EP0273307A2 - Method of transferring cationic dyes in their de-protonated, electrically neutral form - Google Patents

Method of transferring cationic dyes in their de-protonated, electrically neutral form Download PDF

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Publication number
EP0273307A2
EP0273307A2 EP87118714A EP87118714A EP0273307A2 EP 0273307 A2 EP0273307 A2 EP 0273307A2 EP 87118714 A EP87118714 A EP 87118714A EP 87118714 A EP87118714 A EP 87118714A EP 0273307 A2 EP0273307 A2 EP 0273307A2
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EP
European Patent Office
Prior art keywords
alkoxy
alkyl
halogen
hydrogen
dyes
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EP87118714A
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German (de)
French (fr)
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EP0273307B1 (en
EP0273307A3 (en
Inventor
Johannes Peter Dr. Dix
Karl-Heinz Dr. Etzbach
Udo Dr. Mayer
Ruediger Dr. Sens
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BASF SE
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BASF SE
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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
    • 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
    • B41M5/3854—Dyes containing one or more acyclic carbon-to-carbon double bonds, e.g., di- or tri-cyanovinyl, methine
    • 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
    • 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
    • B41M5/39—Dyes containing one or more carbon-to-nitrogen double bonds, e.g. azomethine
    • 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 process for the transfer of cationic dyes with cyanine chromophore, in their deprotonated, electrically neutral form from a support to a coated paper.
  • a transfer sheet which contains a sublimable dye, optionally together with a binder, on a support is heated with a heating head by means of short heating impulses from the back, the dye subliming or evaporating and transferring it onto a paper serving as the recording medium becomes.
  • 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.
  • the color recording is carried out using the three subtractive primary colors yellow, magenta and cyan (and possibly black).
  • the dyes used should have the following properties: - easy sublimability or vaporizability (in general this requirement is most difficult to meet with cyan dyes); - high thermal and photochemical stability as well as resistance to moisture and chemical substances; - have suitable shades for the subtractive color mixture; - have a high molecular absorption coefficient - be easily technically accessible.
  • DE-A-2 359 515 proposes a process for dyeing and printing polyacrylonitrile fabric, salts of cationic dyes being transferred from a support to the polyacrylonitrile material under the action of heat.
  • the salts are said to be derived from acids, whose pK A value is greater than 3.
  • the thermal transfer of these salts leads to insufficient colorations, since a high energy is required to convert these color salts into the gas phase by evaporation or sublimation.
  • the dyes are partially decomposed under these conditions.
  • EP-A-178 832 describes the thermal transfer of salts of cationic dyes with soft anionic bases on polyester.
  • DE-A-2 521 988 teaches the dyeing and printing of polyacrylonitrile by thermal transfer of electroneutral, deprotonated cationic dyes in the presence of an additional indicator dye.
  • the presence of an indicator dye is necessary to avoid the formation of faulty prints.
  • the thermal transfer takes place at a temperature of 195 ° C.
  • many cationic dyes are not heat-stable in the form of their free color base, i.e. partial neutral decomposition often occurs during exposure to heat.
  • Cationic dyes with cyanine chromophore are understood to mean those dyes which have conjugated double bonds, with a nitrogen atom at at least one end of the conjugated system, and in which the delocalization of the positive charge takes place in an alternating manner along the conjugated system (chromophore chain).
  • the delocalization of the positive charge is graphically represented in a manner known per se by a dotted line along the conjugate system, in which case only the single bond is drawn in the formulas.
  • Cationic dyes whose cation has the formula I are preferably transferred in the R1 R2 and R7 are the same or different and are each independently hydrogen, C1-C4-alkyl, which is optionally substituted by C1-C4-alkoxy, C1-C4-alkylthio, halogen, cyano, hydroxy or phenyl or C5-C7-cycloalkyl or R1 and R2 together with the nitrogen atom connecting them form a 5- or 6-membered, saturated heterocyclic radical, R3 and R5 are the same or different and are each independently hydrogen, C1-C4-alkyl, C1-C4-alkoxy or halogen, R4 is hydrogen or, together with R5, a fused benzo ring, R6 is hydrogen, C1-C4-alkyl, which is optionally substituted by C1-C4-alkoxy, C1-C4-alkylthio, halogen, cyano, hydroxy or phenyl, C
  • R14 represents hydrogen, C1-C4 alkyl, which is optionally substituted by halogen, hydroxy or C1-C4-alkoxy, or C1-C4-alkoxy
  • R15 and R16 are the same or different and are each independently hydrogen, C1-C4-alkyl, optionally substituted by halogen, hydroxy, C1 -C4-alkoxy or phenyl is substituted, or phenyl optionally substituted by C1-C4-alkyl, C1-C4-alkoxy or halogen
  • W represents sulfur or di-C1-C4-alkylmethylene and T represents the remainder CH or nitrogen
  • R12 is hydrogen, C1-C4-alkyl, which is optionally substituted by halogen or C1-C4-alkoxy, or phenyl optionally substituted by C1-C4-alkyl, C
  • alkyl radicals occurring in the formulas I and II can be either straight-chain or branched. Fluorine, chlorine or bromine are particularly preferred as halogen.
  • R1, R2, R6 and R7 in formula I are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-sec-butoxyethyl, 2-methoxypropyl, 1-methoxyprop-2-yl, 2-methoxybutyl, 2-ethoxybutyl, 4-isopropoxybutyl; 2-methylthioethyl, 2-ethylthioethyl, 2-propylthioethyl, 2-isopropylthioethyl, 2-butylthioethyl, 2-isobutylthioethyl, 2-methylthiopropyl, 2-ethylthioprop-1-yl, 2-methylthi
  • R1 and R2 in formula I together with the nitrogen atom connecting them also represent, for example, the following heterocyclic radicals: pyrrolidino, piperidino, morpholino, N-methylpiperazino, N-ethylpiperazino, N-propylpiperazino, N-isopropylpiperazino, N-butylpiperazino, N-isobutylpiperaz N-sec-butylpiperazino.
  • R6 in formula I also represents, for example, phenyl; 2-methylphenyl, 2-ethylphenyl, 2-propylphenyl, 2-isopropylphenyl, 2-butylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,4,6-trimethylphenyl; 2-methoxyphenyl, 2-ethoxyphenyl, 2-propoxyphenyl, 2-isopropoxyphenyl, 2-butoxyphenyl, 2,4-dimethoxyphenyl, 2,6-dimethoxyphenyl; 2-methoxy-4-methylphenyl; 2-fluorophenyl, 2-chlorophenyl, 2-bromophenyl, 2,4-dichlorophenyl or 2,4,6-trichlorophenyl.
  • R3 and R5 in formula I are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; Methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy; Fluorine, chlorine, bromine or iodine.
  • R12, R13, R14, R15 and R16 in formula II are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-sec-butoxyethyl, 2-methoxypropyl, 1-methoxyprop-2-yl, 2-methoxybutyl, 2-ethoxybutyl, 4-isopropoxybutyl; Chloromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 2-chloroethyl, 2-bromoethyl, pentafluoroethyl, 2-chloro-1,1,2,2-tetrafluoroethyl or nonafluorobutyl.
  • R12 and R15 and R16 in formula II are furthermore, for example, phenyl; 2-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 4-ethylphenyl, 4-isopropylphenyl, 4-butylphenyl, 2,4-dimethylphenyl, 2,4,6-trimethylphenyl; 2-methoxyphenyl, 4-methoxyphenyl, 4-ethoxyphenyl, 2,4-dimethoxyphenyl; 2-chlorophenyl, 4-fluorophenyl, 4-bromophenyl or 2,6-dichlorophenyl.
  • R14 in formula II can further e.g. Methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy mean.
  • R14, R15 and R16 also mean, for example, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.
  • R14 and R15 can also mean, for example, benzyl or 2-phenylethyl.
  • W in formula II stands for example for sulfur; Prop-2-ylidene, but-2-ylidene, pent-3-ylidene, hex-2-ylidene, hept-4-ylidene or non-5-ylidene.
  • a particularly preferred procedure is that cationic dyes whose cation has the formula I in which R1, R2 and R7 are the same or different and are each independently hydrogen or C1-C4-alkyl, optionally by C1-C4-alkoxy , Halogen, cyano or hydroxy is substituted, or R1 and R2 together with the nitrogen atom connecting them pyrrolidino, piperidino or morpholino, R3 and R5 are the same or different and are each independently hydrogen, C1-C Alkyl-alkyl or C1-C4-alkoxy, R4 hydrogen, R6 the rest in which R8 and R9 are the same or different and are each independently hydrogen, C1-C4-alkyl or C1-C4-alkoxy and R10 are hydrogen and A is oxygen, in their deprotonated electrically neutral form.
  • Another particularly preferred procedure consists in that cationic dyes, the cation of which has the formula I, in which R1, R2 and R7 are the same or different and are each independently hydrogen or C1-C4-alkyl, which may be substituted by C1-C4- Alkoxy, halogen, cyano or hydroxy is substituted, or R1 and R2 together with the nitrogen atom connecting them pyrrolidino, piperidino or morpholino, R3 and R5 are the same or different and are each independently hydrogen, C1-C4-alkyl or C1-C4-alkoxy , R4 is hydrogen, R6 is C1-C4-alkyl, which is optionally substituted by C1-C4-alkoxy, halogen, cyano or hydroxy, and A is oxygen, in its deprotonated, electrically neutral form.
  • R1, R2 and R7 are the same or different and are each independently hydrogen or C1-C4-alkyl, which may be substituted by C
  • Another particularly preferred procedure consists in that cationic dyes, the cation of which has the formula II, in the R11 the heterocyclic radical in which R14 is hydrogen, R15 is C1-C4-alkyl and W is di-C1-C4-alkylmethylene, R12 is phenyl substituted by C1-C4-alkyl or C1-C4-alkoxy, R13 is hydrogen, X and Y are each the rest CH and m 0 mean, in their deprotonated, electrically neutral form.
  • cationic dyes suitable for the process according to the invention which are transferred in their deprotonated, electrically neutral form, are those whose cations have the formulas III and IV in which R17 each represents C1-C4 alkyl.
  • the cationic dyes in question are in salt form and each have an anion. All customary anions can be considered as anions, and fluoride, chloride, bromide, iodide, sulfate, methosulfate, ethosulfate, carbonate, perchlorate, borate, tetrafluoroborate, tetrachlorozincate, phosphate, methyl sulfonate, phenyl sulfonate, 4-methylphenyl sulfate formate or carboxylate should be mentioned in particular , Acetate, propionate, butyrate, 2-ethylhexanoate, benzoate or 4-methylbenzoate.
  • tetrachlorozincate salts to produce the deprotonated, electrically neutral dye form is preferred.
  • the dyes whose cations correspond to formulas I to IV are known per se or can be obtained by methods known per se.
  • those dyes whose cation corresponds to the formula I in which A represents oxygen are obtained according to those described in DE-A-2 158 121, DE-A-3 011 154, EP-A-5451, EP- A-38736 or GB-A-1 018 797 specified manufacturing methods.
  • the other cationic dyes which are transferred in their deprotonated, electrically neutral form in the process according to the invention, can also be prepared by processes known per se, such as those e.g. in K. Venkataraman "The Chemistry of Synthetic Dyes", Volume IV, p. 161; Ullmanns Encyklopadie der Technischen Chemie, 4th edition, volume 13, p. 571; or Rev. Prog. Coloration, Vol. 5, p. 65, 1974.
  • Suitable solvents are inert organic solvents, e.g. Isobutanol, toluene, xylene or chlorobenzene. These solutions are then treated with excess alkali alkanolate, e.g. Sodium methanolate or sodium ethanolate are added to convert the cationic dye into its deprotonated, electrically neutral form. It has proven advantageous to work with a 1.1- to 1.3-fold molar excess, based on the cationic dye, of alkali metal alkoxide.
  • the resulting solution containing the deprotonated, electrically neutral dye is processed with a binder to form a printing ink.
  • the printing ink is applied to the inert carrier using a doctor blade and the dyeing is air-dried.
  • binders are ethyl cellulose, polysulfones or polyether sulfones.
  • Inert carriers are, for example, tissue paper, blotting paper or glassine paper as well as plastic films with good heat resistance, for example metal-coated polyester, polyamide or polyimide.
  • the thickness of the carrier is preferably 3 to 30 ⁇ m. Further carrier materials, binders and solvents suitable for the process according to the invention for the production of the printing inks are described in DE-A-3 524 519.
  • Acceptors in the process according to the invention are coated papers, in particular those with an acid-modified coating.
  • Corresponding organic or inorganic materials that are sufficiently thermally stable serve as coating materials.
  • Suitable organic coating materials are e.g. acid-modified polyacrylonitrile, condensation products based on phenol / formaldehyde (see e.g. US-A-4 082 713), special salicylic acid derivatives (see e.g. DE-A-2 631 832) or acid-modified polyester, the latter being preferred.
  • inorganic coating materials are acid-activated clays, as used in carbonless papers (see e.g. Stamm für Textilfabrikation, volume 21, page 767, 1982).
  • the deprotonated dye is transferred from the carrier to the acceptor by means of a thermal head which must deliver sufficient heating power to the carrier so that the deprotonated dye evaporates or sublimates within a few milliseconds and is thereby transferred to the plastic-coated, acid-modified paper.
  • the transfer takes place at a temperature of 100 to 400 ° C, preferably 150 to 300 ° C.
  • an acidic aftertreatment e.g. with gaseous hydrogen chloride or with dilute acetic acid.
  • the thermal transfer was carried out with large-area heating jaws instead of a thermal head.
  • a binder was not used in the production of the dye carrier to be tested.
  • a saturated solution of the cationic dye in the form of the tetrachlorozincate is prepared in a mixture of isobutanol and chlorobenzene (1: 1 v / v).
  • a 1.2 molar excess, based on the cationic dye, of sodium methoxide is added to this solution, the deprotonated, electrically neutral form of the dye being formed.
  • the formation of the color base can easily be recognized by the resulting change in color of the reaction mixture.
  • the mixture is then filtered off and the filtrate is drawn off one to five times on carrier paper using a 20 ⁇ m doctor blade and air-dried. If necessary, the backing paper can also be sprayed with filtrate.
  • the paper layer (donor) coated with the dye to be tested is placed with the side on which the dye layer is located on a coated paper (acceptor) and pressed on.
  • the transmitter / acceptor is then wrapped with aluminum foil and heated between two heated plates for 30 seconds. (The relatively long period of 30 seconds is chosen for metrological reasons. This ensures that the acceptor can be optimally measured photometrically after the transfer has taken place). If a paper coated with polyester is used as an acceptor, the paper is briefly treated with gaseous hydrogen chloride after the transfer.
  • the amount of dye migrated into the paper is determined photometrically.
  • the temperature T * [° C] is additionally taken from the plots, at which the extinction A of the colored paper reaches the value 1.
  • the cationic dyes listed in Tables 1 and 2 below were converted into their deprotonated, electrically neutral form by method A) and placed on a support, which was tested for sublimation or evaporation behavior by method B). Paper coated with polyester was used as the acceptor. The resulting color tone and the thermal transfer parameters T * and ⁇ E T are listed in the tables.
  • the cationic dyes mentioned in Tables 3 and 4 below were converted into their deprotonated, electrically neutral form by method A) and placed on a support, which was tested for sublimation or evaporation behavior by method B).
  • a paper with acid-activated clay served as an acceptor as a coating material. The transfer took place here for 30 seconds at a temperature of 130 ° C.

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  • Optics & Photonics (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
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Abstract

Verfahren zur Übertragung von Farbstoffen von einem Träger auf einen Acceptor durch Sublimation oder Verdampfung der Farbstoffe mit Hilfe eines Thermokopfs, wobei man einen Träger verwendet, auf dem sich kationische Farbstoffe mit Cyaninchromophor, die mindestens eine N-H-Gruppierung aufweisen, die Bestandteil des Cyaninchromophors ist, in ihrer an der N-H-Gruppierung deprotonierten, elektrisch neutralen Form befinden und diese deprotonierten Farbstoffe auf ein beschichtetes Papier überträgt.Process for transferring dyes from a support to an acceptor by sublimation or evaporation of the dyes with the aid of a thermal head, using a support on which cationic dyes with cyanine chromophore, which have at least one NH group, which is part of the cyanine chromophore, are in their electrically neutral form deprotonated on the NH group and transfers these deprotonated dyes to a coated paper.

Description

Die vorliegende Erfindung betrifft ein neues Verfahren zur Übertragung von kationischen Farbstoffen mit Cyaninchromophor, in ihrer deprotonierten, elektrisch neutralen Form von einem Träger auf ein beschichtetes Papier.The present invention relates to a new process for the transfer of cationic dyes with cyanine chromophore, in their deprotonated, electrically neutral form from a support to a coated paper.

Beim Sublimations-Transferverfahren wird ein Transferblatt, welches einen sublimierbaren Farbstoff, gegebenenfalls zusammen mit einem Bindemittel, auf einem Träger enthält, mit einem Heizkopf durch kurze Heizimpulse von der Rückseite her erhitzt, wobei der Farbstoff sublimiert oder verdampft und auf ein als Aufnahmemedium dienendes Papier transferiert wird. Der wesentliche Vorteil dieses Verfahrens besteht darin, daß die Steuerung der zu übertragenden Farbstoffmenge (und damit die Farbabstufung) durch Einstellung der an den Heizkopf abzugebenden Energie leicht möglich ist.In the sublimation transfer process, a transfer sheet which contains a sublimable dye, optionally together with a binder, on a support is heated with a heating head by means of short heating impulses from the back, the dye subliming or evaporating and transferring it onto a paper serving as the recording medium becomes. 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.

Allgemein wird die Farbaufzeichnung unter Verwendung der drei subtraktiven Grundfarben Gelb, Magenta und Cyan (und gegebenenfalls Schwarz) durchge­führt. Um eine optimale Farbaufzeichnung zu ermöglichen, sollten die dabei verwendeten Farbstoff folgende Eingenschaften besitzen:
- leichte Sublimier- oder Verdampfbarkeit (im allgemeinen ist diese Anforderung bei den Cyanfarbstoffen am schwierigsten zu erfüllen);
- hohe thermische und photochemische Stabilität sowie Resistenz gegen Feuchtigkeit und chemische Stoffe;
- geeignete Farbtöne für die subtraktive Farbmischung aufweisen;
- einen hohen molekularen Absorptionskoeffizienten aufweisen
- leicht technisch zugänglich sein.In general, the color recording is carried out using the three subtractive primary colors yellow, magenta and cyan (and possibly black). In order to enable optimal color recording, the dyes used should have the following properties:
- easy sublimability or vaporizability (in general this requirement is most difficult to meet with cyan dyes);
- high thermal and photochemical stability as well as resistance to moisture and chemical substances;
- have suitable shades for the subtractive color mixture;
- have a high molecular absorption coefficient
- be easily technically accessible.

Die meisten der bekannten, für den thermischen Transferdruck verwendeten Farbstoffe erfüllen diese Forderungen jedoch nicht in ausreichendem Maße.Most of the known dyes used for thermal transfer printing, however, do not sufficiently meet these requirements.

So wird in der DE-A-2 359 515 ein Verfahren zum Färben und Bedrucken von Polyacrylnitrilgewebe vorgeschlagen, wobei Salze kationischer Farbstoffe unter Wärmeeinwirkung von einem Träger auf das Polyacrylnitrilmaterial transferiert werden. Die Salze sollen sich dabei von Säuren ableiten, deren pKA-Wert größer als 3 ist. Es hat sich jedoch gezeigt, daß der Thermotransfer dieser Salze nur zu ungenügenden Ausfärbungen führt, da man eine hohe Energie benötigt, um diese Farbsalze durch Verdampfung oder Sublimation in die Gasphase überzuführen. Außerdem werden die Farbstoffe unter diesen Bedingungen teilweise zersetzt.For example, DE-A-2 359 515 proposes a process for dyeing and printing polyacrylonitrile fabric, salts of cationic dyes being transferred from a support to the polyacrylonitrile material under the action of heat. The salts are said to be derived from acids, whose pK A value is greater than 3. However, it has been shown that the thermal transfer of these salts leads to insufficient colorations, since a high energy is required to convert these color salts into the gas phase by evaporation or sublimation. In addition, the dyes are partially decomposed under these conditions.

Die EP-A-178 832 beschreibt den Thermotransfer von Salzen kationischer Farbstoffe mit weichen anionischen Basen auf Polyester.EP-A-178 832 describes the thermal transfer of salts of cationic dyes with soft anionic bases on polyester.

Schließlich lehrt die DE-A-2 521 988 das Färben und Bedrucken von Polyacrylnitril durch Thermotransfer elektroneutraler, deprotonierter kationischer Farbstoffe in Gegenwart eines zusätzlichen Indikatorfarbstoffs. Die Anwesenheit eines Indikatorfarbstoffs ist notwendig, um die Bildung von fehlerhaften Drucken zu vermeiden. Der Thermotransfer erfolgt bei einer Temperatur von 195°C. Es ist aber bekannt, daß viele kationische Farbstoffe in Form ihrer freien Farbbase nicht hitzestabil sind, d.h., während der Hitzeeinwirkung tritt häufig eine partielle Zersetzung der neutralen Farbbase ein.Finally, DE-A-2 521 988 teaches the dyeing and printing of polyacrylonitrile by thermal transfer of electroneutral, deprotonated cationic dyes in the presence of an additional indicator dye. The presence of an indicator dye is necessary to avoid the formation of faulty prints. The thermal transfer takes place at a temperature of 195 ° C. However, it is known that many cationic dyes are not heat-stable in the form of their free color base, i.e. partial neutral decomposition often occurs during exposure to heat.

Aufgabe der vorliegenden Erfindung war es nun, ein Verfahren zur Übertragung von Farbstoffen bereitzustellen, wobei die Farbstoffe unter den Anwendungsbedingungen eines Thermokopfes leicht sublimier- oder verdampfbar, keine thermische und photochemische Zersetzung erleiden, sich zu Druckfarben verarbeiten lassen und den koloristischen Anforderungen genügen sollten. Außerdem sollten sie technisch leicht zugänglich sein.It was an object of the present invention to provide a process for transferring dyes, the dyes being easily sublimable or vaporizable under the conditions of use of a thermal head, not subject to thermal and photochemical decomposition, capable of being processed into printing inks and meeting the color requirements. They should also be technically easily accessible.

Es wurde gefunden, daß die Übertragung von Farbstoffen von einem Träger auf einen Acceptor durch Sublimation oder Verdampfung der Farbstoffe mit Hilfe eines Thermokopfs vorteilhaft gelingt, wenn man einen Träger verwendet, auf dem sich kationische Farbstoffe mit Cyaninchromophor, die mindestens eine N-H-Gruppierung aufweisen, die Bestandteil des Cyaninchromophors ist, in ihrer an der N-H-Gruppierung deprotonierten, elektrisch neutralen Form befinden, und diese deprotonierten Farbstoffe auf ein beschichtetes Papier überträgt.It has been found that the transfer of dyes from a support to an acceptor by sublimation or evaporation of the dyes with the aid of a thermal head is advantageously achieved if a support is used on which cationic dyes with cyanine chromophore, which have at least one NH group, which is part of the cyanine chromophore, is in its electrically neutral form deprotonated on the NH group, and transfers these deprotonated dyes to a coated paper.

Unter kationischen Farbstoffen mit Cyaninchromophor sind solche Farbstoffe zu verstehen, die konjugierte Doppelbindungen aufweisen, wobei sich an mindestens einem Ende des konjugierten Systems ein Stickstoffatom befindet, und bei denen die Delokalisierung der positiven Ladung in alternierender Weise entlang des konjugierten Systems (Chromophorkette) erfolgt.Cationic dyes with cyanine chromophore are understood to mean those dyes which have conjugated double bonds, with a nitrogen atom at at least one end of the conjugated system, and in which the delocalization of the positive charge takes place in an alternating manner along the conjugated system (chromophore chain).

Die graphische Darstellung der Delokalisierung der positiven Ladung erfolgt nach an sich bekannter Weise durch eine punktierte Linie entlang des konjugierten Systems, wobei in diesem Fall in den Formeln jeweils nur die Einfachbindung gezeichnet wird.The delocalization of the positive charge is graphically represented in a manner known per se by a dotted line along the conjugate system, in which case only the single bond is drawn in the formulas.

Vorzugsweise überträgt man kationische Farbstoffe, deren Kation die Formel I aufweist

Figure imgb0001
in der
    R¹ R² und R7 gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, C₁-C₄-Alkylthio, Halogen, Cyano, Hydroxy oder Phenyl substituiert ist oder C₅-C₇-Cycloalkyl oder R¹ und R² zusammen mit dem sie verbindenden Stickstoffatom einen 5- oder 6-gliedrigen, gesättigten heterocyclischen Rest,
    R³ und R⁵ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen,
    R⁴ Wasserstoff oder zusammen mit R⁵ einen anellierten Benzoring,
    R⁶ Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, C₁-C₄-Alkylthio, Halogen, Cyano, Hydroxy oder Phenyl substituiert ist, C₅-C₇-Cycloalkyl oder den Rest
Figure imgb0002
 in dem R⁸, R⁹ und R¹⁰ gleich oder verschieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen stehen, und
    A Sauerstoff oder Schwefel bedeuten, in ihrer deprotonierten, elektrisch neutralen Form.Cationic dyes whose cation has the formula I are preferably transferred
Figure imgb0001
 in the
R¹ R² and R7 are the same or different and are each independently hydrogen, C₁-C₄-alkyl, which is optionally substituted by C₁-C₄-alkoxy, C₁-C₄-alkylthio, halogen, cyano, hydroxy or phenyl or C₅-C₇-cycloalkyl or R¹ and R² together with the nitrogen atom connecting them form a 5- or 6-membered, saturated heterocyclic radical,
R³ and R⁵ are the same or different and are each independently hydrogen, C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen,
R⁴ is hydrogen or, together with R⁵, a fused benzo ring,
R⁶ is hydrogen, C₁-C₄-alkyl, which is optionally substituted by C₁-C₄-alkoxy, C₁-C₄-alkylthio, halogen, cyano, hydroxy or phenyl, C₅-C₇-cycloalkyl or the rest
Figure imgb0002
 in which R⁸, R⁹ and R¹⁰ are the same or different and each independently represent hydrogen, C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen, and
A is oxygen or sulfur, in its deprotonated, electrically neutral form.

Eine weitere bevorzugte Verfahrensweise besteht darin, daß man kationische Farbstoffe, deren Kation die Formel II aufweist

Figure imgb0003
in der
    R¹¹ die heterocyclischen Reste
Figure imgb0004
 in denen R¹⁴ für Wasserstoff, C₁-C₄-Alkyl,
das gegebenenfalls durch Halogen, Hydroxy oder C₁-C₄-Alkoxy substituiert ist, oder C₁-C₄-Alkoxy, R¹⁵ und R¹⁶ gleich oder verschieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch Halogen, Hydroxy, C₁-C₄-Alkoxy oder Phenyl substituiert ist, oder gegebenenfalls durch C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen substituiertes Phenyl, W für Schwefel oder Di-C₁-C₄-Alkylmethylen und T für den Rest CH oder Stickstoff stehen,
    R¹² Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch Halogen oder C₁-C₄-Alkoxy substituiert ist, oder gegebenenfalls durch C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen substituiertes Phenyl,
    R¹³ Wasserstoff oder C₁-C₄-Alkyl, das gegebenenfalls durch Halogen oder C₁-C₄-Alkoxy substituiert ist,
    X und Y gleich oder verschieden sind und unabhängig voneinander jeweils den Rest CH oder Stickstoff,
    Z den Rest
Figure imgb0005
 und
    m 0 oder 1 bedeuten, oder in der, falls m 1 ist, die Gruppierung
Figure imgb0006
 steht, in denen
R¹³ und R¹⁵ jeweils die obengenannte Bedeutung besitzen, mit der Maßgabe, daß wenn m 0 ist, X und Y nicht gleichzeitig die Bedeutung von Stickstoff besitzen sollen, in ihrer deprotonierten, elektrisch neutralen Form überträgt.Another preferred procedure is to use cationic dyes whose cation has the formula II
Figure imgb0003
 in the
R¹¹ the heterocyclic radicals
Figure imgb0004
 in which R¹⁴ represents hydrogen, C₁-C₄ alkyl,
which is optionally substituted by halogen, hydroxy or C₁-C₄-alkoxy, or C₁-C₄-alkoxy, R¹⁵ and R¹⁶ are the same or different and are each independently hydrogen, C₁-C₄-alkyl, optionally substituted by halogen, hydroxy, C₁ -C₄-alkoxy or phenyl is substituted, or phenyl optionally substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen, W represents sulfur or di-C₁-C₄-alkylmethylene and T represents the remainder CH or nitrogen,
R¹² is hydrogen, C₁-C₄-alkyl, which is optionally substituted by halogen or C₁-C₄-alkoxy, or phenyl optionally substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen,
R¹³ is hydrogen or C₁-C₄-alkyl, which is optionally substituted by halogen or C₁-C₄-alkoxy,
X and Y are the same or different and each independently the radical CH or nitrogen,
Z the rest
Figure imgb0005
 and
m is 0 or 1, or in which, if m is 1, the grouping
Figure imgb0006
 stands in which
R¹³ and R¹⁵ each have the meaning given above, with the proviso that when m is 0, X and Y should not simultaneously have the meaning of nitrogen, in their deprotonated, electrically neutral form.

Die in den Formeln I und II auftretenden Alkylreste können sowohl geradkettig als auch verzweigt sein. Als Halogen werden jeweils Fluor, Chlor oder Brom besonders bevorzugt.The alkyl radicals occurring in the formulas I and II can be either straight-chain or branched. Fluorine, chlorine or bromine are particularly preferred as halogen.

R¹, R², R⁶ und R⁷ in Formel I stehen beispielsweise für Wasserstoff; Methyl, Ethyl, Propyl, Isopropyl, Butyl, Isobutyl, sec-Butyl, tert-Butyl; 2-Methoxyethyl, 2-Ethoxyethyl, 2-Propoxyethyl, 2-Isopropoxyethyl, 2-Butoxyethyl, 2-sec-Butoxyethyl, 2-Methoxypropyl, 1-Methoxyprop-2-yl, 2-Methoxybutyl, 2-Ethoxybutyl, 4-Isopropoxybutyl; 2-Methylthioethyl, 2-Ethylthioethyl, 2-Propylthioethyl, 2-Isopropylthioethyl, 2-Butylthioethyl, 2-Isobutylthioethyl, 2-Methylthiopropyl, 2-Ethylthioprop-1-yl, 2-Methylthiobutyl, 2-Ethylthiobutyl, 4-Ethylthiobutyl, 4-Propylthiobutyl; Fluormethyl, Chlormethyl, Difluormethyl, Trifluormethyl, 2-Fluorethyl, 2-Chlorethyl, 2-Bromethyl, Pentafluorethyl, 2-Chlor-1,1,2,2-Tetrafluorethyl, Nonafluorbutyl; Cyanomethyl, 2-Cyanoethyl, 2-Cyanopropyl, 3-Cyanopropyl, 2-Cyanobutyl, 4-Cyanobutyl; 2-Hydroxyethyl, 2-Hydroxypropyl, 1-Hydroxyprop-2-yl, 3-Hydroxypropyl, 2-Hydroxybutyl, 4-Hydroxybutyl; Benzyl, 2-Phenylethyl; Cyclopentyl, Cyclohexyl oder Cycloheptyl.R¹, R², R⁶ and R⁷ in formula I are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-sec-butoxyethyl, 2-methoxypropyl, 1-methoxyprop-2-yl, 2-methoxybutyl, 2-ethoxybutyl, 4-isopropoxybutyl; 2-methylthioethyl, 2-ethylthioethyl, 2-propylthioethyl, 2-isopropylthioethyl, 2-butylthioethyl, 2-isobutylthioethyl, 2-methylthiopropyl, 2-ethylthioprop-1-yl, 2-methylthiobutyl, 2-ethylthiobutyl, 4-ethylthiobutyl Propylthiobutyl; Fluoromethyl, chloromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 2-chloroethyl, 2-bromoethyl, pentafluoroethyl, 2-chloro-1,1,2,2-tetrafluoroethyl, nonafluorobutyl; Cyanomethyl, 2-cyanoethyl, 2-cyanopropyl, 3-cyanopropyl, 2-cyanobutyl, 4-cyanobutyl; 2-hydroxyethyl, 2-hydroxypropyl, 1-hydroxyprop-2-yl, 3-hydroxypropyl, 2-hydroxybutyl, 4-hydroxybutyl; Benzyl, 2-phenylethyl; Cyclopentyl, cyclohexyl or cycloheptyl.

R¹ und R² in Formel I stehen außerdem zusammen mit dem sie verbindenden Stickstoffatom beispielsweise für folgende heterocyclischen Reste: Pyrrolidino, Piperidino, Morpholino, N-Methylpiperazino, N-Ethylpiperazino, N-Propylpiperazino, N-Isopropylpiperazino, N-Butylpiperazino, N-Isobutylpiperazino oder N-sec-Butylpiperazino.R1 and R2 in formula I together with the nitrogen atom connecting them also represent, for example, the following heterocyclic radicals: pyrrolidino, piperidino, morpholino, N-methylpiperazino, N-ethylpiperazino, N-propylpiperazino, N-isopropylpiperazino, N-butylpiperazino, N-isobutylpiperaz N-sec-butylpiperazino.

R⁶ in Formel I steht außerdem beispielsweise für Phenyl; 2-Methylphenyl, 2-Ethylphenyl, 2-Propylphenyl, 2-Isopropylphenyl, 2-Butylphenyl, 2,6-Dimethylphenyl, 2,6-Diethylphenyl, 2,4,6-Trimethylphenyl; 2-Methoxyphenyl, 2-Ethoxyphenyl, 2-Propoxyphenyl, 2-Isopropoxyphenyl, 2-Butoxyphenyl, 2,4-Dimethoxyphenyl, 2,6-Dimethoxyphenyl; 2-Methoxy-4-Methylphenyl; 2-Fluorphenyl, 2-Chlorphenyl, 2-Bromphenyl, 2,4-Dichlorphenyl oder 2,4,6-Trichlorphenyl.R⁶ in formula I also represents, for example, phenyl; 2-methylphenyl, 2-ethylphenyl, 2-propylphenyl, 2-isopropylphenyl, 2-butylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,4,6-trimethylphenyl; 2-methoxyphenyl, 2-ethoxyphenyl, 2-propoxyphenyl, 2-isopropoxyphenyl, 2-butoxyphenyl, 2,4-dimethoxyphenyl, 2,6-dimethoxyphenyl; 2-methoxy-4-methylphenyl; 2-fluorophenyl, 2-chlorophenyl, 2-bromophenyl, 2,4-dichlorophenyl or 2,4,6-trichlorophenyl.

R³ und R⁵ in Formel I stehen beispielsweise für Wasserstoff; Methyl, Ethyl, Propyl, Isopropyl, Butyl, Isobutyl, sec-Butyl, tert-Butyl; Methoxy, Ethoxy, Propoxy, Isopropoxy, Butoxy, Isobutoxy oder sec-Butoxy; Fluor, Chlor, Brom oder Iod.R³ and R⁵ in formula I are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; Methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy; Fluorine, chlorine, bromine or iodine.

R¹², R¹³, R¹⁴, R¹⁵ und R¹⁶ in Formel II stehen beispielsweise für Wasserstoff; Methyl, Ethyl, Propyl, Isopropyl, Butyl, Isobutyl, sec-Butyl, tert-Butyl; 2-Methoxyethyl, 2-Ethoxyethyl, 2-Propoxyethyl, 2-Isopropoxyethyl, 2-Butoxyethyl, 2-sec-Butoxyethyl, 2-Methoxypropyl, 1-Methoxyprop-2-yl, 2-Methoxybutyl, 2-Ethoxybutyl, 4-Isopropoxybutyl; Chlormethyl, Difluormethyl, Trifluormethyl, 2-Fluorethyl, 2-Chlorethyl, 2-Bromethyl, Pentafluorethyl, 2-Chlor-1,1,2,2-Tetrafluorethyl oder Nonafluorbutyl.R¹², R¹³, R¹⁴, R¹⁵ and R¹⁶ in formula II are, for example, hydrogen; Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl; 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-sec-butoxyethyl, 2-methoxypropyl, 1-methoxyprop-2-yl, 2-methoxybutyl, 2-ethoxybutyl, 4-isopropoxybutyl; Chloromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 2-chloroethyl, 2-bromoethyl, pentafluoroethyl, 2-chloro-1,1,2,2-tetrafluoroethyl or nonafluorobutyl.

R¹² sowie R¹⁵ und R¹⁶ in Formel II stehen weiterhin beispielsweise für Phenyl; 2-Methylphenyl, 4-Methylphenyl, 2-Ethylphenyl, 4-Ethylphenyl, 4-Isopropylphenyl, 4-Butylphenyl, 2,4-Dimethylphenyl, 2,4,6-Trimethylphenyl; 2-Methoxyphenyl, 4-Methoxyphenyl, 4-Ethoxyphenyl, 2,4-Dimethoxyphenyl; 2-Chlorphenyl, 4-Fluorphenyl, 4-Bromphenyl oder 2,6-Dichlorphenyl.R¹² and R¹⁵ and R¹⁶ in formula II are furthermore, for example, phenyl; 2-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 4-ethylphenyl, 4-isopropylphenyl, 4-butylphenyl, 2,4-dimethylphenyl, 2,4,6-trimethylphenyl; 2-methoxyphenyl, 4-methoxyphenyl, 4-ethoxyphenyl, 2,4-dimethoxyphenyl; 2-chlorophenyl, 4-fluorophenyl, 4-bromophenyl or 2,6-dichlorophenyl.

R¹⁴ in Formel II kann weiterhin z.B. Methoxy, Ethoxy, Propoxy, Isopropoxy, Butoxy, Isobutoxy oder sec-Butoxy bedeuten.R¹⁴ in formula II can further e.g. Methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy mean.

R¹⁴, R¹⁵ und R¹⁶ bedeuten weiterhin beispielsweise 2-Hydroxyethyl, 2-Hydroxypropyl, 3-Hydroxypropyl, 2-Hydroxybutyl oder 4-Hydroxybutyl.R¹⁴, R¹⁵ and R¹⁶ also mean, for example, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.

R¹⁴ und R¹⁵ können weiterhin auch z.B. Benzyl oder 2-Phenylethyl bedeuten.R¹⁴ and R¹⁵ can also mean, for example, benzyl or 2-phenylethyl.

W in Formel II steht beispielsweise für Schwefel; Prop-2-yliden, But-2-yliden, Pent-3-yliden, Hex-2-yliden, Hept-4-yliden oder Non-5-yliden.W in formula II stands for example for sulfur; Prop-2-ylidene, but-2-ylidene, pent-3-ylidene, hex-2-ylidene, hept-4-ylidene or non-5-ylidene.

Eine besonders bevorzugte Verfahrensweise besteht darin, daß man kationische Farbstoffe, deren Kation die Formel I aufweist, in der R¹, R² und R⁷ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff oder C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, Halogen, Cyano oder Hydroxy substituiert ist, oder R¹ und R² zusammen mit dem sie verbindenden Stickstoffatom Pyrrolidino, Piperidino oder Morpholino, R³ und R⁵ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl oder C₁-C₄-Alkoxy, R⁴ Wasserstoff, R⁶ den Rest

Figure imgb0007
in dem R⁸ und R⁹ gleich oder verschieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl oder C₁-C₄-Alkoxy und R¹⁰ für Wasserstoff stehen und A Sauerstoff bedeuten, in ihrer deprotonierten elektrisch neutralen Form überträgt.A particularly preferred procedure is that cationic dyes whose cation has the formula I in which R¹, R² and R⁷ are the same or different and are each independently hydrogen or C₁-C₄-alkyl, optionally by C₁-C₄-alkoxy , Halogen, cyano or hydroxy is substituted, or R¹ and R² together with the nitrogen atom connecting them pyrrolidino, piperidino or morpholino, R³ and R⁵ are the same or different and are each independently hydrogen, C₁-C Alkyl-alkyl or C₁-C₄-alkoxy, R⁴ hydrogen, R⁶ the rest
Figure imgb0007
 in which R⁸ and R⁹ are the same or different and are each independently hydrogen, C₁-C₄-alkyl or C₁-C₄-alkoxy and R¹⁰ are hydrogen and A is oxygen, in their deprotonated electrically neutral form.

Eine weitere besonders bevorzugte Verfahrensweise besteht darin, daß man kationische Farbstoffe, deren Kation die Formel I aufweist, in der R¹, R² und R⁷ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff oder C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, Halogen, Cyano oder Hydroxy subsituiert ist, oder R¹ und R² zusammen mit dem sie verbindenden Stickstoffatom Pyrrolidino, Piperidino oder Morpholino, R³ und R⁵ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl oder C₁-C₄-Alkoxy, R⁴ Wasserstoff, R⁶ C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, Halogen, Cyano oder Hydroxy subsituiert ist, und A Sauerstoff bedeutet, in ihrer deprotonierten elektrisch neutralen Form überträgt.Another particularly preferred procedure consists in that cationic dyes, the cation of which has the formula I, in which R¹, R² and R⁷ are the same or different and are each independently hydrogen or C₁-C₄-alkyl, which may be substituted by C₁-C₄- Alkoxy, halogen, cyano or hydroxy is substituted, or R¹ and R² together with the nitrogen atom connecting them pyrrolidino, piperidino or morpholino, R³ and R⁵ are the same or different and are each independently hydrogen, C₁-C₄-alkyl or C₁-C₄-alkoxy , R⁴ is hydrogen, R⁶ is C₁-C₄-alkyl, which is optionally substituted by C₁-C₄-alkoxy, halogen, cyano or hydroxy, and A is oxygen, in its deprotonated, electrically neutral form.

Ganz besonders hervorzuheben ist die Übertragung kationischer Farbstoffe, deren Kation die Formel I aufweist, in der R¹, R² und R⁷ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff oder C₁-C₄-Alkyl, R³ und R⁵ jeweils Wasserstoff, oder C₁-C₄-Alkyl, R⁴ Wasserstoff, R⁶ Wasserstoff, C₁-C₄-Alkyl oder den Rest

Figure imgb0008
in dem R8 und R⁹ gleich oder verschieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl oder C₁-C₄-Alkoxy und R¹⁰ für Wasserstoff stehen, und A Sauerstoff bedeuten.Particularly noteworthy is the transfer of cationic dyes whose cation has the formula I in which R¹, R² and R⁷ are the same or different and are each independently hydrogen or C₁-C₄-alkyl, R³ and R⁵ are each hydrogen, or C₁-C₄- Alkyl, R⁴ hydrogen, R⁶ hydrogen, C₁-C₄-alkyl or the rest
Figure imgb0008
 in which R8 and R⁹ are the same or different and are each independently hydrogen, C₁-C₄-alkyl or C₁-C₄-alkoxy and R¹⁰ is hydrogen, and A is oxygen.

Eine weitere besonders bevorzugte Verfahrensweise besteht darin, daß man kationische Farbstoffe, deren Kation die Formel II aufweist, in der R¹¹ den heterocyclischen Rest

Figure imgb0009
in dem R¹⁴ für Wasserstoff, R¹⁵ für C₁-C₄-Alkyl und W für Di-C₁-C₄-Alkylmethylen stehen, R¹² durch C₁-C₄-Alkyl oder C₁-C₄-Alkoxy substituiertes Phenyl, R¹³ Wasserstoff, X und Y jeweils den Rest CH und m 0 bedeuten, in ihrer deprotonierten, elektrisch neutralen Form überträgt.Another particularly preferred procedure consists in that cationic dyes, the cation of which has the formula II, in the R¹¹ the heterocyclic radical
Figure imgb0009
 in which R¹⁴ is hydrogen, R¹⁵ is C₁-C₄-alkyl and W is di-C₁-C₄-alkylmethylene, R¹² is phenyl substituted by C₁-C₄-alkyl or C₁-C₄-alkoxy, R¹³ is hydrogen, X and Y are each the rest CH and m 0 mean, in their deprotonated, electrically neutral form.

Weitere für das erfindungsgemäße Verfahren geeignete kationische Farbstoffe, die in ihrer deprotonierten, elektrisch neutralen Form übertragen werden, sind solche deren Kationen die Formeln III und IV aufweisen

Figure imgb0010
in denen R¹⁷ jeweils C₁-C₄-Alkyl bedeutet.Other cationic dyes suitable for the process according to the invention, which are transferred in their deprotonated, electrically neutral form, are those whose cations have the formulas III and IV
Figure imgb0010
 in which R¹⁷ each represents C₁-C₄ alkyl.

In den bisherigen Ausführungen wurden von den genannten kationischen Farbstoffen jeweils nur deren Kationen (Formeln I bis IV) genannt. Es ist jedoch selbstverständlich, daß die betreffenden kationischen Farbstoffe in Salzform vorliegen und jeweils noch ein Anion aufweisen. Als Anionen kommen alle gebräuchlichen Anionen in Betracht, insbesondere zu nennen sind Fluorid, Chlorid, Bromid, Iodid, Sulfat, Methosulfat, Ethosulfat, Carbonat, Perchlorat, Borat, Tetrafluoroborat, Tetrachlorozinkat, Phosphat, Methylsulfonat, Phenylsulfonat, 4-Methylphenylsulfonat oder Carboxylate wie Formiat, Acetat, Propionat, Butyrat, 2-Ethylhexanoat, Benzoat oder 4-Methylbenzoat. Die Verwendung von Tetrachlorozinkat-Salzen zur Erzeugung der deprotonierten, elektrisch neutralen Farbstoff-Form ist dabei bevorzugt.In the previous statements, only the cations (formulas I to IV) of the cationic dyes mentioned were mentioned. However, it goes without saying that the cationic dyes in question are in salt form and each have an anion. All customary anions can be considered as anions, and fluoride, chloride, bromide, iodide, sulfate, methosulfate, ethosulfate, carbonate, perchlorate, borate, tetrafluoroborate, tetrachlorozincate, phosphate, methyl sulfonate, phenyl sulfonate, 4-methylphenyl sulfate formate or carboxylate should be mentioned in particular , Acetate, propionate, butyrate, 2-ethylhexanoate, benzoate or 4-methylbenzoate. The use of tetrachlorozincate salts to produce the deprotonated, electrically neutral dye form is preferred.

Die Farbstoffe, deren Kationen den Formeln I bis IV entsprechen, sind an sich bekannt oder können nach an sich bekannten Methoden erhalten werden.The dyes whose cations correspond to formulas I to IV are known per se or can be obtained by methods known per se.

So erhält man beispielsweise diejenigen Farbstoffe, deren Kation der Formel I, in der A für Sauerstoff steht, entspricht, nach den in der DE-A-2 158 121, DE-A-3 011 154, EP-A-5451, EP-A-38736 oder GB-A-1 018 797 angegebenen Herstellmethoden. Die entsprechenden Thiazinderivate (A = Schwefel) können durch oxidative Kupplung geeigneter 1,4-Diamino­benzolderivate mit Anilinderivaten und anschließender Umsetzung mit Schwefelwasserstoff oder mit Thiosulfat hergestellt werden.For example, those dyes whose cation corresponds to the formula I in which A represents oxygen are obtained according to those described in DE-A-2 158 121, DE-A-3 011 154, EP-A-5451, EP- A-38736 or GB-A-1 018 797 specified manufacturing methods. The corresponding thiazine derivatives (A = sulfur) can be prepared by oxidative coupling of suitable 1,4-diaminobenzene derivatives with aniline derivatives and subsequent reaction with hydrogen sulfide or with thiosulfate.

Die anderen kationischen Farbstoffe, die im erfindungsgemäßen Verfahren in ihrer deprotonierten, elektrisch neutralen Form übertragen werden, können ebenfalls nach an sich bekannten Verfahren hergestellt werden, wie sie z.B. in K. Venkataraman "The Chemistry of Synthetic Dyes", Band IV, S. 161; Ullmanns Encyklopädie der Technischen Chemie, 4. Auflage, Band 13, S. 571; oder Rev. Prog. Coloration, Vol. 5, S. 65, 1974, beschrieben sind.The other cationic dyes, which are transferred in their deprotonated, electrically neutral form in the process according to the invention, can also be prepared by processes known per se, such as those e.g. in K. Venkataraman "The Chemistry of Synthetic Dyes", Volume IV, p. 161; Ullmanns Encyklopadie der Technischen Chemie, 4th edition, volume 13, p. 571; or Rev. Prog. Coloration, Vol. 5, p. 65, 1974.

Zur Herstellung der für das erfindungsgemäße Verfahren benötigten Farbstoffträger werden zweckmäßig zunächst Lösungen der kationischen Farbstoffe, zweckmäßig in Form des Tetrachlorozinkat-Salzes, bereitet. Geeignete Lösungsmittel sind inerte organische Lösungsmittel, z.B. Isobutanol, Toluol, Xylol oder Chlorbenzol. Diese Lösungen werden dann mit überschüssigem Alkalialkanolat, z.B. Natriummethanolat oder Natrium­ethanolat versetzt, um den kationischen Farbstoff in seine deprotonierte, elektrisch neutrale Form überzuführen. Es hat sich als vorteilhaft erwiesen, mit einem 1,1- bis 1,3-fachen molaren Überschuß, bezogen auf den kationischen Farbstoff, an Alkalialkanolat zu arbeiten.To prepare the dye carriers required for the process according to the invention, it is advisable first to prepare solutions of the cationic dyes, advantageously in the form of the tetrachlorozincate salt. Suitable solvents are inert organic solvents, e.g. Isobutanol, toluene, xylene or chlorobenzene. These solutions are then treated with excess alkali alkanolate, e.g. Sodium methanolate or sodium ethanolate are added to convert the cationic dye into its deprotonated, electrically neutral form. It has proven advantageous to work with a 1.1- to 1.3-fold molar excess, based on the cationic dye, of alkali metal alkoxide.

Die resultierende, den deprotonierten, elektrisch neutralen Farbstoff enthaltende Lösung wird mit einem Bindemittel zu einer Druckfarbe verarbeitet. Diese enthält den deprotonierten Farbstoff in gelöster oder dispergierter Form. Die Druckfarbe wird mittels einer Rakel auf den inerten Träger aufgetragen und die Färbung an der Luft getrocknet.The resulting solution containing the deprotonated, electrically neutral dye is processed with a binder to form a printing ink. This contains the deprotonated dye in dissolved or dispersed form. The printing ink is applied to the inert carrier using a doctor blade and the dyeing is air-dried.

Als Bindemittel kommen z.B. Ethylcellulose, Polysulfone oder Poly­ethersulfone in Betracht. Inerte Träger sind z.B. Seidenpapier, Lösch­papier oder Pergaminpapier sowie Kunststoffolien mit guter Wärmebe­ständigkeit, z.B. gegebenenfalls metallbeschichteter Polyester, Polyamid oder Polyimid. Die Dicke des Trägers beträgt vorzugsweise 3 bis 30µm. Weitere für das erfindungsgemäße Verfahren geeignete Trägermaterialien, Bindemittel sowie Lösungsmittel zur Herstellung der Druckfarben sind in der DE-A-3 524 519 beschrieben.Examples of suitable binders are ethyl cellulose, polysulfones or polyether sulfones. Inert carriers are, for example, tissue paper, blotting paper or glassine paper as well as plastic films with good heat resistance, for example metal-coated polyester, polyamide or polyimide. The thickness of the carrier is preferably 3 to 30 µm. Further carrier materials, binders and solvents suitable for the process according to the invention for the production of the printing inks are described in DE-A-3 524 519.

Acceptoren im erfindungsgemäßen Verfahren sind beschichtete Papiere, insbesondere solche mit sauer modifizierter Beschichtung. Als Beschichtungsmaterialien dienen entsprechende organische oder anorganische Materialien, die ausreichend thermostabil sind.Acceptors in the process according to the invention are coated papers, in particular those with an acid-modified coating. Corresponding organic or inorganic materials that are sufficiently thermally stable serve as coating materials.

Geeignete organische Beschichtungsmaterialien sind z.B. sauer modifizier­tes Polyacrylnitril, Kondensationsprodukte auf der Basis Phenol /Form­aldehyd (s. z.B. US-A-4 082 713), spezielle Salicylsäurederivate (s. z.B. DE-A-2 631 832) oder sauer modifizierte Polyester, wobei letztere bevorzugt sind.Suitable organic coating materials are e.g. acid-modified polyacrylonitrile, condensation products based on phenol / formaldehyde (see e.g. US-A-4 082 713), special salicylic acid derivatives (see e.g. DE-A-2 631 832) or acid-modified polyester, the latter being preferred.

Als anorganische Beschichtungsmaterialien kommen z.B. sauer aktivierte Clays in Betracht, wie sie in chemischen Durchschreibepapieren Verwendung finden (s. z.B. Wochenblatt für Papierfabrikation, Band 21, Seite 767, 1982).Examples of inorganic coating materials are acid-activated clays, as used in carbonless papers (see e.g. Wochenblatt für Papierfabrikation, volume 21, page 767, 1982).

Die Übertragung des deprotonierten Farbstoffs vom Träger auf den Acceptor erfolgt mittels eines Thermokopfs der genügend Heizleistung an den Träger abgeben muß, so daß der deprotonierte Farbstoff innerhalb einiger Millisekunden verdampft oder sublimiert und dabei auf das mit Kunststoff beschichtete, sauer modifizierte Papier transferiert wird. Der Transfer erfolgt bei einer Temperatur von 100 bis 400°C, vorzugsweise 150 bis 300°C.The deprotonated dye is transferred from the carrier to the acceptor by means of a thermal head which must deliver sufficient heating power to the carrier so that the deprotonated dye evaporates or sublimates within a few milliseconds and is thereby transferred to the plastic-coated, acid-modified paper. The transfer takes place at a temperature of 100 to 400 ° C, preferably 150 to 300 ° C.

In manchen Fällen, insbesondere bei Verwendung von Papier mit nicht sauer modifiziertem Beschichtungsmaterial, kann es von Vorteil sein, nach dem Transfer das als Acceptor dienende Papier noch einer sauren Nachbehand­lung, z.B. mit gasförmigen Chlorwasserstoff oder mit verdünnter Essig­säure, zu unterwerfen.In some cases, especially when using paper with a non-acid modified coating material, it may be advantageous to add an acidic aftertreatment, e.g. with gaseous hydrogen chloride or with dilute acetic acid.

Nachdem die Thermolabilität von elektrisch neutralen Farbbasen bekannt ist, war es überraschend, daß im erfindungsgemäßen Verfahren die kationi­schen Farbstoffe in ihrer deprotonierten, elektrisch neutralen Form unter den genannten Transferbedingungen keinen thermischen Zersetzungs- oder Umwandlungsreaktionen unterliegen, sondern in schneller und problemloser Weise auf den Acceptor übertragen werden können.After the thermolability of electrically neutral color bases is known, it was surprising that in the process according to the invention the deprotonated, electrically neutral form of the cationic dyes is not subject to thermal decomposition or conversion reactions under the transfer conditions mentioned, but rather is transferred to the acceptor in a quick and easy manner can be.

Die Erfindung soll durch die folgenden Beispiele näher erläutert werden:The invention is illustrated by the following examples:

Um das Transferverhalten der deprotonierten Farbstoffe quantitativ und in einfacher Weise prüfen zu können, wurde der Thermotransfer mit großflächigen Heizbacken anstelle eines Thermokopfes durchgeführt. Bei der Herstellung der zu prüfenden Farbstoffträger wurde auf ein Bindemittel verzichtet.In order to be able to check the transfer behavior of the deprotonated dyes quantitatively and easily, the thermal transfer was carried out with large-area heating jaws instead of a thermal head. A binder was not used in the production of the dye carrier to be tested.

A) Allgemeines Rezept für die Beschichtung der Träger mit derotoniertem FarbstoffA) General recipe for coating the carrier with derotonated dye

Zunächst wird eine gesättigte Lösung des kationischen Farbstoffs in Form des Tetrachlorozinkats in einem Gemisch aus Isobutanol und Chlorbenzol (1:1 v/v) hergestellt. Diese Lösung wird mit einem 1,2-molaren Überschuß, bezogen auf den kationischen Farbstoff, an Natriummethanolat versetzt, wobei sich dei deprotonierte, elektrische neutrale Form des Farbstoffs bildet. Die Bildung der Farbbase ist leicht zu erkennen an der resul­tierenden Farbänderung des Reaktionsgemisches. Danach wird das Gemisch abfiltriert und das Filtrat mit einer 20µm-Rakel ein- bis fünfmal auf Trägerpapier abgezogen und an der Luft getrocknet. Gegebenenfalls kann das Trägerpapier auch mit Filtrat besprüht werden.First, a saturated solution of the cationic dye in the form of the tetrachlorozincate is prepared in a mixture of isobutanol and chlorobenzene (1: 1 v / v). A 1.2 molar excess, based on the cationic dye, of sodium methoxide is added to this solution, the deprotonated, electrically neutral form of the dye being formed. The formation of the color base can easily be recognized by the resulting change in color of the reaction mixture. The mixture is then filtered off and the filtrate is drawn off one to five times on carrier paper using a 20 μm doctor blade and air-dried. If necessary, the backing paper can also be sprayed with filtrate.

B) Prüfung auf Sublimations- oder Verdampfungs-VerhaltenB) Testing for sublimation or evaporation behavior

Die mit dem zu prüfenden Farbstoff beschichtete Papierschicht (Geber) wird mit derjenigen Seite auf der sich die Farbstoffschicht befindet, auf ein beschichtetes Papier (Acceptor) gelegt und angedrückt. Geber/Acceptor werden dann mit Aluminiumfolie umwickelt und zwischen zwei beheizten Platten 30 sec lang erhitzt. (Der relativ lange Zeitraum von 30 sec wird aus meßtechnischen Gründen gewählt. Damit ist nämlich gewährleistet, daß der Acceptor nach erfolgtem Transfer in optimaler Weise photometrisch vermessen werden kann). Bei Verwendung eines mit Polyester beschichteten Papiers als Acceptor wird das Papier nach dem Transfer kurzzeitig mit gasförmigem Chlorwasserstoff behandelt.The paper layer (donor) coated with the dye to be tested is placed with the side on which the dye layer is located on a coated paper (acceptor) and pressed on. The transmitter / acceptor is then wrapped with aluminum foil and heated between two heated plates for 30 seconds. (The relatively long period of 30 seconds is chosen for metrological reasons. This ensures that the acceptor can be optimally measured photometrically after the transfer has taken place). If a paper coated with polyester is used as an acceptor, the paper is briefly treated with gaseous hydrogen chloride after the transfer.

Die in das Papier übergewanderte Farbstoffmenge wird photometrisch bestimmt. Dabei werden die aus den Remissionsmessungen erhaltenen Transmissionswerte "Tra" nach der Beziehung: A = -log Tra in Extinktionswerte umgerechnet. Trägt man dann den Logarithmus der bei verschiedenen Temperaturen (Bereich: 100 bis 200°C) gemessenen Extinktion A des jeweils angefärbten Papiers gegen die zugehörige reziproke absolute Temperatur T auf, so erhält man Geraden, aus deren Steigung die Aktivierungsenergie ΔET für das Transferexperiment berechnet wird:

Figure imgb0011
The amount of dye migrated into the paper is determined photometrically. The transmission values "Tra" obtained from the remission measurements are converted into extinction values according to the relationship: A = -log Tra. If one then plots the logarithm of the absorbance A of the respective colored paper measured at different temperatures (range: 100 to 200 ° C) against the associated reciprocal absolute temperature T, straight lines are obtained, from the slope of which the activation energy ΔE T is calculated for the transfer experiment becomes:
Figure imgb0011

Zur vollständigen Charakterisierung wird aus den Auftragungen zusätzlich die Temperatur T* [°C] entnommen, bei der die Extinktion A des angefärbten Papiers den Wert 1 erreicht.For complete characterization, the temperature T * [° C] is additionally taken from the plots, at which the extinction A of the colored paper reaches the value 1.

In den folgenden Tabellen werden jeweils nur die kationischen Formen der Farbstoffe aufgeführt. Als Anion diente, wie oben bereits genannt, in allen Fällen Tetrachlorozinkat. Me und Et in den Formeln stehen für Methyl und Ethyl.Only the cationic forms of the dyes are listed in the following tables. As already mentioned, tetrachlorozincate was used as the anion in all cases. Me and Et in the formulas stand for methyl and ethyl.

Die in den nachfolgenden Tabellen 1 und 2 genannten kationischen Farbstoffe wurden nach Methode A) in ihre deprotonierte, elektrisch neutrale Form übergeführt und auf einen Träger gebracht, dieser wurde nach Methode B) auf das Sublimations- oder Verdampfungsverhalten geprüft. Als Acceptor diente mit Polyester beschichtetes Papier. In den Tabellen sind jeweils der resultierende Farbton sowie die Thermotransferparameter T* und ΔET aufgeführt.

Figure imgb0012
Figure imgb0013
Figure imgb0014
Figure imgb0015
 The cationic dyes listed in Tables 1 and 2 below were converted into their deprotonated, electrically neutral form by method A) and placed on a support, which was tested for sublimation or evaporation behavior by method B). Paper coated with polyester was used as the acceptor. The resulting color tone and the thermal transfer parameters T * and ΔE T are listed in the tables.
Figure imgb0012
Figure imgb0013
Figure imgb0014
Figure imgb0015

Die in den nachfolgenden Tabellen 3 und 4 genannten kationischen Farbstoffe wurden nach Methode A) in ihre deprotonierte, elektrisch neutrale Form übergeführt und auf einen Träger gebracht, dieser wurde nach Methode B) auf das Sublimations- oder Verdampfungsverhalten geprüft. Als Acceptor diente ein Papier mit sauer aktiviertem Clay als Beschichtungs­material. Der Transfer erfolgte hier während 30 sec bei einer Temperatur von 130°C.The cationic dyes mentioned in Tables 3 and 4 below were converted into their deprotonated, electrically neutral form by method A) and placed on a support, which was tested for sublimation or evaporation behavior by method B). A paper with acid-activated clay served as an acceptor as a coating material. The transfer took place here for 30 seconds at a temperature of 130 ° C.

Der in den Tabellen 3 und 4 aufgeführte Ausdruck "Abs" steht für Absorption. Die Absorption ist mit der Transmission Tra durch folgende Gleichung verknüpft: Abs = 1-Tra.

Figure imgb0016
Figure imgb0017
Figure imgb0018
Figure imgb0019
Figure imgb0020
Figure imgb0021
Figure imgb0022
 The expression "Abs" listed in Tables 3 and 4 stands for absorption. The absorption is linked to the transmission Tra by the following equation: Abs = 1-Tra.
Figure imgb0016
Figure imgb0017
Figure imgb0018
Figure imgb0019
Figure imgb0020
Figure imgb0021
Figure imgb0022

Die in der folgenden Tabelle 5 aufgeführten kationischen Farbstoffe wurden in ihrer deprotonierten, elektrisch neutralen Form unter den für Tabelle 1 gültigen Bedingungen übertragen.

Figure imgb0023
The cationic dyes listed in Table 5 below were transferred in their deprotonated, electrically neutral form under the conditions valid for Table 1.
Figure imgb0023

Änhliche Resultate wurden mit den in den Tabellen 6 und 7 genannten kationischen Farbstoffen bei Übertragung ihrer deprotonierten, elektrisch neutralen Form auf mit sauer aktiviertem Clay beschichtes Papier erzielt. Der resultierende Farbton ist jeweils angegeben.

Figure imgb0024
Figure imgb0025
Figure imgb0026
Figure imgb0027
 Similar results were obtained with the cationic dyes mentioned in Tables 6 and 7 when their deprotonated, electrically neutral form was transferred to paper coated with acid-activated clay. The resulting color is indicated in each case.
Figure imgb0024
Figure imgb0025
Figure imgb0026
Figure imgb0027

Claims (3)

1. Verfahren zur Übertragung von Farbstoffen von einem Träger auf einen Acceptor durch Sublimation oder Verdampfung der Farbstoffe mit Hilfe eines Thermokopfs, dadurch gekennzeichnet, daß man einen Träger verwendet, auf dem sich kationische Farbstoffe mit Cyaninchromophor, die mindestens eine N-H-Gruppierung aufweisen, die Bestandteil des Cyaninchromophors ist, in ihrer an der N-H-Gruppierung deprotonierten, elektrisch neutralen Form befinden, und diese deprotonierten Farb­stoffe auf ein beschichtetes Papier überträgt.1. A method for transferring dyes from a carrier to an acceptor by sublimation or evaporation of the dyes with the aid of a thermal head, characterized in that a carrier is used on which there are cationic dyes with cyanine chromophore which have at least one NH group which Part of the cyanine chromophore is in its electrically neutral form, which is deprotonated on the NH group, and transfers these deprotonated dyes to a coated paper. 2. Verfahren gemäß Anspruch 1, dadurch gekennzeichet, daß man kationische Farbstoffe, deren Kation die Formel I aufweist
Figure imgb0028
 in der
      R¹, R² und R⁷ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, C₁-C₄-Alkylthio, Halogen, Cyano, Hydroxy oder Phenyl substituiert ist, oder C₅-C₇-Cycloalkyl oder R¹ und R² zusammen mit dem sie verbindenden Stickstoffatom einen 5- oder 6-gliedrigen, gesättigten heterocyclischen Rest,
      R³ und R⁵ gleich oder verschieden sind und unabhängig voneinander jeweils Wasserstoff, C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen,
      R⁴ Wasserstoff oder zusammen mit R⁵ einen anellierten Benzoring,
      R⁶ Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch C₁-C₄-Alkoxy, C₁-C₄-Alkylthio, Halogen, Cyano, Hydroxy oder Phenyl substituiert ist, C₅-C₇-Cycloalkyl oder den Rest
Figure imgb0029
 in dem R⁸, R⁹ und R¹⁰ gleich oder verschieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen stehen, und
      A Sauerstoff oder Schwefel bedeuten, in ihrer deprotonierten, elektrisch neutralen Form überträgt.2. The method according to claim 1, characterized in that cationic dyes whose cation has the formula I.
Figure imgb0028
 in the
R¹, R² and R⁷ are the same or different and are each independently hydrogen, C₁-C₄-alkyl, which is optionally substituted by C₁-C₄-alkoxy, C₁-C₄-alkylthio, halogen, cyano, hydroxy or phenyl, or C₅-C₇ -Cycloalkyl or R¹ and R² together with the nitrogen atom connecting them a 5- or 6-membered, saturated heterocyclic radical,
R³ and R⁵ are the same or different and are each independently hydrogen, C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen,
R⁴ is hydrogen or, together with R⁵, a fused benzo ring,
R⁶ is hydrogen, C₁-C₄-alkyl, which is optionally substituted by C₁-C₄-alkoxy, C₁-C₄-alkylthio, halogen, cyano, hydroxy or phenyl, C₅-C₇-cycloalkyl or the rest
Figure imgb0029
 in which R⁸, R⁹ and R¹⁰ are the same or different and each independently represent hydrogen, C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen, and
A is oxygen or sulfur, in its deprotonated, electrically neutral form. 3. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß man kationische Farbstoffe, deren Kation die Formel II aufweist
Figure imgb0030
 in denen R¹⁴ für Wasserstoff, C₁-C₄-Alkyl,
das gegebenenfalls durch Halogen, Hydroxy oder C₁-C₄-Alkoxy substituiert ist, oder C₁-C₄-Alkoxy, R¹⁵ und R¹⁶ gleich oder ver­schieden sind und unabhängig voneinander jeweils für Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch Halogen, Hydroxy, C₁-C₄-Alkoxy oder Phenyl substituiert ist, oder gegebenenfalls durch C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen substituiertes Phenyl, W für Schwefel oder Di-C₁-C₄-Alkylmethylen und T für den Rest CH oder Stickstoff stehen,
      R¹² Wasserstoff, C₁-C₄-Alkyl, das gegebenenfalls durch Halogen oder C₁-C₄-Alkoxy substituiert ist, oder gegebenenfalls durch C₁-C₄-Alkyl, C₁-C₄-Alkoxy oder Halogen substituiertes Phenyl,
      R¹³ Wasserstoff oder C₁-C₄-Alkyl, das gegebenenfalls durch Halogen oder C₁-C₄-Alkoxy substituiert ist,
      X und Y gleich oder verschieden sind und unabhängig voneinander jeweils den Rest CH oder Stickstoff,
      Z den Rest
Figure imgb0031
 und
      m 0 oder 1 bedeuten, oder in der, falls m 1 ist,
die Gruppierung
Figure imgb0032
 steht, in denen
R¹³ und R¹⁵ jeweils die obengenannte Bedeutung besitzen, mit der Maßgabe, daß wenn m 0 ist, X und Y nicht gleichzeitig die Bedeutung von Stickstoff besitzen sollen, in ihrer deprotonierten, elektrisch neutralen Form überträgt.3. The method according to claim 1, characterized in that cationic dyes whose cation has the formula II
Figure imgb0030
 in which R¹⁴ represents hydrogen, C₁-C₄ alkyl,
which is optionally substituted by halogen, hydroxy or C₁-C₄-alkoxy, or C₁-C₄-alkoxy, R¹⁵ and R¹⁶ are the same or different and are each independently hydrogen, C₁-C₄-alkyl, optionally substituted by halogen, hydroxy, C₁ -C₄-alkoxy or phenyl is substituted, or phenyl optionally substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen, W is sulfur or di-C₁-C₄-alkylmethylene and T is CH or nitrogen,
R¹² is hydrogen, C₁-C₄-alkyl, which is optionally substituted by halogen or C₁-C₄-alkoxy, or phenyl which is optionally substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy or halogen,
R¹³ is hydrogen or C₁-C₄-alkyl, which is optionally substituted by halogen or C₁-C₄-alkoxy,
X and Y are the same or different and each independently the radical CH or nitrogen,
Z the rest
Figure imgb0031
 and
m is 0 or 1, or in which, if m is 1,
the grouping
Figure imgb0032
 stands in which
R¹³ and R¹⁵ each have the meaning given above, with the proviso that when m is 0, X and Y should not simultaneously have the meaning of nitrogen, in their deprotonated, electrically neutral form.
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* Cited by examiner, † Cited by third party
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EP0498267A1 (en) * 1991-01-30 1992-08-12 Sony Corporation Dye and dye carrier ink ribbon for thermal dye transfer hard copy
EP0506034A1 (en) * 1991-03-28 1992-09-30 Sony Corporation Image-forming method, and an ink ribbon and a printing sheet used for the method
EP0611663A1 (en) * 1993-01-20 1994-08-24 Agfa-Gevaert N.V. Heterocyclic hydrazonedyes and dye-donor elements containing the same for use in thermal dye transfer
EP0747231A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer system with low-Tg polymeric receiver containing an acid moiety
EP0747233A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer assembly with polyester ionomer receiver
EP0747236A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer system with a dye-receiving element containing an acid generator
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EP0747231A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer system with low-Tg polymeric receiver containing an acid moiety
EP0747233A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer assembly with polyester ionomer receiver
EP0747236A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer system with a dye-receiving element containing an acid generator
EP0747232A1 (en) * 1995-06-06 1996-12-11 Eastman Kodak Company Thermal dye transfer system with receiver containing an acid moiety
WO2011114137A1 (en) * 2010-03-17 2011-09-22 Pharmalucia Limited Toluidine blue derivatives as photosensitising compounds

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US4880769A (en) 1989-11-14
EP0273307B1 (en) 1992-06-10
DE3779741D1 (en) 1992-07-16
DE3644369A1 (en) 1988-07-07
JP2731906B2 (en) 1998-03-25
EP0273307A3 (en) 1989-11-08
JPS63173692A (en) 1988-07-18

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