Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/28—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating
  • B41M5/282—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating using thermochromic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/50—Sympathetic, colour changing or similar inks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/28—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating
  • B41M5/282—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating using thermochromic compounds
  • B41M5/283—Inorganic thermochromic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/28—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating
  • B41M5/282—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating using thermochromic compounds
  • B41M5/284—Organic thermochromic compounds

Definitions

• the present invention relates to the field of the printing of a surface by an ink, and / or the treatment of the printing of this surface by such an ink.
• the invention generally relates to a printing treatment of a surface by an ink.
• Document EP-2110417 also discloses a method of photo-catalysis of the ink but whose duration is of the order of 16 hours to recover a blank page.
• the abovementioned compound is preferably in the form of nanometric particles, advantageously suited to inkjet printing techniques.
• the present invention firstly aims at a process for printing a surface with an ink, and in particular, this ink comprises such a compound with a change of spin state.
• ambient temperature means a normal temperature of use of the ink, for common office printing applications for example, such a temperature then being typically close to or of the order of 20 ° C.
• the visibility of the ink as a function of temperature follows a hysteresis cycle, the ink being:
• the above-mentioned temperature "outside the range” is higher than the temperatures of the range and the heat treatment then corresponds to heating the ink.
• the ink once made transparent after heating, can be brought back to room temperature where it remains permanently invisible.
• the heat treatment to make it invisible only lasts a few seconds. For example, five seconds are sufficient.
• the method may then comprise a heat treatment of the surface comprising printing with the ink to make the ink transparent in the visible.
• the duration of the treatment is of the order of only a few seconds (as opposed to more than 16 hours in the prior art EP-2110417 presented above).
• a heat treatment by raising the temperature between 50 and 100 ° C makes the ink invisible.
• Such temperatures are perfectly compatible with the application of the invention to the printing of the ink on standard weight paper sheets.
• the temperature threshold below which the ink can become visible again can be of the order of -150 to -200 ° C.
• the ink, once erased, can hardly reappear at a "normal" use temperature (around room temperature).
• this threshold may be of the order of 10 ° C., depending on the hysteresis of the particular material chosen.
• This embodiment advantageously has the advantage of making the ink reappear easily, especially in applications related to security.
• the ink can become visible again by lowering the temperature, at a low lower temperature or on the order of 10 ° C.
• the low temperature can be even lower and, in particular, be lower or of the order of -150 ° C.
• a material exhibiting such general properties of change in optical behavior, according to a temperature hysteresis and having given satisfactory results, contains for example at least one type of molecule of the family of triazoles.
• This molecule comprises a transition metal of electronic configuration 3d 4 , 3d 6 and / or 3d 7 and nitrogen ligands of which at least one ligand comprises a triazole.
• at least one ligand comprises a molecule of water bonded to this ligand by a hydrogen bond.
• such a compound can be obtained in the form of nanometric particles.
• the particles are not large enough to induce excessive optical diffusion, which may disturb the optical properties of the ink in the visible and, of course, this nanoscale particle makes this material a prime candidate to be the basis of an ink for jet printing from nozzles for example.
• Document FR-2,917,410 discloses (page 20, lines 20-30 of this document) the preparation of an emulsion whose size of water drops determines the size of the molecules polymerized in a micellar medium, with ultrasonic application for a single purpose of mixing (as a vortex effect), while the application of ultrasound in the sense of the invention has the effect of "breaking" the particles to reduce them to a nanoscale size. While in the document cited FR-2,917,410, to produce 1 gram of particles, the micellar pathway with a surfactant typically requires the use of 100 ml of ethyl ether to denature the emulsion and then three washes with 100 ml of ether.
• the present invention advantageously allows to produce a quantity of nanoparticles of 1 g of final product with just three washes in 5 mL of water.
• micellar particle synthesis of document FR-2,917,410 is in fact difficult to transpose for large-scale production, particularly because of the large amounts of solvent involved, whereas ultrasound synthesis is much more difficult. adaptable.
• the present invention also relates to a process for manufacturing a compound containing at least one molecule comprising a transition metal of electronic configuration 3d 4 , 3d 6 and / or 3d 7 and nitrogen ligands comprising at least one triazole ligand .
• a method comprises a synthesis of the aforementioned molecule, this synthesis being in particular assisted by ultrasound incidence.
• the present invention thus also aims at an ink for printing a surface, and comprising in particular an electronic spin state change compound as a function of temperature, conferring optical properties such that said ink is:
• such a compound has a particle size at the nanoscale, as indicated above.
• the present invention also relates to a cartridge comprising such an ink. It will be understood in particular that, given the fluidity of the ink in the sense of the invention, it is fully compatible with the currently known inkjet techniques and no development is necessary for its incorporation and use in a conventional ink cartridge.
• the present invention also relates to a printing device comprising at least one such cartridge.
• a printing device comprising at least one such cartridge.
• such a device may comprise ink jet means on the aforementioned surface. It can then be a printer without any particular arrangement, the ink within the meaning of the invention being perfectly compatible with this type of inkjet printing technique.
• the present invention also provides a device comprising means for driving a surface printed with an ink according to the invention, up to a heat treatment chamber that this device comprises, to make the ink invisible, as indicated. above.
• a device can be integrated with a printing device of the aforementioned type.
• one possible embodiment would be a "photocopier" type printing device comprising an ink cartridge within the meaning of the invention for printing ink on a sheet, as well as a heat treatment chamber. to make the ink invisible on other sheets to recycle.
• the aforementioned heat treatment may be conducted by laser irradiation from a laser source having a wavelength in an optical absorption band of the ink.
• this wavelength can be in the infrared range, to selectively heat the aforementioned molecules and to generate the spin transition more easily and without necessarily raising the temperature of all the ink and paper to that where the spin transition takes place.
• the device comprising the aforementioned heat treatment chamber may incorporate such a laser source.
• FIG. 1 illustrates the spin transition phenomenon for the iron (II) ion, with in particular an evolution of the high spin fraction (HS) as a function of temperature for an increasingly cooperative system
• FIG. 2 illustrates an example of a hysteresis cycle of a material that is suitable for a "reversible" ink and that can be visible below 10 ° C. and invisible above 60 ° C.,
• FIG. 3 illustrates an example of an "apparent" hysteresis cycle of a material that is suitable for an "irreversible” ink and exhibits a true hysteresis cycle only below -160 ° C.
• FIG. 4 schematically illustrates a process for synthesizing such a material, in particular assisted by ultrasound incidence
• FIG. 5 diagrammatically illustrates an ink in a cartridge of a printing device in the sense of the invention, as well as a device for heat treatment of an ink-printed surface, by laser scanning, to render the ink invisible ink.
• the invention proposes the use of a spin-transition material as a thermochromic pigment within an ink.
• the spin transition phenomenon can be encountered in a coordination complex containing a transition metal of electronic configuration 3d 4 , 3d 6 or 3d 7 and ligands of nitrogen type.
• the compounds In the macroscopic state, the compounds are in the form of crystals or polymers.
• the spin state transition is manifested by an important modification of the mechanical, dielectric, magnetic and optical properties.
• An advantage of these compounds for the implementation of the invention is to present a thermal hysteresis.
• the transition temperature is adjustable depending on the nature of the material.
• the scale of the material inserted into the ink can be typically from a few microns to about ten nanometers in order to optimize the visual rendering, the viscosity of the ink, the "oil” setting, or others.
• the materials can be obtained at the nanoscale (particle size of 20 to 200 nm), having various possible colors and with adjustable transition temperatures. It has been observed a good chemical compatibility and a perfect preservation of the switching properties. The ultraviolet resistance of these inks after deposits has also been verified.
• thermochromic ink possible applications also in the field of security and / or traceability, - possible applications also to the modification of the color of a light source (for example an LED-type lamp) with the aid of such a thermochromic ink
• protection layers filter type controllable by an external stimulus (temperature, pressure, light, gas, or other).
• the measurement of the switching temperature can ensure in itself an authentication and / or traceability of the product to be protected .
• the ink can become transparent and thus reveal information inscribed in the underlayer.
• R1-Trz and R2-Trz are 1,2,4-triazole ligands bearing a substituent R1 comprising an alkyl group-OH and R2 an alkyl group or a group R1'R2'N in which R1 'and R2' each independently represent the other a hydrogen atom H or an alkyl radical,
• Xb represents 3-nitrophenyl sulfonate
• Yc represents at least one anion which has a dye group, which advantageously makes it possible to obtain a set of two "colors" which can be chosen according to the intended application.
• one of the colors is in the visible in the low spin state and the other "color", in the high spin state, is out of the visible, for example in the infrared as will be seen in an embodiment described below.
• a process for obtaining a compound of this type in the form of nanoparticles is described in document FR-2,894,581. Its encapsulation to increase the hysteresis effect (spreading the rising and falling edges in temperature) is described in document FR-2,917,410.
• FIG. 2 shows an example of variation of the optical re-emission properties as a function of temperature, according to a typical hysteresis cycle of this material.
• the ink Below 10 ° C and for a first application of the ink to less than 60 ° C, the ink is visible and emits a wavelength ( ⁇ ) in the visible spectrum, so between 0.4 and 0 65 micrometer (reference screw of Figure 2).
• ⁇ wavelength
• the ink becomes “invisible”: in fact, it emits optically in the infrared, so more than 0.65 micrometer (reference Hvis of Figure 2).
• By lowering the temperature again for example up to 20 ° C, it remains “invisible” on the Hvis top plate of Figure 2. Then, if the temperature decreases beyond 10 ° C, the ink becomes again visible, on the low plateau of Figure 2.
• this network comprises at least one molecule of water bound to the ligand by a hydrogen bond.
• the metal is constituted by one or more metal ions having an electronic configuration in d 4 , d 5 , d 6 or d 7 in which the ligand is a substituted 1-2-4 triazole, the substitution radical of which comprises an alcohol group (alkyl-OH type), and in which flag is an organic derivative of both tosilate and sulfate.
• the metal is the iron ion Fe (electronic configuration in d6) or an iron-zinc alloy,
• the ligand is a 4- (2'-hydroxyethyl) -1,2,4 triazole, and
• flag is a 3-nitro-phenylsulfonate.
• such a material has the particularity of benefiting from an "apparent" hysteresis.
• a spin transition occurs at a temperature of the order of 100 ° C. (or even lower, here at 95 ° C.), this transition being irreversible in temperature ranges close to ambient.
• the optical properties associated with this transition correspond to the transition from a color in the visible to an optical emission out of the visible.
• the actual hysteresis cycle is, in fact, in very low temperatures (between -170 and -165 ° C). The ink can again appear in the visible at -170 ° C and become invisible this time at -165 ° C.
• the ink is durably erasable by raising the temperature to about 100 ° C, and is substantially irreversible under normal use conditions of an ink.
• a first irreversible transition temperature of the low spin (emission in the visible screw) to the high spin (emission out of the visible, Hvis, for example in the infrared) is for example 95 ° C (dotted line curve of Figure 3).
• the temperatures of high spin Hvis transitions to low spin spin and reversibly low spin high spin Hvis spin again are respectively around -170 ° C and -165 ° C.
• the thermal switching irreversibly causes the transition from the initial low spin state (screw plateau) to the high spin state of the material (Hvis plateau).
• This spin transition property of such a material could be explained by a transformation of the bond involving the water molecule and its ligand, around 100 ° C.
• the flask containing the ligand is then added to the reaction medium containing the iron salt and ultrasound is then applied for 15 minutes at 50 ° C. After one night, the whole is sintered and a pink powder having the temperature hysteresis properties shown in FIG. 3 is obtained.
• thermochromic ink obtained in an exemplary embodiment of the invention, deposited on paper can:
• FIG. 5 shows a cartridge CAR within the meaning of the invention comprising such an ink ENC, which can be injected by one or more BU nozzles onto a printing surface such as a sheet of paper PA.
• This arrangement can be provided in a DIS device, of the printer or photocopier type, including in particular first drive means ENT1 of the sheet.
• the device DIS may also include a heat treatment chamber comprising a laser source LAS and means for scanning a ray from this source, on the surface of a sheet of PA paper to make the ink invisible.
• second drive means ENT2 are provided up to this heat treatment chamber.
• the grouping of the printing device of FIG. 5 and the laser scanning heat treatment device can be arranged in separate respective entities, rather than forming part of the same common structure.
• Two types of materials have been described above with reference to FIGS. 2 and 3, having respective distinct hysteresis. However, it is possible to envisage a mixture of these two materials in the same ink, for example the visible color of the "reversible" material being sufficiently clear not to be well seen below 10 ° C.
• transition temperature thresholds are given above by way of non-limiting examples.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Printing Methods (AREA)
• Ink Jet (AREA)

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• 2010
  • 2010-07-22 FR FR1055976A patent/FR2963016B1/fr active Active
• 2011
  • 2011-07-21 JP JP2013520193A patent/JP5993851B2/ja not_active Expired - Fee Related
  • 2011-07-21 WO PCT/FR2011/051767 patent/WO2012010807A2/fr active Application Filing
  • 2011-07-21 US US13/810,515 patent/US9193203B2/en not_active Expired - Fee Related
  • 2011-07-21 EP EP11752270.6A patent/EP2596069A2/de not_active Withdrawn

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