30-5 (R) from RHONE-POULENC.

The paper thus treated becomes purple-magenta in the presence of bases, reducers or erasable felts, and. as before, in blue with the acids and the acid-erasing products with acid reaction (of the "corector" type), in brown with the bleach and of a variable coloring according to the solvents (according to the dye used).

Example 6

finement divisé, en association avec du chlorure d'hexadecyl pyridinium. Après formation de la feuille, on obtient une réactivité identique à celle décrite dans l'exemple 1 (coloration magenta avec les crayons effaceurs, les bases et les réducteurs, bleue avec les acides et les produits effaceurs à réaction acide (du type "corector") , marron avec l'eau de Javel, variable avec les solvants).During the manufacture of a paper support, are introduced into the mass, in addition to the reagents previously described as a ferric salt, a precipitate of manganese ferrocyanide and one or more dispersed organosoluble dyes, paranitrophenyl acetonitrile:

finely divided, in combination with hexadecyl pyridinium chloride. After formation of the sheet, a reactivity identical to that described in Example 1 is obtained (magenta coloring with erasers, bases and reducers, blue with acids and erasers with acid reaction (of the "corector" type). ), brown with bleach, variable with solvents).

Example 7

• - 1 g de p-nitrophenyl acétonitrile
  
• - 10 g de chlorure de dodecyl pyridinium,
• - 1 000 g d'acétate d'éthyle,
• -50 g d'Ixan SGA (R) (polychlorure de vinylidène commercialisé par SOLVAY).

On the surface of a paper support containing in the mass a ferric salt and manganese ferrocyanide, but no organosoluble dye, the following solution is deposited, by a conventional coating technique (for example engraved roller, roller systems, flexography) :

• - 1 g of p-nitrophenyl acetonitrile
  
• - 10 g of dodecyl pyridinium chloride,
• - 1000 g of ethyl acetate,
• -50 g of Ixan SGA (R) (polyvinylidene chloride marketed by SOLVAY).

Reactions to falsification attempts cause a pink coloration with the reducers, blue with the acids and the acid-erasing products (of the "corector" type), purplish with the bases, brown with bleach. Eraser pencils form violet-magenta traces, stable over time.

Example 8

• - 0,05 g de N-N-di (cyano-2 nitro-4 phenyl) amine
  
• - 24 g de Disponil SML 102 (R) (produit HENKEL),
• -20 g d'alcool polyvinylique Rhodoviol 30-5 (R) (produit RHONE-POULENC).

On a paper support containing in the mass of reagents (ferric salt and precipitate of manganese ferrocyanide) and one or more dispersed organosoluble dyes, the preparation is deposited on the surface, by a conventional papermaking technique (for example size press, roller system) following including per liter of water:

• - 0.05 g of NN-di (2-cyano-4-nitro-phenyl) amine
  
• - 24 g of Disponil SML 102 (R) (HENKEL product),
• -20 g of Rhodoviol 30-5 polyvinyl alcohol (R) (RHONE-POULENC product).

Reactions to falsification attempts cause a pink-magenta coloration with reducers, bases, erasers, blue with acids and acid reaction erasers (of the "corector" type), brown with bleach and variable depending on the solvents used (and the dyes put in the mass).

In all of the preceding examples, the paper is white and not fluorescent after facing.

Claims (15)

1. An unfalsifiable safety paper, characterized in that it contains, on its surface and/or in its bulk, at least one compound corresponding to the formula:

in which

R corresponds to hydrogen, a substituted or unsubstituted C₁ to C₈ alkyl group, an unsubstituted, N-substituted or N,N-substituted amine group, N0₂ or a halogen, and

- n equals 0 or 1.

2. The safety paper according to claim 1, characterized in that the compound corresponding to the formula (I) has the following structure:

in which R corresponds to H, substituted or unsubstituted alkyl, NH₂, NHR', NR'R" (it being possible for R' and R" to be various aryl groups, especially those substituted by CN and/or N0₂ groups, or alkyl groups), halogen or N0₂.

3. The safety paper according to claim 1, characterized in that the compound corresponding to the formula (I) has the following structure:

4. The safety paper according to claim 2, characterized in that the compound is selected from the group comprising the following compounds:

- metabenzonitrile (sic)

- 2-amino-5-nitrobenzonitrile

- 3,5-dinitrobenzonitrile

- 2-chloro-5-nitrobenzonitrile

- N,N-di(2-cyano-4-nitrophenyl)amine

5. The safety paper according to claim 3, characterized in that the compound is selected from the group comprising the following compounds:

- orthonitrophenylacetonitrile

- paranitrophenylacetonitrile

6. The safety paper according to claim 1, characterized in that the paper contains at least 0.0001 g/m² of the compound of the formula (I).

7. A process for rendering a paper unfalsifiable, characterized in that it comprises associating therewith at least one compound defined in one of claims 1 to 5.

8. The process according to claim 7, characterized in that the compound is associated with the paper when the latter is being manufactured.

9. The process according to claim 7, characterized in that an aqueous composition containing a compound of the formula (I) as defined in claims 1 to 5, and a coating binder, is deposited onto one or both surfaces of a sheet of paper.

10. The process according to claim 9, characterized in that the composition also contains a surfactant.

11. The process according to claim 9 or 10, characterized in that the composition contains (in grams/liter):

-0.5 to 50 g of compound of the formula (I), by itself or in a mixture,

- 10 to 150 g of coating binder,

- 5 to 50 g of surfactant and

- 1 to 100 g of other adjuvants (for example activators).

12. The process according to claim 11, characterized in that the compound corresponds to the formula defined in claim 2 and the surfactant is neutral.

13. The process according to claim 11, characterized in that the compound corresponds to the formula defined in claim 3 and the surfactant is cationic.

14. The process according to claim 7, characterized in that an organic composition containing a compound of the formula (I) and a compatible coating binder is deposited onto one or both sides of a sheet of paper.

15. An aqueous or organic composition as defined in one of claims 9, 10, 11, 12,13 and 14, which can be used in particular to render a safety paper unfalsifiable.