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
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/385—Contact thermal transfer or sublimation processes characterised by the transferable dyes or pigments
  • B41M5/388—Azo dyes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/913—Material designed to be responsive to temperature, light, moisture
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/914—Transfer or decalcomania

Definitions

• the present invention relates to a new method for transferring azo dyes, which have a thiophene-based diazo component, from a support onto a plastic-coated paper with the aid of a thermal head.
• a transfer sheet which contains a thermally transferable dye in one or more binders, optionally together with suitable auxiliaries, on a support is heated with a heating head with short heating pulses (duration: fractions of a second) from the back, whereby the dye migrated from the transfer sheet and diffused into the surface coating of a recording medium.
• the main advantage of this method is that it is easy to control the amount of dye to be transferred (and thus the color gradation) by adjusting the energy to be delivered to the heating head.
• EP-A-216 483 and EP-A-258 856 describe azo dyes which have thiophene-based diazo components and aniline-based coupling components.
• disazo dyes based on thiophene and aniline are known from EP-A-218 937 for this purpose.
• the object of the present invention was to provide a process for the transfer of dyes, the dyes being intended to meet the above requirements i) to vii) as well as possible.
• azo dyes of the formula I are in the R1 and R2 are the same or different and are each independently alkyl, alkanoyloxyalkyl, alkoxycarbonyloxyalkyl or alkoxycarbonylalkyl, the radicals each having up to 20 carbon atoms and by phenyl, C1-C4-alkylphenyl, C1-C4-alkoxyphenyl, benzoyloxy, C1-C4- Alkylbenzyloxy, C1-C4-alkoxybenzyloxy, halogen, hydroxy or cyano may be substituted, hydrogen, phenyl optionally substituted by C1-C20-alkoxy or halogen, optionally substituted by C1-C20-alkyl, C1-C20-alkoxy or halogen-substit
• Residues Y in formula I are e.g. Ethylene, 1,2- or 1,3-propylene, 1,2-, 1,3-, 1,4- or 2,3-butylene, pentamethylene, hexamethylene or 2-methylpentamethylene.
• Suitable radicals R1, R2, R3, R4 and R6 in formula I are e.g. Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl.
• R1, R2 and R3 are further e.g. Pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl or isodecyl.
• Residues R1 and R2 are furthermore, for example, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or eicosyl.
• the designations isooctyl, isononyl, isodecyl and isotridecyl are trivial designations and come from the alcohols obtained after oxosynthesis (cf. Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, volume 7, pages 215 to 217 and volume 11, pages 435 and 436 ).
• Residues R3 are further e.g. Pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, heptyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy or decyloxy.
• Residues R4 are still e.g. Methylthio, ethylthio, propylthio, isopropylthio or butylthio.
• R1 and R2 are furthermore, for example, benzyl, 1- or 2-phenylethyl,
• the new process uses a carrier on which there are one or more azo dyes of the formula I in which
• R1 and R2 independently of one another C1-C12-alkyl, which is optionally substituted by cyano, phenyl, C1-C4-alkylphenyl or C1-C4-alkoxyphenyl, or a radical of the formula III [-CH2-CH2-O] R7 (III), wherein n for 1, 2, 3 or 4 and R7 is C1-C4 alkyl or phenyl, R3 is hydrogen, methyl, methoxy or acetylamino, R4 chlorine and R5 cyano or the radical -CO-OR1, -CO-NHR1 or -CO-NR1R2, where R1 and R2 each have the latter meaning given above.
• the dyes of the formula I are known from EP-A-201 896 or can be obtained by the methods mentioned there.
• the dyes transferred in the process according to the invention are generally distinguished by improved migration properties in the recording medium at room temperature, easier thermal transferability, higher photochemical stability, easier technical accessibility, better resistance to moisture and chemical substances, higher color strength , better solubility and especially from higher color purity.
• the dyes are in a suitable organic solvent, for. B. chlorobenzene, isobutanol, methyl ethyl ketone, methylene chloride, toluene, tetrahydrofuran or mixtures thereof with one or more binders, optionally with the addition of auxiliaries, processed into a printing ink.
• a printing ink contains the dye preferably in a molecularly dispersed, dissolved form.
• the printing ink is applied to the inert carrier using a doctor blade and the dyeing is air-dried.
• All resins or polymer materials which are soluble in organic solvents and are capable of binding the dye to the inert support in an abrasion-resistant manner are suitable as binders.
• All resins or polymer materials which are soluble in organic solvents and are capable of binding the dye to the inert support in an abrasion-resistant manner are suitable as binders. Thereby such Preference is given to binders which absorb the dye in air in the form of a clear, transparent film after the printing ink has dried, without any visible crystallization of the dye occurring.
• binders are cellulose derivatives, e.g. B. methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate or cellulose acetobutyrate, starch, alginates, alkyl resin, vinyl resin, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyrate or polyvinyl pyrrolidone.
• cellulose derivatives e.g. B. methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate or cellulose acetobutyrate, starch, alginates, alkyl resin, vinyl resin, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyrate or polyvinyl pyrrolidone.
• Polymers and copolymers of acrylates or their derivatives such as polyacrylic acid, polymethyl methacrylate or styrene-acrylate copolymers, polyester resins, polyamide resins, polyurethane resins or natural CH resins, such as gum arabic, are also suitable as binders. Further suitable binders are described in DE-A-3 524 519.
• Preferred binders are ethyl cellulose or ethyl hydroxyethyl cellulose of medium to small viscosity settings.
• the ratio of binder to dye preferably varies between 5: 1 and 1: 1.
• auxiliaries such as are specified in EP-A-227 092, EP-A-192 435 or the patent applications cited therein, are also suitable as auxiliaries, in addition, in particular, organic additives which cause the transfer dyes to crystallize out during storage and when the ink ribbon is heated prevent e.g. B. cholesterol or vanillin.
• Inert carriers are e.g. B. tissue, blotting paper or glassine paper or plastic films with good heat resistance, e.g. B. optionally metal-coated polyester, polyamide or polyimide.
• the inert carrier is optionally additionally coated with a slip layer on the side facing the thermal head in order to prevent the thermal head from sticking to the carrier material.
• Suitable lubricants are e.g. B. described in EP-A-216 483 or EP-A-227 095.
• the thickness of the dye carrier is generally 3 to 30 microns, preferably 5 to 10 microns.
• thermostable plastic layers with an affinity for the dyes to be transferred can be used as the dye-receiving layer.
• Your glass transition temperature should be below 150 ° C.
• Modified polycarbonates or polyesters may be mentioned as examples.
• Suitable formulations for the receiver layer composition are e.g. B. in EP-A-227 094, EP-A-133 012, EP-A-133 011, EP-A-111 004, JP-A-199 997/1986, JP-A-283 595/1986, JP-A-237 694/1986 or JP-A-127 392/1986 described in detail.
• the transfer takes place by means of a thermal head, which must be able to be heated to a temperature of C 300 ° C. so that the dye transfer can take place in the time range t: 0 ⁇ t ⁇ 15 msec.
• the dye migrates from the transfer sheet and diffuses into the surface coating of the recording medium.
• the thermal transfer was carried out with large-area heating jaws instead of a thermal head, the transfer temperature varying in the range from 70 ° C ⁇ T ⁇ 120 ° C and the transfer time being set at 2 minutes.
• the polyester film (donor) containing the dye to be tested in the coating composition front side was placed with the front side on commercially available Hitachi Color Video Print Paper (receiver) and pressed on.
• the encoder / receiver was then wrapped with aluminum foil and heated between two heated plates at different temperatures T (in the temperature interval 70 ° C ⁇ T ⁇ 120 ° C).
• the dyes mentioned in the following tables were processed according to A) and the resulting dye-coated supports were tested for transfer behavior according to B).
• the table shows the thermal transfer parameters T * and ⁇ E T , the absorption maxima of the dyes ⁇ max (measured in methylene chloride), the binders used and the auxiliaries.
• the dyes of the formula listed in Table 5 below can be used in an analogous manner be transmitted.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Printing Methods (AREA)
• Coloring (AREA)
• Plural Heterocyclic Compounds (AREA)

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Citations (4)

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• 1988
  • 1988-05-31 DE DE3818404A patent/DE3818404A1/de not_active Withdrawn
• 1989
  • 1989-05-24 EP EP89109327A patent/EP0344592B2/fr not_active Expired - Lifetime
  • 1989-05-24 DE DE89109327T patent/DE58905420D1/de not_active Expired - Lifetime
  • 1989-05-30 JP JP1134837A patent/JP2746656B2/ja not_active Expired - Lifetime
  • 1989-05-30 US US07/358,142 patent/US5037798A/en not_active Expired - Fee Related

Patent Citations (4)

Non-Patent Citations (2)

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