GB2240511A - Security printing or writing medium - Google Patents
Security printing or writing medium Download PDFInfo
- Publication number
- GB2240511A GB2240511A GB9102451A GB9102451A GB2240511A GB 2240511 A GB2240511 A GB 2240511A GB 9102451 A GB9102451 A GB 9102451A GB 9102451 A GB9102451 A GB 9102451A GB 2240511 A GB2240511 A GB 2240511A
- Authority
- GB
- United Kingdom
- Prior art keywords
- medium
- cobalt
- salt
- medium according
- paper
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 150000003839 salts Chemical class 0.000 claims abstract description 26
- 150000001868 cobalt Chemical class 0.000 claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 230000003647 oxidation Effects 0.000 claims abstract description 10
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 10
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 claims abstract description 9
- 239000004289 sodium hydrogen sulphite Substances 0.000 claims abstract description 9
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 claims abstract description 9
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 claims description 12
- 238000012505 colouration Methods 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 239000011248 coating agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 11
- 239000000126 substance Substances 0.000 claims description 7
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical group [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 6
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 claims description 5
- 229910001981 cobalt nitrate Inorganic materials 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 4
- 229940011182 cobalt acetate Drugs 0.000 claims description 4
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 claims description 4
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 claims description 4
- FJDJVBXSSLDNJB-LNTINUHCSA-N cobalt;(z)-4-hydroxypent-3-en-2-one Chemical compound [Co].C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O FJDJVBXSSLDNJB-LNTINUHCSA-N 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 3
- 239000011780 sodium chloride Substances 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 abstract description 2
- 229910021653 sulphate ion Inorganic materials 0.000 abstract description 2
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 abstract 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 abstract 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract 1
- 229910002651 NO3 Inorganic materials 0.000 abstract 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 abstract 1
- 239000000976 ink Substances 0.000 description 6
- 238000004513 sizing Methods 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000007844 bleaching agent Substances 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- -1 transition metal salt Chemical class 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- 208000012641 Pigmentation disease Diseases 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 238000004061 bleaching Methods 0.000 description 2
- 239000013043 chemical agent Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000004040 coloring Methods 0.000 description 2
- 238000005242 forging Methods 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 230000019612 pigmentation Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 239000008107 starch Substances 0.000 description 2
- 235000019698 starch Nutrition 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- JYLNVJYYQQXNEK-UHFFFAOYSA-N 3-amino-2-(4-chlorophenyl)-1-propanesulfonic acid Chemical compound OS(=O)(=O)CC(CN)C1=CC=C(Cl)C=C1 JYLNVJYYQQXNEK-UHFFFAOYSA-N 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 206010070834 Sensitisation Diseases 0.000 description 1
- 239000004133 Sodium thiosulphate Substances 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 238000013475 authorization Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-M bisulphate group Chemical group S([O-])(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-M 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000006255 coating slurry Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 150000002596 lactones Chemical class 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- PPNAOCWZXJOHFK-UHFFFAOYSA-N manganese(2+);oxygen(2-) Chemical class [O-2].[Mn+2] PPNAOCWZXJOHFK-UHFFFAOYSA-N 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000008313 sensitization Effects 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 235000012222 talc Nutrition 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
- D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
- D21H21/44—Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
- D21H21/48—Elements suited for physical verification, e.g. by irradiation
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
- D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
- D21H21/44—Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
- D21H21/46—Elements suited for chemical verification or impeding chemical tampering, e.g. by use of eradicators
Landscapes
- Paper (AREA)
- Heat Sensitive Colour Forming Recording (AREA)
- Inspection Of Paper Currency And Valuable Securities (AREA)
Abstract
A writing or printing medium, e.g. paper, for security documents contains a cobalt salt of oxidation degree 2 which reacts with sodium bisulphite to give an orange reaction. The salt may be a hydrated salt selected from the sulphate, chloride, acetate, nitrate or acetyl-acetonate and present in a concentration of 0.1-4%.
Description
PRINTING AND WRITING MEDIUM
The present invention relates to a printing or writing medium, particularly of paper, which is reactive to any attempt at falsification using chemical means and can be authenticated by heat.
It relates in particular to the field of security papers for use in making handwritten payment documents and official documents such as cheques, banknotes, Savings
Bank bonds, account passbooks, commercial accounts books, securities, stamped paper, notarial deeds, travel authorisations and, generally, to all security documents and articles comparable therewith, such as credit cards, etc.
For all such security papers it is necessary to guard against any attempt at falsification of the writing or stamp carried on these papers. The falsification may be mechanical (erasing or scraping) or chemical: with the aid of chemical agents which make it possible to eliminate cleanly the coloured inks at present in use for writing by hand or printing by inking rubber stamps.
Security papers are known which contain, in addition to the watermark and other physical security elements, such as wires, fibres, etc.! certain reagents contributing a sensitivity to chemical agents which may be used for falsifying writing by chemically decolouring the inks.
For example, papers have already been proposed which contain chemical substances reactive to chemical forging agents such as acids, alkalis, chlorinated bleaching agents such as chlorine water and Javel water, ink erasing pencils (FR-A-2 365 656, FR-A-2 399 505, FR-A-2 402 739, and FR-A-2 406 027), and oxidizing/reducing agents used in erasers of the "CORRECTOR" R type (EP-A-174 885).
However, the majority of commercially available security papers do not have a simple and reversible authentication process which can be combined with a protection against falsification.
The use of thermochromism for the authentication of security papers has been described in DE-A-1 228 972 and
AT-A-362 658. However, these processes require little utilized products which are costly and difficult to use in the papermaking industry. GB-A-l 565 243 describes authentication by thermochromism with the aid of thermo- chromic and thermomagnetic substances. Moreover, FR-A-2 597 897 describes a security paper which can be authenticated by thermochromism and which contains a violet lactone and an organic acid, but such a paper has a tendency to colour with time.
Furthermore, the protection of paper against forgeries must retain the non-fluorescent nature of the paper.
Indeed, fluorescence limits the security of these papers, as non-fluorescence is a very frequently used recognition sign, particularly with banks and the public at large. It is known that papers, particularly for writing and printing, are practically always fluorescent due to aids for improving the whiteness of the paper.
Given that supplies of non-fluorescent writing and printing paper are very closely supervised, forgers, unless they manage to obtain non-fluorescent paper, will, in all likelihood, use fluorescent paper. A non-fluorescent paper therefore affords a most effective safeguard against forgery and, when working on such a paper after having managed to make it non-fluorescent, it is obviously essential that the security agents incorporated into the paper should not themselves introduce the fluorescence characteristic which one had managed to avoid.
Among all the falsification agents, sodium bisulphite is an efficient reducing agent for deletion. It is used in deleting products of CORRECTOR R type, and can be very effective for shading out or bringing about the disappearance of blots caused by falsification of so-called "non-falsifiable" papers.
In "Verpackungs-Rundschau 11/1985 pp.1250-1253" a process is described for ascertaining the degree of humidity of air. Blotting paper is used, which is thus extremely absorbent, on which an anhydrous salt of blue cobalt chloride is deposited. As the paper absorbs the moisture of the air it turns pink. This paper must not be in contact with the perspiration of the hands to prevent unwanted moistening.
Furthermore, US-A-2 005 105 describes a paper which is reactive to bleaching or oxidizing agents, said paper being treated with an ink containing cobalt ferrocyanide.
In US -A-l 804 978 there is described a paper which is reactive to ink deletors, being treated with a solution comprising water, alcohol, iodine, cobalt nitrate and sodium thiosulphate.
DE-A-42 260 describes a paper reactive to chlorine-based deletors, said paper being treated with an ink containing a sulphated manganese oxide or cobalt chloride.
FR-A-1 509 715 describes a paper containing manganese ferrocyanide and a water-insoluble metallic salt, the paper being intended to1 react to bisulphate by forming a coloured ferrocyanide which imparts a colour to the paper. The metallic salt may be a transition metal salt.
Thus, according to these publications, transition metal salts are always used in combination with other salts to obtain either a reaction to bleaching or oxidizing agents, or a reaction to bisulphite. The specialist has therefore been led to associate metallic salts with other salts.
According to the invention, there is provided a medium for writing or printing, intended to be thermally authenticated, characterized in that at least one metallic salt which is coloured in the moist state and has a different colour in the dry state is incorporated in or on the medium, the dry weight quantity of the salt relative to the medium being such that the colouration of the medium at ambient temperature is substantially the colouration of the medium without the metallic salt, and that the colouration of the medium is reversibly changed when the temperature of the medium is raised.
It has been found, after intensive and lengthy tests, that by means of the invention a writing and printing medium can be obtained which has non-fluorescent security, can be reversibly thermally authenticated, is not appreciably coloured in its normal state, is compatible with other known reagents for sensitization to acids, bases, oxidizers, deleting pencils, and organic solvents, and is reactive to bisulphite.
Preferably, the metallic salt or salts incorporated in the medium in accordance with the invention are able to change from a crystalline state in one colour to a crystalline state of another colour, and are preferably cobalt salts of oxidation degree 2. Preferably the cobalt salt is a hydrated cobalt salt, preferably selected from the group comprising cobalt sulphate, cobalt chloride, cobalt acetate, cobalt nitrate, and cobalt acetyl-acetonate.
The writing or printing medium is preferably a cellulosefibre-based paper, or a plastic support coated with a layer enabling it to be printed or written on, and generally contains from 5 to 7% water after it has been through the drier. Given that the dry weight quantity of cobalt salt incorporated in the medium is low relative to the medium, preferably between 0.1 and 4Z, the cobalt salt remains in the hydrated state, even after the sheet of paper or other medium has been through the drier. In the case of cobalt chloride, this is then pink but the amount of it is sufficiently low not to impart any colouration to the paper which remains white.
Indeed, cobalt salts of oxidation degree 2 are generally coloured, but their introduction in relatively low quantities into paper does not affect the original colouring of the paper under normal conditions of dryness, and does not contribute fluorescence. At around 1000C such paper assumes a blue or violet colouring, which quickly fades away as soon as the paper is returned to ambient temperature. This colouration phenomenon, which is brought about by the presence of a cobalt salt of oxidation degree 2 in the paper, is visible only at high temperatures and therefore has no effect under normal daily conditions in which security papers are used. Thus, this colouration at the time of the dehydration of the paper may be used as an easy, non-destructive thermal authentication system for a security paper of this type.
The paper may be authenticated by localized heating, for example by means of heating jaws, blowing hot air, or a heating pen.
If desired, it is possible to add. a drying salt, such as sodium chloride, into the paper, which reduces the amount of water available and thereby lowers the temperature threshold of the colouration change.
Moreover, it has been observed, surprisingly, that the addition of cobalt salt 1to the paper results in a reaction (therefore providing protection) with several falsifying agents, such as hypochlorite, alkalis and sodium bisulphite. This reaction is obtained by introducing the cobalt salt on its own. Thus, the invention enables a thermally authenticatable and chemically non-falsifiable writing or printing medium to be obtained by introducing one compound only into the medium.
The medium in accordance with the invention may have any fibrous composition, purely cellulose-based or partly synthetic, from synthetic fibres or coated synthetic films, referred to briefly hereinunder as "paper'2, and may incorporate any of the additives standard in the stationery trade, such as mineral charges, various resistance agents, binders, resins, shading pigments, sizing products (neutral, acid or basic), alumina sulphate for acid sizing or pH adjustment, etc.
Since cobalt salts are generally very soluble, their introduction into the medium in accordance with the invention may be made by impregnation with the aid of sizing or coating equipment.
The reaction to heat of cobalt salts of oxidation degree 2 is perceptible to the naked eye at from 500 ppm of the salt in the medium, but, for very visible and fast reactivity, concentrations of between 0.15 and 4% cobalt of oxidation degree 2 are preferred.
Papers in accordance with the invention may also contain within their mass, in the dispersed pigmentary state, water-insoluble but organo-soluble pigments, with a view to preserving written entries or marks made on such papers in the event of attempts at forging using organic solvents. Moreover, these papers may be watermarked or may contain various devices intended to ensure recognition.
Thus, the invention enables manufacture of a white, nonfluorescent paper which is reversibly thermally authenticatable and which, in response to an attempt at chemical falsification, develops colourations detectable with the naked eye on the paper.
Paper in accordance with the present invention may be printed by any one of the known printing methods, and it is usable for handwriting when it is desired to secure permanence of the entries made, and the discovery of any future attempts at falsifying these handwritten entries.
It is particularly suitable for the production of handwritten non-fluorescent payment documents, such as cheques, cash vouchers, savings bank books, official deeds, banknotes, etc. I
Although most security papers used are white, it is also possible to make a security paper in accordance with the invention which is not white, but coloured.
Several examples of the medium in accordance with the invention will now be described by way of further, non-limiting, illustration.
EXAMPLE 1
A priting-writing paper has an aqueous coating solution deposited on its surface by a standard stationery technique (sizing press), the coating solution comprising, per litre of liquid: - 100 g starch - 15 g hexahydrated cobalt chloride.
A white paper is obtained which has an orange reaction to sodium bisulphite or to the subsequent addition of a solution of sodium bisulphite and permanganate.
0
The paper, if heated locally to about 100 C, assumes a blue tinge which disappears after a few minutes when heating has stopped.
EXAMPLE 2
A paper medium identical with that of Example 1 has an aqueous coating solution deposited on its surface by a standard stationery technique (sizing press), the aqueous coating solution containing, per litre of liquid: - 100 g starch - 15 g hydrated cobalt sulphate.
Results similar to those of Example 1 are obtained.
EXAMPLE 3
A paper medium is treated the same way as in Example 1 except that the coating solution contains 18 g of hydrated cobalt nitrate instead of cobalt chloride. Similar results are obtained.
EXAMPLE 4
A paper medium is treated the same way as in Example 1 except that the coating solution contains 15 g tetrahydrated cobalt acetate instead of cobalt chloride.
Similar results are obtained.
EXAMPLE 5
A paper medium is treated the same way as in Example 1 except that the coating solution contains 15 g cobalt acetyl acetonate instead of cobalt chloride. Similar results are obtained.
EXAMPLE 6
Banknote paper has a boating solution deposited on its surface by a standard stationery technique (sizing press), the coating solution containing, per litre of liquid:- - 100 g polyvinyl alcohol - 30 g hexahydrated cobalt chloride - 10 g sodium chloride.
A white paper is obtained which assumes a blue pigmentat ion beginning at 80 C. It is therefore easily authenticated by localized heating of the paper. The reaction is reversible in a few minutes after removal of the heat. Moreover, the paper has a strong orange reaction to bisulphite.
EXAMPLE 7
A high density polyethylene plastic medium is coated, using a standard paper technique (doctor blade, air brush, etc.), with an aqueous coating slurry containing, per litre of liquid: - 400 g dispersed charges (kaolin, talcum, carbonate) - 200 g latex - 30 g hydrated cobalt chloride.
The coated plastic is white, but on the application of heat a very clear blue pigmentation becomes visible.
Claims (7)
1. A medium for writing or printing, intended to be thermally authenticated, characterized in that at least one metallic salt which is coloured in the moist state and has a different colour in the dry state is incorporated in or on the medium, the dry weight quantity of the salt relative to the medium being such that the colouration of the medium at ambient temperature is substantially the colouration of the medium without the metallic salt, and that the colouration of the medium is reversibly changed when the temperature of the medium is raised.
2. A medium according to claim 1, in which the metallic salt is able to change from a crystalline state of one colour to a crystalline state of another colour, and is preferably a cobalt salt of oxidation degree 2.
3. A medium according to claim 2, in which the cobalt salt is a hydrated salt, preferably selected from the group comprising cobalt sulphate, cobalt chloride, cobalt acetate, cobalt nitrate, and cobalt acetyl-acetonate.
4. A medium according to any one of claims 1 to 3, in which the dry weight quantity of the metallic salt relative to the medium is between 0.1 and 4%.
5. A medium according to any one of the preceding claims, containing a siccative salt which lowers the temperature to which the medium is raised to alter its colouration.
6. A medium according to claim 5, in which the siccative salt is sodium chloride.
7. A process according to claim 6, characterized in that the cobalt salt is deposited onto the surface of the medium by a standard paper-making technique from an aqueous coating solution containing said salt.
7. A medium according to any one of the preceding claims, which is reactive to bisulphite so that it cannot be falsified by sodium bisulphite.
8. A medium according to any one of the preceding claims, in which the metallic salt is deposited onto the surface of the medium by a standard paper-making technique from an aqueous coating solution containing said metallic salt.
9. A medium according to claim 1, substantially as herein described in any one of Examples 1 to 7.
10. A security document or article comprising a medium according to any one of the preceding claims.
CLAIMS 1. A medium for writing or printing reacting with sodium bisulphite, characterized in that it contains a cobalt salt of oxidation degree 2.
2. A medium according to claim 1, characterized in that said cobalt salt is an hydrated cobalt salt.
3. A medium according to claim 1 or 2, characterized in that said cobalt salt is selected from the group comprising cobalt sulphate, cobalt chloride, cobalt acetate, cobalt nitrate and cobalt acetyl-acetonate.
4 A medium according to anyone of claims 1 to 3 characterized in that it has an orange reaction to sodium bisulphite.
5. A medium according to anyone of claims 1 to 4, chracterized in that it contains from 0,1 to 4 % of hydrated cobalt salt of oxidation degree 2.
6. A process of protection of a medium for writing or printing against chemical falsification, characterized in that it consists in introducing in or onto the surface of said medium an hydrated cobalt salt of oxidation degree 2 in order to have an orange reaction in presence of sodium bisulphite.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9102451A GB2240511B (en) | 1987-09-03 | 1991-02-20 | Printing and writing medium |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR878712243A FR2620146B1 (en) | 1987-09-03 | 1987-09-03 | MEANS, PAPER AND SECURITY DOCUMENT AGAINST CHEMICAL FALSIFICATION AND COUNTERFEITING |
GB8820751A GB2209304B (en) | 1987-09-03 | 1988-09-02 | Printing and writing medium |
GB9102451A GB2240511B (en) | 1987-09-03 | 1991-02-20 | Printing and writing medium |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9102451D0 GB9102451D0 (en) | 1991-03-20 |
GB2240511A true GB2240511A (en) | 1991-08-07 |
GB2240511B GB2240511B (en) | 1992-05-13 |
Family
ID=9354600
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8820751A Expired - Fee Related GB2209304B (en) | 1987-09-03 | 1988-09-02 | Printing and writing medium |
GB9102451A Expired - Fee Related GB2240511B (en) | 1987-09-03 | 1991-02-20 | Printing and writing medium |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8820751A Expired - Fee Related GB2209304B (en) | 1987-09-03 | 1988-09-02 | Printing and writing medium |
Country Status (9)
Country | Link |
---|---|
BE (2) | BE1011816A4 (en) |
CH (2) | CH679411A5 (en) |
DE (1) | DE3829002C3 (en) |
DK (2) | DK487888A (en) |
ES (1) | ES2008020A6 (en) |
FR (3) | FR2620146B1 (en) |
GB (2) | GB2209304B (en) |
IT (1) | IT1226420B (en) |
NL (2) | NL191211C (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1024874A (en) * | 1963-10-04 | 1966-04-06 | Birmingham Small Arms Co Ltd | Improvements in or relating to rotary piston internal combustion engines |
FR2639970B1 (en) * | 1988-12-07 | 1991-09-20 | Aussedat Rey | NON-FLUORESCENT, NON-FLUORESCENT SECURITY PAPER AND DOCUMENT OBTAINED |
GB2274428B (en) * | 1993-01-20 | 1996-08-21 | Portals | Security threads |
DE19833746A1 (en) * | 1998-07-27 | 2000-02-03 | Joergen Brosow | Security paper and method for checking authenticity of documents recorded on it protects securities like bank notes against forgery by using embedded electronic switching circuit |
FR2943074B1 (en) * | 2009-03-13 | 2011-05-20 | Arjowiggins Security | LASER MARKABLE SUBSTRATE AND METHOD FOR MANUFACTURING THE SAME |
CN103730071B (en) * | 2013-12-30 | 2017-05-03 | 深圳市华星光电技术有限公司 | OLED panel, manufacturing method thereof and encapsulation effect detection method |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE42260C (en) * | 1900-01-01 | A. ZEISS in Berlin W., Charlottenstr. 68 | Manufacture of security paper | |
DE115445C (en) * | ||||
US1804978A (en) * | 1926-03-01 | 1931-05-12 | Genoese John | Safety paper |
US2005105A (en) * | 1930-06-23 | 1935-06-18 | Milton C Johnson Company | Safety paper |
DE660599C (en) * | 1934-02-08 | 1938-05-31 | Felix Schoeller & Bausch | Process for the production of security paper |
DE1228972B (en) * | 1959-06-06 | 1966-11-17 | Dr Karlheinz Koenig | Identification of authenticity of securities |
FR1509715A (en) * | 1966-02-04 | 1968-01-12 | Inveresk Paper Company Ltd | Security paper |
FR2365656A1 (en) * | 1976-05-25 | 1978-04-21 | Arjomari Prioux | SECURITY PAPER |
FR2402739A2 (en) * | 1976-05-25 | 1979-04-06 | Arjomari Prioux | Security paper for handwritten cheques and documents - impregnated with salts of pyrene-sulphonic acids |
FR2399505A1 (en) * | 1976-05-25 | 1979-03-02 | Arjomari Prioux | Security paper for prepn. of official documents etc. - is coated with or contains oxy:pyrene-tri:sulphonic acid or a salt of the acid |
FR2406027A1 (en) * | 1977-10-14 | 1979-05-11 | Voiron Papeteries | Security paper treated with a nitrophenol - showing, in a range of colours from yellow to violet, any attempt at alteration using alkaline media |
GB1565243A (en) * | 1977-12-02 | 1980-04-16 | Emi Ltd | Recording data in eye-visible and machine readable magnetic form |
AT362658B (en) * | 1978-03-15 | 1981-06-10 | Oesterr Nationalbank | PAPER, METHOD FOR TESTING PAPERS AND DEVICE FOR CARRYING OUT THE TEST METHOD |
JPS5787396A (en) * | 1980-11-18 | 1982-05-31 | Sadao Nishi | Chemical agent for marking paper money |
NO158550C (en) * | 1986-03-26 | 1988-09-28 | Niels A Andersen | USE OF A SUBSTANCE FOR DISPOSAL OF COPY OF THE DOCUMENT. |
FR2797895B1 (en) * | 1999-09-01 | 2001-11-09 | Mathieu Yno S A | SELF-CLEANING CYLINDRICAL BRUSH FOR SWEEPERS OR OTHER VEHICLES |
-
1987
- 1987-09-03 FR FR878712243A patent/FR2620146B1/en not_active Expired - Fee Related
-
1988
- 1988-08-26 DE DE3829002A patent/DE3829002C3/en not_active Expired - Lifetime
- 1988-08-30 IT IT8821782A patent/IT1226420B/en active
- 1988-08-30 BE BE8800982A patent/BE1011816A4/en not_active IP Right Cessation
- 1988-09-02 ES ES8802711A patent/ES2008020A6/en not_active Expired
- 1988-09-02 CH CH498/91A patent/CH679411A5/fr not_active IP Right Cessation
- 1988-09-02 GB GB8820751A patent/GB2209304B/en not_active Expired - Fee Related
- 1988-09-02 DK DK487888A patent/DK487888A/en not_active Application Discontinuation
- 1988-09-02 NL NL8802167A patent/NL191211C/en not_active IP Right Cessation
- 1988-09-02 CH CH3291/88A patent/CH677241A5/fr not_active IP Right Cessation
-
1989
- 1989-02-24 FR FR898902382A patent/FR2643661B1/en not_active Expired - Lifetime
-
1990
- 1990-12-11 FR FR909015510A patent/FR2654446B1/en not_active Expired - Fee Related
-
1991
- 1991-01-30 BE BE9100085A patent/BE1011817A4/en not_active IP Right Cessation
- 1991-02-19 DK DK028391A patent/DK28391D0/en not_active Application Discontinuation
- 1991-02-20 GB GB9102451A patent/GB2240511B/en not_active Expired - Fee Related
- 1991-03-08 NL NL9100419A patent/NL9100419A/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
CH677241A5 (en) | 1991-04-30 |
DK487888D0 (en) | 1988-09-02 |
BE1011816A4 (en) | 2000-02-01 |
ES2008020A6 (en) | 1989-07-01 |
BE1011817A4 (en) | 2000-02-01 |
NL9100419A (en) | 1991-06-03 |
DE3829002A1 (en) | 1989-03-16 |
FR2643661A1 (en) | 1990-08-31 |
FR2620146A1 (en) | 1989-03-10 |
FR2654446B1 (en) | 1992-10-16 |
GB2209304A (en) | 1989-05-10 |
DK487888A (en) | 1989-03-04 |
FR2654446A1 (en) | 1991-05-17 |
IT8821782A0 (en) | 1988-08-30 |
DK28391A (en) | 1991-02-19 |
DK28391D0 (en) | 1991-02-19 |
GB2209304B (en) | 1992-05-13 |
GB9102451D0 (en) | 1991-03-20 |
FR2620146B1 (en) | 1991-10-04 |
NL191211B (en) | 1994-10-17 |
FR2643661B1 (en) | 1991-05-10 |
IT1226420B (en) | 1991-01-15 |
NL8802167A (en) | 1989-04-03 |
GB8820751D0 (en) | 1988-10-05 |
CH679411A5 (en) | 1992-02-14 |
DE3829002C2 (en) | 1995-01-05 |
DE3829002C3 (en) | 1997-09-04 |
NL191211C (en) | 1995-03-16 |
GB2240511B (en) | 1992-05-13 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19980902 |