EP0460463A1 - Use of azo dyes in thermal transfer printing - Google Patents

Use of azo dyes in thermal transfer printing Download PDF

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EP0460463A1
EP0460463A1 EP91108420A EP91108420A EP0460463A1 EP 0460463 A1 EP0460463 A1 EP 0460463A1 EP 91108420 A EP91108420 A EP 91108420A EP 91108420 A EP91108420 A EP 91108420A EP 0460463 A1 EP0460463 A1 EP 0460463A1
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Prior art keywords
alkyl
ethyl
azo dyes
substituents
alkoxy
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German (de)
French (fr)
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EP0460463B1 (en
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Ruediger Sens
Helmut Reichelt
Sabine Gruettner
Karl-Heinz Etzbach
Gunther Lamm
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BASF SE
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BASF SE
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    • 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 main heat source used is a thermal head with which short heating impulses lasting a fraction of a second can be emitted.
  • a transfer sheet which contains the dye to be transferred together with one or more binders, a carrier material and possibly other auxiliaries such as release agents or crystallization-inhibiting substances is heated from the rear by the thermal head.
  • the dye diffuses from the transfer sheet into the surface coating of the substrate, e.g. into the plastic layer of a coated paper.
  • the main advantage of this method is that the amount of color transferred and thus the color gradation can be specifically controlled via the energy to be delivered to the thermal head.
  • Thermal transfer printing generally uses the three subtractive primary colors yellow, magenta and cyan, possibly also black, whereby the dyes used for optimum color recording must have the following properties: easy thermal transferability, low tendency to migrate within or from the surface coating of the recording medium at room temperature , high thermal and photochemical stability as well as resistance to moisture and chemicals, no tendency to crystallize when storing the transfer sheet, a suitable color for the subtractive color mixture, a high molar absorption coefficient and easy technical accessibility.
  • the azo dyes I themselves are known from the earlier German patent applications P 38 10 643.4 and P 38 16 698.4 or can be obtained by the methods mentioned there.
  • the invention was therefore based on the object, suitable for thermal transfer printing red and To find yellow dyes that come closer to the required property profile than the previously known dyes.
  • a method for transferring azo dyes by diffusion from a support onto a plastic-coated substrate using a thermal head was found, which is characterized in that a support is used for this purpose, on which one or more of the azo dyes I defined at the outset are located.
  • Suitable alkyl radicals R 1 or R 2 are especially methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl.
  • Alkyl radicals R 1 can also be pentyl, isopentyl, neopentyl, tert-pentyl, hexyl and 2-methylpentyl.
  • alkoxy radicals R 2 are methoxy, ethoxy, propoxy, isopropoxy, butoxy and isobutoxy.
  • radical R 1 is a phenyl group bearing substituents, the following may be mentioned, for example: methyl, ethyl, methoxy, ethoxy, chlorine, bromine and cyanophenyl, the substituents of which are each in the 2, 3 or 4 position to sit.
  • Suitable alkyl radicals R 3, R 3 ' , R 4, R 4 ', R S , R 6 , R 7 or R 8 are especially methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert.- Butyl.
  • Alkyl radicals R 3 , R 3 ', R 4 , R 4 ', R 7 or R 8 are also, for example, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl and 2-ethylhexyl, R 3 , R 3 ', R 4 or R 4 ' additionally, for example, nonyl and decyl.
  • the C chain of the alkyl radicals R 3 , R 3 ', R 4 ' or R 4 ' is interrupted by one to three oxygen atoms
  • the following groups may be mentioned, for example: 2-methoxy, 2-ethoxy, 2-propoxy , 2-butoxyethyl, 2- and 3-methoxypropyl, 1-methoxyprop-2-yl, 2-ethoxypropyl, 2-propoxypropyl, 4,7-dioxaoctyl, 4,7-dioxanonyl, 4,8-dioxadecyl, 4,7, 10-trioxaundecyl and 4,7,10-trioxadodecyl.
  • Suitable alkoxy radicals R 5 or R 6 are, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy and isobutoxy.
  • Preferred azo dyes I can be found in the examples.
  • the dyes I to be used according to the invention are distinguished from the red and yellow dyes previously used for thermal transfer printing by the following properties: easier thermal transferability despite the relatively high molecular weight, improved migration properties in the recording medium at room temperature, significantly higher lightfastness, better resistance to moisture and chemicals , better solubility in the production of the printing ink, higher color strength and easier technical accessibility.
  • the azo dyes show a significantly better color purity, especially in dye mixtures, and result in improved black prints.
  • the transfer sheets required as dye donors for the thermal transfer printing process according to the invention are prepared as follows:
  • the azo dyes I are dissolved in an organic solvent, e.g. Isobutanol, methyl ethyl ketone, methylene chloride, chlorobenzene, toluene, tetrahydrofuran or mixtures thereof, processed with one or more binders and possibly other auxiliaries such as release agents or crystallization inhibitors to give a printing ink which preferably contains the dyes in molecularly dispersed solution.
  • the printing ink is then applied to an inert support and dried.
  • Suitable binders for the use according to the invention of the azo dyes I are all materials which are soluble in organic solvents and are known to serve for thermal transfer printing, for example cellulose derivatives such as methyl cellulose, hydroxypropyl cellulose, cellulose acetate or cellulose acetobutyrate, especially ethyl cellulose and ethyl hydroxyethyl cellulose, starch, alginates, alkynyl alcohol and alkyd alcohol or polyvinylpyrrolidone and especially polyvinyl acetate and polyvinyl butyrate.
  • cellulose derivatives such as methyl cellulose, hydroxypropyl cellulose, cellulose acetate or cellulose acetobutyrate, especially ethyl cellulose and ethyl hydroxyethyl cellulose, starch, alginates, alkynyl alcohol and alkyd alcohol or polyvinylpyrrolidone and especially polyvinyl acetate and polyvinyl butyrate.
  • 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 resins such as gum arabic.
  • binders are often recommended, e.g. those made of ethyl cellulose and polyvinyl butyrate in a weight ratio of 2: 1.
  • the weight ratio of binder to dye is usually 8: 1 to 1: 1, preferably 5: 1 to 2: 1.
  • Inert carrier materials are, for example, tissue paper, blotting paper or glassine paper and films made of heat-resistant plastics such as polyesters, polyamides or polyimides, these films also being able to be metal-coated.
  • the inert carrier can also be coated with a lubricant on the side facing the thermal head in order to prevent the thermal head from sticking to the carrier material.
  • Suitable lubricants are, for example, silicones or polyurethanes, as are described in EP-A-216 483.
  • the thickness of the dye carrier is generally 3 to 30 microns, preferably 5 to 10 microns.
  • the substrate to be printed e.g. Paper
  • a binder that absorbs the dye during the printing process.
  • Polymeric materials whose glass transition temperature Tg is between 50 and 100 ° C., i.e. e.g. Polycarbonates and polyester. Further details can be found in EP-A-227 094, EP-A-133 012, EP-A-133 011, JP-A-199 997/1986 or JP-A 283 595/1986.
  • a thermal head which can be heated to temperatures above 300 ° C., so that the dye transfer takes place in a maximum of 15 msec.
  • transfer sheets were produced in a conventional manner from 8 ⁇ m thick polyester film, which was provided with an approx. 5 ⁇ m thick transfer layer made from a binder B, each of which contained 0.25 g of azo dye I.
  • the weight ratio of binder to dye was 4: 1 in each case.
  • the substrate to be printed consisted of paper approximately 120 ⁇ m thick, which was coated with an 8 ⁇ m thick plastic layer (Hitachi Color Video Print Paper).
  • the coated side of the encoder and slave was placed on top of one another, wrapped with aluminum foil and heated to a temperature between 70 and 80 C for two minutes between two heating plates. With similar samples, this process was repeated three times at a higher temperature between 80 and 120 ° C.
  • the amount of dye diffused into the plastic layer of the receiver is proportional to the optical density, which was determined as absorbance A photometrically after the respective heating to the temperatures given above.
  • the temperature T * at which the absorbance reaches the value 2 can also be taken from the application, ie the transmitted light intensity is one hundredth of the incident light intensity.
  • the smaller the temperature T * the better the thermal transferability of the investigated dye.
  • Tables 1a to 9a list the azo dyes I tested for their thermal transfer behavior and their color.

Abstract

Use of azo dyes I <IMAGE> for thermal transfer printing, in which the substituents have the following meaning:   X is a radical IIa or IIb <IMAGE>   where R<1> is H; C1-C6-alkyl or phenyl which can carry C1-C4-alkyl, C1-C2-alkoxy, chlorine, bromine or cyano as substituents;   R<2> is H; C1-C4-alkyl, C1-C4-alkoxy, chlorine or bromine; n is 1 or 2; K is the radical of a coupling component II H-K III from the aniline, aminonaphthaline, pyrazole, diaminopyridine, hydroxypyridone or tetrahydroquinoline series.

Description

Die vorliegende Erfindung betrifft die Verwendung von Azofarbstoffen.der allgemeinen Formel I

Figure imgb0001

  • für den Thermotransferdruck, in der die Substituenten folgende Bedeutung haben: X einen Rest der Formel Ila oder Ilb
    Figure imgb0002
    wobei
  • R1 Wasserstoff, eine C1-C6-Alkylgruppe oder eine Phenylgruppe, die Ci-C4--Alkyl, C1-C2-Alkoxy, Chlor, Brom oder Cyano als Substituenten tragen kann, bedeutet,
  • n für 1 oder 2 steht und
  • R2 Wasserstoff, Ci-C4-Alkyl, Ci-C4.-Alkoxy, Chlor oder Brom bezeichnet;
  • K den Rest einer Kupplungskomponente III
    Figure imgb0003
    aus der Anilin-, Aminonaphthalin-, Pyrazol-, Diaminopyridin-, Hydroxypyridon- oder Tetrahydrochinolinreihe

sowie ein Verfahren zur Übertragung dieser Azofarbstoffe durch Diffusion von einem Träger auf ein mit Kunststoff beschichtetes Substrat mit Hilfe eines Thermokopfes.The present invention relates to the use of azo dyes of the general formula I.
Figure imgb0001
  • for thermal transfer printing, in which the substituents have the following meaning: X is a radical of the formula Ila or Ilb
    Figure imgb0002
     in which
  • R 1 is hydrogen, a C 1 -C 6 alkyl group or a phenyl group which can carry C 1 -C 4 alkyl, C 1 -C 2 alkoxy, chlorine, bromine or cyano as substituents,
  • n stands for 1 or 2 and
  • R 2 denotes hydrogen, C i -C 4 alkyl, C i -C 4 alkoxy, chlorine or bromine;
  • K the rest of a coupling component III
    Figure imgb0003
     from the aniline, aminonaphthalene, pyrazole, diaminopyridine, hydroxypyridone or tetrahydroquinoline series

and a method for transferring these azo dyes by diffusion from a support to a plastic-coated substrate using a thermal head.

Die Technik des Thermotransferdrucks ist allgemein bekannt; als Wärmequelle kommt neben Laser und IR-Lampe vor allem ein Thermokopf zur Anwendung, mit dem kurze Heizimpulse der Dauer von Bruchteilen einer Sekunde abgegeben werden können.The technique of thermal transfer printing is well known; In addition to the laser and IR lamp, the main heat source used is a thermal head with which short heating impulses lasting a fraction of a second can be emitted.

Bei dieser bevorzugten Ausführungsform des Thermotransferdrucks wird ein Transferblatt, das den zu übertragenden Farbstoff zusammen mit einem oder mehreren Bindemitteln, einem Trägermaterial und eventuell weiteren Hilfsmitteln wie Trennmitteln oder kristallisationshemmenden Stoffen enthält, von der Rückseite her durch den Thermokopf erhitzt. Dabei diffundiert der Farbstoff aus dem Transferblatt in die Oberflächenbeschichtung des Substrates, z.B. in die Kunststoffschicht eines beschichteten Papiers.In this preferred embodiment of thermal transfer printing, a transfer sheet which contains the dye to be transferred together with one or more binders, a carrier material and possibly other auxiliaries such as release agents or crystallization-inhibiting substances is heated from the rear by the thermal head. The dye diffuses from the transfer sheet into the surface coating of the substrate, e.g. into the plastic layer of a coated paper.

Der wesentliche Vorteil dieses Verfahrens besteht darin, daß über die an den Thermokopf abzugebende Energie die übertragene Farbmenge und damit die Farbabstufung gezielt gesteuert werden kann.The main advantage of this method is that the amount of color transferred and thus the color gradation can be specifically controlled via the energy to be delivered to the thermal head.

Beim Thermotransferdruck werden allgemein die drei subtraktiven Grundfarben Gelb, Magenta und Cyan, gegebenenfalls zusätzlich Schwarz, verwendet, wobei die eingesetzten Farbstoffe für eine optimale Farbaufzeichnung folgende Eigenschaften aufweisen müssen: leichte thermische Transferierbarkeit, geringe Neigung zur Migration innerhalb oder aus der Oberflächenbeschichtung des Aufnahmemediums bei Raumtemperatur, hohe thermische und photochemische Stabilität sowie Resistenz gegen Feuchtigkeit und Chemikalien, keine Tendenz zur Kristallisation bei Lagerung des Transferblattes, einen geeigneten Farbton für die subtraktive Farbmischung, einen hohen molaren Absorptionskoeffizienten und leichte technische Zugänglichkeit.Thermal transfer printing generally uses the three subtractive primary colors yellow, magenta and cyan, possibly also black, whereby the dyes used for optimum color recording must have the following properties: easy thermal transferability, low tendency to migrate within or from the surface coating of the recording medium at room temperature , high thermal and photochemical stability as well as resistance to moisture and chemicals, no tendency to crystallize when storing the transfer sheet, a suitable color for the subtractive color mixture, a high molar absorption coefficient and easy technical accessibility.

Diese Anforderungen sind gleichzeitig nur sehr schwer zu erfüllen. Daher entsprechen die meisten der für den Thermotransferdruck vorgeschlagenen Farbstoffe nicht dem geforderten Eigenschaftsprofil. Dies gilt beispielsweise auch für die in der US-A-4 764 178 beschriebenen und für den Thermotransferdruck empfohlenen Azofarbstoffe, die Kupplungskomponenten aus der Anilin-, Tetrahydrochinolin-, Aminochinolin-oder Julolidinreihe aufweisen, sowie für die aus den EP-A-258 856 und US-A-4 698 651 für dieselbe Verwendung bekannten Azofarbstoffe mit Kupplungskomponenten auf Anilinbasis, die sich u.a. alle durch die Art des zum Stickstoffatom im Thiazolring orthoständigen Substituenten von den Azofarbstoffen I unterscheiden.At the same time, these requirements are very difficult to meet. Therefore, most of the dyes proposed for thermal transfer printing do not meet the required property profile. This also applies, for example, to the azo dyes described in US Pat. No. 4,764,178 and recommended for thermal transfer printing, which have coupling components from the aniline, tetrahydroquinoline, aminoquinoline or julolidine series, and to EP-A-258 856 and US-A-4 698 651 for the same use known azo dyes with coupling components based on aniline, which are among others all differ from the azo dyes I by the nature of the substituent ortho to the nitrogen atom in the thiazole ring.

Die Azofarbstoffe I selbst sind aus den älteren deutschen Patentanmeldungen P 38 10 643.4 und P 38 16 698.4 bekannt oder können nach den dort genannten Methoden erhalten werden.The azo dyes I themselves are known from the earlier German patent applications P 38 10 643.4 and P 38 16 698.4 or can be obtained by the methods mentioned there.

Der Erfindung lag daher die Aufgabe zugrunde, für den Thermotransferdruck geeignete Rot- und Gelbfarbstoffe zu finden, die dem geforderten Eigenschaftsprofil näherkommen als die bisher bekannten Farbstoffe.The invention was therefore based on the object, suitable for thermal transfer printing red and To find yellow dyes that come closer to the required property profile than the previously known dyes.

Demgemäß wurde die Verwendung der eingangs definierten Azofarbstoffe I für den Thermotransferdruck gefunden.Accordingly, the use of the azo dyes I defined at the outset was found for thermal transfer printing.

Außerdem wurde ein Verfahren zur Übertragung von Azofarbstoffen durch Diffusion von einem Träger auf ein mit Kunststoff beschichtetes Substrat mit Hilfe eines Thermokopfes gefunden, welches dadurch gekennzeichnet ist, daß man hierfür einen Träger verwendet, auf dem sich ein oder mehrere der eingangs definierten Azofarbstoffe I befinden.In addition, a method for transferring azo dyes by diffusion from a support onto a plastic-coated substrate using a thermal head was found, which is characterized in that a support is used for this purpose, on which one or more of the azo dyes I defined at the outset are located.

Geeignete Alkylreste R1 oder R2 sind dabei vor allem Methyl, Ethyl, Propyl, Isopropyl, Butyl, Isobutyl, sec.-Butyl und tert.-Butyl. Alkylreste R1 können weiterhin auch Pentyl, Isopentyl, Neopentyl, tert.-Pentyl, Hexyl und 2-Methylpentyl sein.Suitable alkyl radicals R 1 or R 2 are especially methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl. Alkyl radicals R 1 can also be pentyl, isopentyl, neopentyl, tert-pentyl, hexyl and 2-methylpentyl.

Als Alkoxyrest R2 eignen sich z.B. Methoxy, Ethoxy, Propoxy, Isopropoxy, Butoxy und Isobutoxy.Examples of suitable alkoxy radicals R 2 are methoxy, ethoxy, propoxy, isopropoxy, butoxy and isobutoxy.

Handelt es sich bei dem Rest R1 um eine Substituenten tragende Phenylgruppe, so sind beispielsweise zu nennen: Methyl-, Ethyl-, Methoxy-, Ethoxy-, Chlor-, Brom- und Cyanophenyl, deren Substituenten jeweils in Stellung 2, 3 oder 4 sitzen.If the radical R 1 is a phenyl group bearing substituents, the following may be mentioned, for example: methyl, ethyl, methoxy, ethoxy, chlorine, bromine and cyanophenyl, the substituents of which are each in the 2, 3 or 4 position to sit.

Bevorzugte Reste X der Formel Ila oder IIb sind z.B.:

  • Methoxy-, Ethoxy-, Propoxy-, Butoxymethyl,
  • 2-Methoxy-, 2-Ethoxy-, 2-Propoxy-, 2-Butoxy-, 2-Pentyloxy- und 2-Hexyloxyethyl;
  • 2-, 3- und 4-Pyridyl.
Preferred radicals X of the formula Ila or IIb are, for example:
  • Methoxy, ethoxy, propoxy, butoxymethyl,
  • 2-methoxy, 2-ethoxy, 2-propoxy, 2-butoxy, 2-pentyloxy and 2-hexyloxyethyl;
  • 2-, 3- and 4-pyridyl.

Bevorzugte Kupplungskomponenten III sind:

  • - Anilinderivate der allgemeinen Formel Illa
    Figure imgb0004
  • - Aminonaphthalinderivate der allgemeinen Formel IIlb
    Figure imgb0005
  • - Pyrazolderivate der allgemeinen Formel IIIc
    Figure imgb0006
  • - Diaminopyridinderivate der allgemeinen Formel IIId
    Figure imgb0007
  • - Hydroxypyridonderivate der allgemeinen Forml Ille
    Figure imgb0008
  • - Tetrahydrochinolinderivate der allgemeinen Formel Illf
    Figure imgb0009
Preferred coupling components III are:
  • - Aniline derivatives of the general formula Illa
    Figure imgb0004
  • - Aminonaphthalene derivatives of the general formula IIlb
    Figure imgb0005
  • - Pyrazole derivatives of the general formula IIIc
    Figure imgb0006
  • - Diaminopyridine derivatives of the general formula IIId
    Figure imgb0007
  • - Hydroxypyridone derivatives of the general formula II
    Figure imgb0008
  • - Tetrahydroquinoline derivatives of the general formula Illf
    Figure imgb0009

Dabei haben die Substituenten folgende Bedeutung:

  • R3, R3', R 4, R4-' Wasserstoff; C1-C10-Alkyl, deren C-Kette durch ein bis drei Sauerstoffatome in Etherfunktion unterbrochen sein kann und die folgende Substituenten tragen können: Cyano, Hydroxy, Phenyl, Phenoxy, Phenylaminocarbonyloxy, Benzyloxy, Benzoyloxy, das C1-C4-Alkyl, C1-C4-Alkoxy, Fluor, Chlor oder Brom als Substituenten tragen kann, C1-C4-Alkanoyloxy, Ci-C6-Alkoxycarbonyloxy, C1-C8-Alkoxycarbonyl, Mono- oder Di-C1-Cs-alkylaminocarbonyloxy, wobei die C-Kette der drei letztgenannten Substituenten jeweils durch ein oder zwei Sauerstoffatome in Etherfunktion unterbrochen sein kann; C3-C5-Alkenyl oder C5-C7-Cycloalkyl; Phenyl, das C1-C4-Alkyl, C1-C4-Alkoxy, Cl-C4-Dialkylamino, Acetylamino, Fluor, Chlor oder Brom als Substituenten tragen kann;
  • R 5 Wasserstoff, Chlor; C1-C4-Alkyl, C1-C4-Alkoxy, C1-C4-Alkanoylamino, das C1-C4-Alkoxy, Phenoxy oder Chlor als Substituenten tragen kann, C2-C3-Alkenoylamino, Benzoylamino, Ureido, Mono- oder Di-C1-C4-alkylureido oder C1-C4-Alkylsulfonylamino;
  • R6 Wasserstoff, Chlor, C1-C4-Alkyl oder C1-C4-Alkoxy;
  • R7 Wasserstoff, C1-C8-Alkyl oder Phenyl;
  • R8 Wasserstoff, C1-C8-Alkyl, das Phenyl, Furyl oder Thienyl als Substituenten tragen kann, C5-C7-Cycloalkyl oder Phenyl.
The substituents have the following meaning:
  • R3 , R 3 ' , R 4 , R4-'hydrogen; C 1 -C 10 alkyl, the C chain of which can be interrupted by one to three oxygen atoms in ether function and can carry the following substituents: cyano, hydroxy, phenyl, phenoxy, phenylaminocarbonyloxy, benzyloxy, benzoyloxy, the C 1 -C 4 - may carry alkyl, C 1 -C 4 -alkoxy, fluorine, chlorine or bromine, C 1 -C 4 alkanoyloxy, C i -C 6 alkoxycarbonyloxy, C 1 -C 8 alkoxycarbonyl, mono- or di-C 1 -C s -alkylaminocarbonyloxy, where the C chain of the three latter substituents can each be interrupted by one or two oxygen atoms in ether function; C 3 -C 5 alkenyl or C 5 -C 7 cycloalkyl; Phenyl which can carry C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 dialkylamino, acetylamino, fluorine, chlorine or bromine as substituents;
  • R 5 is hydrogen, chlorine; C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkanoylamino, which can carry C 1 -C 4 alkoxy, phenoxy or chlorine as substituents, C2-C 3 -alkenoylamino, benzoylamino, Ureido, mono- or di-C 1 -C 4 alkylureido or C 1 -C 4 alkylsulfonylamino;
  • R 6 is hydrogen, chlorine, C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
  • R 7 is hydrogen, C 1 -C 8 alkyl or phenyl;
  • R 8 is hydrogen, C 1 -C 8 alkyl which may carry phenyl, furyl or thienyl as substituents, C 5 -C 7 cycloalkyl or phenyl.

Geeignete Alkylreste R3, R3', R4, R 4', R S, R6, R7 oder R8 sind vor allem Methyl, Ethyl, Propyl, Isopropyl, Butyl, Isobutyl, sec.-Butyl und tert.-Butyl.Suitable alkyl radicals R 3, R 3 ' , R 4, R 4 ', R S , R 6 , R 7 or R 8 are especially methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert.- Butyl.

Alkylreste R3, R3', R4, R4', R7 oder R8 sind weiterhin z.B. Pentyl, Isopentyl, Neopentyl, tert.-Pentyl, Hexyl, 2-Methylpentyl, Heptyl, Octyl und 2-Ethylhexyl, R3, R3', R4 oder R4' zusätzlich z.B. Nonyl und Decyl.Alkyl radicals R 3 , R 3 ', R 4 , R 4 ', R 7 or R 8 are also, for example, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl and 2-ethylhexyl, R 3 , R 3 ', R 4 or R 4 ' additionally, for example, nonyl and decyl.

Ist die C-Kette der Alkylreste R3, R3', R4' oder R4' durch ein bis drei Sauerstoffatome unterbrochen, so sind beispielsweise folgende Gruppen zu nennen: 2-Methoxy-, 2-Ethoxy-, 2-Propoxy-, 2-Butoxyethyl, 2- und 3-Methoxypropyl, 1-Methoxyprop-2-yl, 2-Ethoxypropyl, 2-Propoxypropyl, 4,7-Dioxaoctyl, 4,7-Dioxanonyl, 4,8-Dioxadecyl, 4,7,10-Trioxaundecyl und 4,7,10-Trioxadodecyl.If the C chain of the alkyl radicals R 3 , R 3 ', R 4 ' or R 4 'is interrupted by one to three oxygen atoms, the following groups may be mentioned, for example: 2-methoxy, 2-ethoxy, 2-propoxy , 2-butoxyethyl, 2- and 3-methoxypropyl, 1-methoxyprop-2-yl, 2-ethoxypropyl, 2-propoxypropyl, 4,7-dioxaoctyl, 4,7-dioxanonyl, 4,8-dioxadecyl, 4,7, 10-trioxaundecyl and 4,7,10-trioxadodecyl.

Alkylreste R3, R3', R4 oder R4' können zusätzlich als Substituenten Cyano und Hydroxy tragen; als Beispiele sind hier zu nennen:

  • Cyanomethyl, 2-Cyanoethyl und 3-Cyanopropyl; 2-Hydroxyethyl, 2-Hydroxypropyl, 1-Hydroxyprop-2-yl, 2-Hydroxybutyl, 1-Hydroxybut-2-yl, 4-Hydroxybutyl und 8-Hydroxy-4-oxaoctyl.
Alkyl radicals R 3 , R 3 ', R 4 or R 4 ' can additionally carry cyano and hydroxy as substituents; examples are:
  • Cyanomethyl, 2-cyanoethyl and 3-cyanopropyl; 2-hydroxyethyl, 2-hydroxypropyl, 1-hydroxyprop-2-yl, 2-hydroxybutyl, 1-hydroxybut-2-yl, 4-hydroxybutyl and 8-hydroxy-4-oxaoctyl.

Weiterhin geeignete Alkylreste R3, R3', R4 oder R4' weisen Phenyl, Phenoxy, Phenylaminocarbonyloxy sowie Benzyloxy oder Benzoyloxy als Substituenten auf, z.B.:

  • Benzyl, 1-Phenylethyl und 2-Phenylethyl, 2-Phenoxy-ethyl, 6-Phenoxy-4-oxahexyl und 2-(Phenylaminocarbonyloxy)ethyl;
  • 3-Benzyloxypropyl und 2-Benzoyloxyethyl, 2-(2-Methylbenzoyloxy)-ethyl, 2-(4-Methylbenzoyloxy)ethyl, 2-(4-Chlorbenzoyloxy)ethyl, 2-(4-Methoxybenzoyloxy)ethyl, 2-Benzoyloxypropyl und 2-Benzyloxybutyl.
Suitable alkyl radicals R 3 , R 3 ', R 4 or R 4 ' have phenyl, phenoxy, phenylaminocarbonyloxy and benzyloxy or benzoyloxy as substituents, for example:
  • Benzyl, 1-phenylethyl and 2-phenylethyl, 2-phenoxy-ethyl, 6-phenoxy-4-oxahexyl and 2- (phenylaminocarbonyloxy) ethyl;
  • 3-benzyloxypropyl and 2-benzoyloxyethyl, 2- (2-methylbenzoyloxy) ethyl, 2- (4-methylbenzoyloxy) ethyl, 2- (4-chlorobenzoyloxy) ethyl, 2- (4-methoxybenzoyloxy) ethyl, 2-benzoyloxypropyl and 2 -Benzyloxybutyl.

Tragen die Alkylreste R3, R3', R4 oder R4' Alkanoyloxy, Alkoxycarbonyloxy, Alkoxycarbonyl oder Alkylaminocarbonyloxy als Substituenten, so kommen beispielsweise folgende Gruppen in Betracht: 2-Acetyloxy-, 2-Propionyloxy-, 2-Pentanoyloxyethyl,

  • 2-Acetyloxy-, 3-Acetyloxy-, 2-Propionyloxypropyl, 2-Acetyloxy-, 4-Acetyloxy-, 2-Propionyloxybutyl und 8-Acetyloxy-4-oxaoctyl; 2-(Ethoxycarbonyloxy)ethyl, 2-(Butoxycarbonyloxy)ethyl und 4-(Ethoxycarbonyloxy)butyl; Methoxycarbonyl-, Ethoxycarbonyl-, Propoxycarbonyl-, Butoxycarbonylmethyl, 1-(Methoxycarbonyl)-, 2-(Methoxycarbonyl)-, 2-(Ethoxycarbonyl)-, 2-(Propoxycarbonyl)-, 2-(Butoxycarbonyl)-, 2-(lsobutoxycarbonyl)-, 2-(2-Ethylhexyloxycarbonyl)ethyl, 2-(3-Oxabutyloxycarbonyl)-, 2-(3-Oxapentyloxycarbonyl)- und 2-(3-Oxaheptyloxycarbonyl)ethyl; 2-(Diethylaminocarbonyloxy)ethyl.
If the alkyl radicals R 3 , R 3 ', R4 or R 4 ' carry alkanoyloxy, alkoxycarbonyloxy, alkoxycarbonyl or alkylaminocarbonyloxy as substituents, the following groups are suitable, for example: 2-acetyloxy-, 2-propionyloxy-, 2-pentanoyloxyethyl,
  • 2-acetyloxy, 3-acetyloxy, 2-propionyloxypropyl, 2-acetyloxy, 4-acetyloxy, 2-propionyloxybutyl and 8-acetyloxy-4-oxaoctyl; 2- (ethoxycarbonyloxy) ethyl, 2- (butoxycarbonyloxy) ethyl and 4- (ethoxycarbonyloxy) butyl; Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonylmethyl, 1- (methoxycarbonyl) -, 2- (methoxycarbonyl) -, 2- (ethoxycarbonyl) -, 2- (propoxycarbonyl) -, 2- (butoxycarbonyl) -, 2- (isobutoxycarbonyl ) -, 2- (2-ethylhexyloxycarbonyl) ethyl, 2- (3-oxabutyloxycarbonyl) -, 2- (3-oxapentyloxycarbonyl) - and 2- (3-oxaheptyloxycarbonyl) ethyl; 2- (diethylaminocarbonyloxy) ethyl.

Handelt es sich bei den Resten R3, R3', R4 oder R4' um Alkenyl-, Cycloalkyl- oder Substituenten tragende Phenylgruppen, so sind z.B. zu nennen:

  • Allyl und Methallyl; Cyclopentyl, Cyclohexyl, Methylcyclohexyl und Cycloheptyl; 2-,3- und 4-Methylphenyl, 2- und 4-Methoxyphenyl, 2- und 4-Ethoxyphenyl, 4-Dimethylaminophenyl, 4-Acetylaminophenyl, 5-Chlorphenyl und 2,4-Dichlorphenyl.
If the radicals R 3 , R 3 ', R 4 or R 4 ' are phenyl groups bearing alkenyl, cycloalkyl or substituents, the following may be mentioned, for example:
  • Allyl and methallyl; Cyclopentyl, cyclohexyl, methylcyclohexyl and cycloheptyl; 2-, 3- and 4-methylphenyl, 2- and 4-methoxyphenyl, 2- and 4-ethoxyphenyl, 4-dimethylaminophenyl, 4-acetylaminophenyl, 5-chlorophenyl and 2,4-dichlorophenyl.

Geeignete Alkoxyreste R5 oder R6 sind beispielsweise Methoxy, Ethoxy, Propoxy, Isopropoxy, Butoxy und Isobutoxy.Suitable alkoxy radicals R 5 or R 6 are, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy and isobutoxy.

Als Rest R5 eignen sich weiterhin Alkanoylamino, Alkenoylamino, Benzoylamino, Alkylureido oder Alkylsulfonylamino wie:

  • Acetylamino, Propionylamino, Methoxy-, Ethoxy-, Chlor- und Phenoxy-acetylamino; Acryloylamino und Methacryloylamino; N-Methylureido, N-Butylureido und N,N-Dimethylureido; Methylsulfonylamino, Ethylsulfonylamino, Propylsulfonylamino und Butylsulfonylamino.
As R 5 continues alkanoylamino, alkenoylamino, benzoylamino, alkylureido or alkylsulfonylamino suitable as:
  • Acetylamino, propionylamino, methoxy, ethoxy, chloro and phenoxy acetylamino; Acryloylamino and methacryloylamino; N-methylureido, N-butylureido and N, N-dimethylureido; Methylsulfonylamino, ethylsulfonylamino, propylsulfonylamino and butylsulfonylamino.

Der Rest R8 kann z.B. auch folgendermaßen substituiertes Alkyl sein:

  • Benzyl, 1- und 2-Phenylethyl, Fur-2-ylmethyl, 2-(Fur-2-yl)ethyl, 2-(Thien-2-yl)ethyl und 2-(Pyrid-2-yl)ethyl.
The radical R 8 can, for example, also be alkyl substituted as follows:
  • Benzyl, 1- and 2-phenylethyl, fur-2-ylmethyl, 2- (fur-2-yl) ethyl, 2- (thien-2-yl) ethyl and 2- (pyrid-2-yl) ethyl.

Von den oben aufgeführten Kupplungskomponenten H-K sind diejenigen der Formeln lila, lllc, IIld, llle und Illf besonders bevorzugt.Of the coupling components H-K listed above, those of the formulas lilac, lllc, llld, llle and illf are particularly preferred.

Ganz besonders bevorzugte Kupplungskomponenten sind Anilinderivate IIIa und Tetrahydrochinolinderivate Illf mit folgender Bedeutung der Substituenten:

  • R3, R4 Wasserstoff; C1-Ca-Alkyl, deren C-Kette durch ein Sauerstoffatom unterbrochen sein kann und die Cyano, Hydroxy, C1-C4-Alkanoyloxy oder C1-C8-Alkoxycarbonyl als Substituenten tragen können; C5-C7-Cycloalkyl;
  • R5 Wasserstoff, Methyl, Methoxy oder Acetylamino;
  • R 6 Wasserstoff;
  • R7 Methyl.
Very particularly preferred coupling components are aniline derivatives IIIa and tetrahydroquinoline derivatives Illf with the following meaning of the substituents:
  • R 3, R 4 are hydrogen; C 1 -Ca alkyl, the C chain of which can be interrupted by an oxygen atom and which can carry cyano, hydroxy, C 1 -C 4 alkanoyloxy or C 1 -C 8 alkoxycarbonyl as substituents; C 5 -C 7 cycloalkyl;
  • R 5 is hydrogen, methyl, methoxy or acetylamino;
  • R 6 is hydrogen;
  • R 7 methyl.

Bevorzugte Azofarbstoffe I sind den Beispielen zu entnehmen.Preferred azo dyes I can be found in the examples.

Die erfindungsgemäß zu verwendenden Farbstoffe I zeichnen sich gegenüber den bisher für den Thermotransferdruck eingesetzten Rot- und Gelbfarbstoffen durch folgende Eigenschaften aus: leichtere thermische Transferierbarkeit trotz des relativ hohen Molekulargewichts, verbesserte Migrationseigenschaften im Aufnahmemedium bei Raumtemperatur, wesentlich höhere Lichtechtheit, bessere Resistenz gegen Feuchtigkeit und Chemikalien, bessere Löslichkeit bei der Herstellung der Druckfarbe, höhere Farbstärke sowie leichtere technische Zugänglichkeit.The dyes I to be used according to the invention are distinguished from the red and yellow dyes previously used for thermal transfer printing by the following properties: easier thermal transferability despite the relatively high molecular weight, improved migration properties in the recording medium at room temperature, significantly higher lightfastness, better resistance to moisture and chemicals , better solubility in the production of the printing ink, higher color strength and easier technical accessibility.

Zudem zeigen die Azofarbstoffe eine deutlich bessere Farbtonreinheit, insbesondere in Farbstoffmischungen, und ergeben verbesserte Schwarz-Drucke.In addition, the azo dyes show a significantly better color purity, especially in dye mixtures, and result in improved black prints.

Die für das erfindungsgemäße Thermotransferdruckverfahren benötigten, als Farbstoffgeber fungierenden Transferblätter werden folgendermaßen präpariert: Die Azofarbstoffe I werden in einem organischen Lösungsmittel, wie z.B. Isobutanol, Methylethylketon, Methylenchlorid, Chlorbenzol, Toluol, Tetrahydrofuran oder deren Mischungen, mit einem oder mehreren Bindemitteln sowie eventuell weiteren Hilfsmitteln wie Trennmitteln oder kristallisationshemmenden Stoffen zu einer Druckfarbe verarbeitet, welche die Farbstoffe vorzugsweise molekular-dispers gelöst enthält. Die Druckfarbe wird anschließend auf einen inerten Träger aufgetragen und getrocknet.The transfer sheets required as dye donors for the thermal transfer printing process according to the invention are prepared as follows: The azo dyes I are dissolved in an organic solvent, e.g. Isobutanol, methyl ethyl ketone, methylene chloride, chlorobenzene, toluene, tetrahydrofuran or mixtures thereof, processed with one or more binders and possibly other auxiliaries such as release agents or crystallization inhibitors to give a printing ink which preferably contains the dyes in molecularly dispersed solution. The printing ink is then applied to an inert support and dried.

Als Bindemittel für die erfindungsgemäße Verwendung der Azofarbstoffe I eignen sich alle in organischen Lösungsmitteln löslichen Materialien, die bekanntermaßen für den Thermotransferdruck dienen, also z.B. Cellulosederivate wie Methylcellulose, Hydroxypropylcellulose, Celluloseacetat oder Celluloseacetobutyrat, vor allem Ethylcellulose und Ethylhydroxyethylcellulose, Stärke, Alginate, Alkydharze wie Polyvinylalkohol oder Polyvinylpyrrolidon sowie besonders Polyvinylacetat und Polyvinylbutyrat. Daneben kommen Polymere und Copolymere von Acrylaten oder deren Derivaten wie Polyacrylsäure, Polymethylmethacrylat-oder Styrolacrylatcopolymere, Polyesterharze, Polyamidharze, Polyurethanharze oder natürliche Harze wie z.B. Gummi Arabicum in Betracht.Suitable binders for the use according to the invention of the azo dyes I are all materials which are soluble in organic solvents and are known to serve for thermal transfer printing, for example cellulose derivatives such as methyl cellulose, hydroxypropyl cellulose, cellulose acetate or cellulose acetobutyrate, especially ethyl cellulose and ethyl hydroxyethyl cellulose, starch, alginates, alkynyl alcohol and alkyd alcohol or polyvinylpyrrolidone and especially polyvinyl acetate and polyvinyl butyrate. In addition, there are 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 resins such as gum arabic.

Häufig empfehlen sich Mischungen dieser Bindemittel, z.B. solche aus Ethylcellulose und Polyvinylbutyrat im Gewichtsverhältnis 2 : 1.Mixtures of these binders are often recommended, e.g. those made of ethyl cellulose and polyvinyl butyrate in a weight ratio of 2: 1.

Das Gewichtsverhältnis von Bindemittel zu Farbstoff beträgt in der Regel 8 : 1 bis 1 : 1, vorzugsweise 5 : 1 bis 2 : 1.The weight ratio of binder to dye is usually 8: 1 to 1: 1, preferably 5: 1 to 2: 1.

Als Hilfsmittel werden z.B. Trennmittel auf der Basis von perfluorierten Alkylsulfonamidoalkylestern oder Siliconen, wie sie in der EP-A-227 092 bzw. der EP-A-192 435 beschrieben sind, und besonders organische Additive, welche das Auskristallisieren der Transferfarbstoffe bei Lagerung und Erhitzung des Farbbandes verhindern, beispielsweise Cholesterin oder Vanillin, verwendet.As aids, e.g. Release agents based on perfluorinated alkylsulfonamidoalkyl esters or silicones as described in EP-A-227 092 or EP-A-192 435, and especially organic additives which prevent the transfer dyes from crystallizing out when the ribbon is stored and heated, for example cholesterol or vanillin used.

Inerte Trägermaterialien sind beispielsweise Seiden-, Lösch- oder Pergaminpapier sowie Folien aus wärmebeständigen Kunststoffen wie Polyestern, Polyamiden oder Polyimiden, wobei diese Folien auch metallbeschichtet sein können.Inert carrier materials are, for example, tissue paper, blotting paper or glassine paper and films made of heat-resistant plastics such as polyesters, polyamides or polyimides, these films also being able to be metal-coated.

Der inerte Träger kann auf der dem Thermokopf zugewandten Seite zusätzlich mit einem Gleitmittel beschichtet werden, um ein Verkleben des Thermokopfes mit dem Trägermaterial zu verhindern. Geeignete Gleitmittel sind beispielsweise Silicone oder Polyurethane, wie sie in der EP-A-216 483 beschrieben sind.The inert carrier can also be coated with a lubricant on the side facing the thermal head in order to prevent the thermal head from sticking to the carrier material. Suitable lubricants are, for example, silicones or polyurethanes, as are described in EP-A-216 483.

Die Stärke des Farbstoffträgers beträgt im allgemeinen 3 bis 30 µm, bevorzugt 5 bis 10 µm.The thickness of the dye carrier is generally 3 to 30 microns, preferably 5 to 10 microns.

Das zu bedruckende Substrat, z.B. Papier, muß seinerseits mit einem Bindemittel beschichtet sein, welches den Farbstoff beim Druckvorgang aufnimmt. Vorzugsweise verwendet man hierzu polymere Materialien, deren Glasumwandlungstemperatur Tg zwischen 50 und 100° C beträgt, also z.B. Polycarbonate und Polyester. Näheres hierzu ist den EP-A-227 094, EP-A-133 012, EP-A-133 011, JP-A-199 997/1986 oder JP-A 283 595/1986 zu entnehmen.The substrate to be printed, e.g. Paper, in turn, must be coated with a binder that absorbs the dye during the printing process. Polymeric materials whose glass transition temperature Tg is between 50 and 100 ° C., i.e. e.g. Polycarbonates and polyester. Further details can be found in EP-A-227 094, EP-A-133 012, EP-A-133 011, JP-A-199 997/1986 or JP-A 283 595/1986.

Für das erfindungsgemäße Verfahren wird ein Thermokopf eingesetzt, der auf Temperaturen bis über 300° C aufheizbar ist, so daß der Farbstofftransfer in einer Zeit von maximal 15 msec erfolgt.For the process according to the invention, a thermal head is used which can be heated to temperatures above 300 ° C., so that the dye transfer takes place in a maximum of 15 msec.

BeispieleExamples

Es wurden zunächst in üblicher Weise Transferblätter (Geber) aus Polyesterfolie von 8 um Stärke hergestellt, die mit einer ca. 5 um starken Transferschicht aus einem Bindemittel B versehen war, welche jeweils 0,25 g Azofarbstoff I enthielt. Das Gewichtsverhältnis Bindemittel zu Farbstoff betrug jeweils 4 : 1.First, transfer sheets (donors) were produced in a conventional manner from 8 μm thick polyester film, which was provided with an approx. 5 μm thick transfer layer made from a binder B, each of which contained 0.25 g of azo dye I. The weight ratio of binder to dye was 4: 1 in each case.

Das zu bedruckende Substrat (Nehmer) bestand aus Papier von ca. 120 um Stärke, das mit einer 8 um dicken Kunststoffschicht beschichtet war (Hitachi Color Video Print Paper).The substrate to be printed (taker) consisted of paper approximately 120 µm thick, which was coated with an 8 µm thick plastic layer (Hitachi Color Video Print Paper).

Geber und Nehmer wurden mit der beschichteten Seite aufeinander gelegt, mit Aluminiumfolie umwikkelt und für 2 min zwischen zwei Heizplatten auf eine Temperatur zwischen 70 und 80 C erhitzt. Mit gleichartigen Proben wurde dieser Vorgang dreimal bei jeweils höherer Temperatur zwischen 80 und 120 °C wiederholt.The coated side of the encoder and slave was placed on top of one another, wrapped with aluminum foil and heated to a temperature between 70 and 80 C for two minutes between two heating plates. With similar samples, this process was repeated three times at a higher temperature between 80 and 120 ° C.

Die hierbei in die Kunststoffschicht des Nehmers diffundierte Farbstoffmenge ist proportional der optischen Dichte, die als Extinktion A photometrisch nach dem jeweiligen Erhitzen auf die oben angegebenen Temperaturen bestimmt wurde.The amount of dye diffused into the plastic layer of the receiver is proportional to the optical density, which was determined as absorbance A photometrically after the respective heating to the temperatures given above.

Die Auftragung des Logarithmus der gemessenen Extinktionswerte A gegen die zugehörige reziproke absolute Temperatur ergibt Geraden, aus deren Steigung die Aktivierungsenergie ΔET für das Transferexperiment zu berechnen ist:

Figure imgb0010
R: allg. GaskonstantePlotting the logarithm of the measured extinction values A against the associated reciprocal absolute temperature gives straight lines, from the slope of which the activation energy ΔE T for the transfer experiment can be calculated:
Figure imgb0010
 R: general gas constant

Der Auftragung kann zusätzlich die Temperatur T* entnommen werden, bei der die Extinktion den Wert 2 erreicht, d.h., die durchgelassene Lichtintensität ein Hundertstel der eingestrahlten Lichtintensität beträgt. Je kleinere Werte die Temperatur T* annimmt, um so besser ist die thermische Transferierbarkeit des untersuchten Farbstoffs.The temperature T * at which the absorbance reaches the value 2 can also be taken from the application, ie the transmitted light intensity is one hundredth of the incident light intensity. The smaller the temperature T * , the better the thermal transferability of the investigated dye.

In den Tabellen 1a bis 9a sind die bezüglich ihres Thermotransferverhaltens untersuchten Azofarbstoffe I unter Angabe ihres Farbtons aufgeführt.Tables 1a to 9a list the azo dyes I tested for their thermal transfer behavior and their color.

Den zugehörigen Tabellen 1 bis 9b sind das für das jeweilige Experiment verwendete Bindemittel B (dabei bedeutet: EC = Ethylcellulose, PVB = Polyvinylbutyrat, MS = EC:PVB = 2:1, EHEC = Ethylhydroxyethylcellulose, CA = Celluloseacetat) und die bereits erwähnten Parameter T* [°C] und AET -[kcal/mol] zu entnehmen.

Figure imgb0011
Figure imgb0012
Figure imgb0013
Figure imgb0014
Figure imgb0015
Figure imgb0016
Figure imgb0017
Figure imgb0018
Figure imgb0019
Figure imgb0020
Figure imgb0021
Figure imgb0022
Figure imgb0023
Figure imgb0024
Figure imgb0025
Figure imgb0026
Figure imgb0027
Figure imgb0028
Figure imgb0029
Figure imgb0030
Figure imgb0031
Figure imgb0032
Figure imgb0033
 The associated Tables 1 to 9b are the binder B used for the respective experiment (where: EC = ethyl cellulose, PVB = polyvinyl butyrate, MS = EC: PVB = 2: 1, EHEC = ethyl hydroxyethyl cellulose, CA = cellulose acetate) and the parameters already mentioned T * [° C] and AE T - [kcal / mol].
Figure imgb0011
Figure imgb0012
Figure imgb0013
Figure imgb0014
Figure imgb0015
Figure imgb0016
Figure imgb0017
Figure imgb0018
Figure imgb0019
Figure imgb0020
Figure imgb0021
Figure imgb0022
Figure imgb0023
Figure imgb0024
Figure imgb0025
Figure imgb0026
Figure imgb0027
Figure imgb0028
Figure imgb0029
Figure imgb0030
Figure imgb0031
Figure imgb0032
Figure imgb0033

Claims (1)

1. Verwendung von Azofarbstoffen der allgemeinen Formel
Figure imgb0034
 für den Thermotransferdruck, in der die Substituenten folgende Bedeutung haben: X einen Rest der Formel IIa oder Ilb
Figure imgb0035
wobei R1 Wasserstoff, eine C1-C6-Alkylgruppe oder eine Phenylgruppe, die C1-C4-Alkyl, C1-C2-Alkoxy, Chlor, Brom oder Cyano als Substituenten tragen kann, bedeutet, n für 1 oder 2 steht und R2 Wasserstoff, C1-C4-Alkyl, C1-C4-Alkoxy, Chlor oder Brom bezeichnet; K den Rest einer Kupplungskomponente III
Figure imgb0036
aus der Anilin-, Aminonaphthalin-, Pyrazol-, Diaminopyridin-, Hydroxypyridon- oder Tetrahydrochinolinreihe. 2. Verfahren zur Übertragung von Azofarbstoffen durch Diffusion von einem Träger auf ein mit Kunststoff beschichtetes Substrat mit Hilfe eines Thermokopfes, dadurch gekennzeichnet, daß man hierfür einen Träger verwendet, auf dem sich ein oder mehrere Azofarbstoffe der Formel I gemäß Anspruch 1 befinden. 1. Use of azo dyes of the general formula
Figure imgb0034
 for thermal transfer printing, in which the substituents have the following meaning: X is a radical of the formula IIa or IIb
Figure imgb0035
 in which R 1 is hydrogen, a C 1 -C 6 alkyl group or a phenyl group which can carry C 1 -C 4 alkyl, C 1 -C 2 alkoxy, chlorine, bromine or cyano as substituents, n stands for 1 or 2 and R 2 denotes hydrogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, chlorine or bromine; K the rest of a coupling component III
Figure imgb0036
 from the aniline, aminonaphthalene, pyrazole, diaminopyridine, hydroxypyridone or tetrahydroquinoline series. 2. Process for the transfer of azo dyes by diffusion from a carrier onto a plastic-coated substrate with the aid of a thermal head, characterized in that a carrier is used for this purpose, on which there are one or more azo dyes of the formula I according to claim 1.
EP91108420A 1990-06-06 1991-05-24 Use of azo dyes in thermal transfer printing Expired - Lifetime EP0460463B1 (en)

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EP0344487A2 (en) * 1988-05-17 1989-12-06 BASF Aktiengesellschaft Azo dyes of the 5-aminoisothiazole series
EP0346729A2 (en) * 1988-06-15 1989-12-20 BASF Aktiengesellschaft Azo dye transfer process with a pyridine coupling component

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5256624A (en) * 1991-04-18 1993-10-26 Basf Aktiengesellschaft Transfer of methine dyes
EP0544301B1 (en) * 1991-11-28 1997-05-14 Sony Corporation Terminal transfer system, printing paper and ink ribbon for the thermal transfer system
WO1995028287A1 (en) * 1994-04-18 1995-10-26 Zeneca Limited Dye diffusion thermal transfer printing
US5693766A (en) * 1994-04-18 1997-12-02 Zeneca Limited Dye diffusion thermal transfer printing
EP2868702A1 (en) * 2013-10-29 2015-05-06 DyStar Colours Distribution GmbH Disperse dyes, their preparation and their use

Also Published As

Publication number Publication date
DE4018067A1 (en) 1991-12-12
EP0460463B1 (en) 1994-12-14
US5200386A (en) 1993-04-06
JPH04232093A (en) 1992-08-20
DE59103852D1 (en) 1995-01-26

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