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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/355—Security threads
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
  • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives
  • D01F2/28—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate

Definitions

• the invention relates to a security paper with luminescent embeddings such as mottled fibers or security. threads.
• security paper is understood to mean not only banknotes and other monetary documents such as checks, check cards, credit cards, but also other particularly secured documents such as identity cards and the like.
• Such papers whose commercial or use value far exceeds the material value, must be recognizable as genuine by suitable measures and distinguishable from counterfeiting and counterfeiting.
• Measures that have proven particularly useful in the past include embedding security threads and luminescent mottled fibers in the paper stock.
• Such fibers are easy to imitate because commercially available emulsions can be used to produce electrically conductive or magnetizable coatings by immersing the fiber in these emulsions and then drying them in air; for falsification of impressions in many cases a pencil line is sufficient as a replacement for an electrically conductive fiber or a line with a commercially available felt tip pen containing magnetizable ink for a magnetizable fiber.
• luminescent embeddings can rather be designed in such a way that, although they are easy and simple to detect, the luminescent substances themselves are neither commercially available nor can they be produced using the means available to the counterfeiters.
• Chelates of the lanthanides are used as luminophores (i.e. the elements with atomic numbers 58-71 in the periodic table of the elements).
• luminophores are characterized by a particularly narrow-band emission.
• the line-emitting luminophores are mixed with a printing ink and thus printed on the document. If certain luminophores or their emission lines are present or absent, coded information is recorded which can serve as an authenticity indicator.
• the emission occurs in the visible range of the optical spectrum; emission lines in the near infrared are also used to expand the usable spectral range.
• the object of the invention is therefore to propose luminescent mottled fibers and / or security threads for security papers that are clearly identifiable and are difficult to manufacture due to their technology.
• the concentration of the luminophores in the fibers should therefore be so high that a visual authenticity check is possible even in daylight conditions.
• security paper is equipped with narrow-band luminescent mottling fibers or security threads made of cellulose acetate; the luminophores used are lanthanide chelates, the luminophore used in each case is dissolved uniformly and with a high concentration in the volume of the cellulose acetate fiber.
• the luminescent fiber is colorless and detects intensively in the red after excitation with UV light.
• cellulose acetate is dissolved in acetone and mixed with an acetone solution of a lanthanide chelate.
• the lanthanide chelates used are soluble in acetone up to high concentrations; Experiments have achieved solubilities of 68% (weight) in acetone.
• the mixture of the solution mentioned prepared in this way is then spun into a fiber in a manner known per se.
• the fiber of this invention is preferably colorless and transparent; however, it can also be set to white or colored by additives in a manner known to those skilled in the art.
• the fiber For use as mottled fiber, the fiber is now generally crimped and cut to a length of 3 to 4 mm.
• the mottled fibers thus obtained can then be added to the pulp of a paper machine by known methods without further treatment.
• the spun material is advantageously twisted or woven into a thread; it has proven to be extremely difficult to directly obtain threads of sufficient thickness with the spinning process used.
• the security thread with information if it is twisted or woven from different luminescent individual fibers.
• the presence or absence of certain luminophores - recognizable by the presence or absence of certain emission lines or colors - then form the coded information; this can e.g. B. specify the value of banknotes.
• a particularly striking advantage of these fibers according to the invention is that the luminophore content could be increased by a factor of 20 compared to the prior art.
• the Lumines has increased accordingly intensity. This surprising effect is caused by the extremely high solubility of the lanthanide chelates in acetone, which has already been mentioned above.
• a fiber can be dissolved or dissolved with acetone to check the authenticity of the security paper according to the invention; the luminophore also releases and "bleeds" into the paper stock. A correspondingly wide spot can therefore be seen under the UV lamp, which can be used as an authenticity criterion. Because the stain is not visible under room or daylight, security paper tested in this way can then be put back into circulation. Such an authenticity check cannot be carried out with known mottled fibers. Another important advantage results from the narrow-band nature of the luminescence emission of fibers according to the invention. So z. B. preferably a Europium-ß-diketone chelate with a concentration of 5% (weight) is used in a transparent cellulose acetate fiber.
• this fiber When excited with ultraviolet light, this fiber shows a very intense emission in the red; the corresponding emission line only has a spectral width of 5 nm.
• the printed image it is therefore only necessary to keep a narrow spectral range free for reliable recognition of the authenticity mark.
• this invention is the first to produce a colorless fiber that luminesces strongly in red. Mottled fibers with conventional, broadband fluorescence, on the other hand, always have a body color and can therefore already be seen with the naked eye.
• the invention is in no way limited to fibers and threads with luminescence emission in the visible.
• Example 2 describes a lanthanide chelate which emits exclusively in the infrared but otherwise has the same properties with regard to the invention as the luminophores emitting in the visible.
• the use of such mottled fibers or security threads is such.
• B. advantageous if one does not want to make the authenticity check understandable by everyone for given reasons. In such devices, the emitted light is detected and evaluated by appropriate IR photo detectors or also by IR image converters.
• a suitable test device for the detection of luminescent mottled fibers is e.g. B. described in DE-AS 20 37 755; it only has to be adapted to the luminophore used by appropriate selection of the filter and the photo receiver.
• R and R ' can be the same or different or can also be parts of a cyclic product: z. B.
• a 30% acetone solution is prepared from the synthesized chelate, and this is then added to an acetone solution of cellulose acetate. Then the mixture is pressed through a nozzle into a heated chute and thus spun into an endless thin fiber of cellulose acetate, which contains the luminophore up to a proportion of 10% (weight) in volume. The fiber is then crimped and cut into sections approximately 3 mm in length. The mottled fibers thus produced luminesce intensely at 610 nm when they are irradiated with ultraviolet light; the fibers are lightfast to WS3 and resistant to petrol, benzene, ether and oils.
• the fibers are added to the pulp of a paper machine in a known manner.
• the corresponding chelate is prepared as described in Example 1, but using a mole of NdCl 3 .6H 2 O instead of 1 mole of EuCl 3 .6H 2 O.
• a 30% acetone solution is again produced from the chelate synthesized in this way, this is mixed with an acetone solution of cellulose acetate and spun into a fine fiber. Then several of these fibers are woven into a thread 0.5 mm wide. This thread is colorless and luminescent intensely in the infrared at 1.06 ⁇ m after excitation with visible light; it is lightfast and resistant to petrol, benzene, ether and oils.
• To produce a corresponding security paper it is guided on a double-round paper machine from a roll between the two layers of the sheet that is formed and is thus enclosed by the paper stock.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Paper (AREA)
• Credit Cards Or The Like (AREA)
• Thermotherapy And Cooling Therapy Devices (AREA)
• Details Of Garments (AREA)
• Inspection Of Paper Currency And Valuable Securities (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

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ID=6134067

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Cited By (24)

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Citations (4)

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• 1981
  • 1981-06-05 DE DE3122470A patent/DE3122470C2/de not_active Expired
• 1982
  • 1982-06-03 EP EP82104887A patent/EP0066854B1/fr not_active Expired
  • 1982-06-03 AT AT82104887T patent/ATE12532T1/de not_active IP Right Cessation
  • 1982-06-04 ES ES514027A patent/ES8400524A1/es not_active Expired
  • 1982-06-04 JP JP57095026A patent/JPS5854099A/ja active Pending

Patent Citations (4)

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