EP0955183B1 - Thermal transfer ribbon - Google Patents

Thermal transfer ribbon Download PDF

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Publication number
EP0955183B1
EP0955183B1 EP99108565A EP99108565A EP0955183B1 EP 0955183 B1 EP0955183 B1 EP 0955183B1 EP 99108565 A EP99108565 A EP 99108565A EP 99108565 A EP99108565 A EP 99108565A EP 0955183 B1 EP0955183 B1 EP 0955183B1
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EP
European Patent Office
Prior art keywords
thermal transfer
layer
wax
transfer ribbon
waxes
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Expired - Lifetime
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EP99108565A
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German (de)
French (fr)
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EP0955183A3 (en
EP0955183A2 (en
Inventor
Heinrich Krauter
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Pelikan Produktions AG
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Pelikan Produktions AG
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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
    • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
    • B41M5/42—Intermediate, backcoat, or covering layers
    • B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/382—Contact thermal transfer or sublimation processes
    • B41M5/392—Additives, other than colour forming substances, dyes or pigments, e.g. sensitisers, transfer promoting agents

Definitions

  • the invention relates to a thermal transfer ribbon with a conventional carrier, with a wax-bonded layer of thermal transfer ink formed on one side of the support and with a layer between the carrier and the wax-bound layer resin-bound separating layer.
  • a thermal transfer ribbon of the type described above goes from DE 195 48 033 A1 out.
  • the resin-bound separating layer described therein serves for better separation the wax-bound layer of thermal transfer ink from the respective carrier.
  • a particular goal of this well-known teaching is the need for training a so-called "top coat" (adhesive layer) or a two-layer thermal transfer ink exclude and satisfactory matte prints when thermal printing to obtain. This is ensured by the fact that both the resin-bound Separating layer as well as the wax-bound layer of thermal transfer ink in one contain a sufficiently large amount of a wax-soluble polymer.
  • the thermal transfer ribbon described above is highly suitable, the one mentioned Satisfying objectives. However, it is too with other objectives improve. This is especially true for thermal transfer printing on uncoated Paper ("plain paper”) that has a comparatively high roughness.
  • uncoated Paper plain paper
  • Paint application, low paint viscosity and low paint adhesion to the interface Paint Layer
  • Prior art products also show that print quality undesirably varied with "cold” and "hot” printheads.
  • the invention was therefore based on the object of a thermal transfer ribbon at the beginning to propose the type with which the above-mentioned objectives for Improvement of print quality, especially with "cold” or “hot” printing, especially on uncoated paper with high roughness.
  • this object is achieved in that at least the resin-bound Separating layer A) contains a wax-soluble polymer and the wax-bound Layer B) of thermal transfer ink 0 contains up to 1.5 wt .-% wax-soluble polymer, the waxes of the wax-bound Layer B) tightly cut waxes close together Freezing points are. Accordingly, preferably contains the wax-bound Layer B no significant amounts of wax-soluble polymer, in particular less than about 0.5% by weight.
  • a separation layer or release layer is used in the present field Layer understood that the transfer of the thermal transfer ink on the printing process controls the receiving substrate, but does not itself transfer to the substrate becomes.
  • a separating layer does not melt during the printing process, but softens at most and also has high adhesion to the wearer.
  • An essential aspect in solving the described task is the use "closely cut" waxes in the wax-bound layer, i.e. the melting and The solidification point of the waxes must lie close together.
  • the temperature difference between melting point and solidification point is preferably less here than about 10 ° C, especially less than about 7 ° C, and most preferred less than about 5 ° C.
  • wax-bound layer B of the thermal transfer ink
  • the waxes used follow the usual wax definition with the above restriction on tightly cut waxes. It will be particularly within the scope of the invention Waxes with a melting point of about 75 to 90 ° C are used. It deals In the broadest sense, it is a material that is solid to fragile hard, coarse to fine crystalline, translucent to opaque, but not glassy, above about 70 ° C melts, albeit at a relatively low viscosity just above the melting point and is not stringy. Waxes of this kind are natural waxes, assigned to chemically modified waxes and synthetic waxes.
  • Vegetable waxes in the form of natural waxes are particularly preferred of carnauba wax, candelilla wax, mineral waxes in the form of higher melting Ceresin and higher melting ozokerite (earth wax), petrochemical waxes, such as petrolatum, paraffin waxes and micro waxes.
  • chemically modified Waxes are especially montan ester waxes, hydrogenated castor oil and hydrogenated jojoba oil is preferred.
  • the synthetic waxes are polyalkylene waxes and polyethylene glycol waxes and therefrom by oxidation and / or Products manufactured by esterification are preferred. Amide waxes can also be used. In particular, modified microcrystalline waxes are particularly preferred here specify.
  • the framework of the melting point to be observed according to the invention for the used Waxing is critical. If the value falls below 70 ° C, then means this is that the mechanical anchoring is insufficient and thus color transfer and color resolution are not satisfactory. Melting points higher than about 95 ° C lead disadvantageously to an increased energy expenditure during the printing process.
  • a good example of a wax that can be used according to the invention is carnauba wax, whose melting point is around 85 ° C and its solidification point is around 78 ° C.
  • the waxes indicated result in a desirably low level during the printing process Thermal transfer ink cohesion.
  • the wax materials of the wax-bound thermal transfer ink can be varied Additives are incorporated, such as, in particular, tackifiers in the form of terpene phenolic resins (such as the commercial products Zonataclite 85 from Arizona Chemical) and hydrocarbon resins (such as the commercial products KW-Harz 61 B1 / 105 from VFT, Frankfurt).
  • An adhesive layer can be applied to layer B) Tackifier applied.
  • the coloring can be done by any colorant. It can be pigments, such as especially carbon black, but also solvent and / or binder soluble Colorants such as the commercial product Basoprint, organic color pigments and various Trade azo dyes (Cerces and Sudan dyes). Soot applies in the frame of the present invention as particularly suitable.
  • the thermal transfer ink preferably contains the colorant, in particular color pigment, in an amount of about 5 to 20% by weight.
  • the melting point of the wax-bound thermal transfer ink is generally between about 60 and 80 ° C.
  • the thermal transfer color of the above-mentioned layer B) of the invention Thermal transfer ribbon, optionally with the additives described above preferably a viscosity, determined with the Rheomat 30 rotary viscometer Rheograph (principle: rotary viscometer, see Bulletin T 304d-7605 from Contraves AG Zurich / CH) at a temperature of 100 ° C of about 50 to 150 mPa • s, especially from 70 to 120 mPa • s. Falling below the value of about 50 mPa • s leads to blurring ("spreading"). When the value exceeds 250 mPa • s, the desired resolution may deteriorate.
  • a central feature of the thermal transfer ribbon according to the invention is that that a wax-soluble polymer is mainly contained in layer A).
  • Wax soluble is understood here to mean that this polymer is in a liquid wax Shows solubility. These are not necessarily “real solutions”, but mostly stable dispersions. This leads to cooling such a solution of the polymer in wax no phase separation occurs or this polymer is compatible with the wax.
  • the melt index MFI is 25 up to 1000 g / 10 min (220 ° C / 2.16 kg), preferably at 400 to 800 g / 10 min (DIN 53735 / ISO 1133, sh. also Römpp-Chemie Lexikon, volume 5, 9th edition, p. 4036, r. Sp.).
  • Wax-soluble polymers in the sense of the invention are characterized in that they melt below about 100 ° C and show stickiness in the molten state.
  • Suitable polymers are e.g. Ethylene-vinyl acetate copolymers, polyamides, Ethylene-alkyl acrylate copolymer, ethylene-acrylic acid copolymers, polyvinyl ether, and polyisobutene and ionomer resins. Of these, ethylene-acrylic acid copolymers are particularly preferred and ethylene vinyl acetate copolymers (EVA).
  • ethylene-vinyl acetate copolymers is used to increase the adhesion between the separation layer A) and the layer B) have a vinyl acetate content of about 16 to 42, in particular about 18 to 40% by weight is preferred.
  • the melt index MFI (according to DIN 53735) of the ethylene-vinyl acetate copolymer should last for about 20 g / 10 min, especially about 30 g / 10 min (220 ° C / 2.16 kg). It preferably has Ethylene vinyl acetate copolymer to adjust low adhesion between the separating layer A) and the layer B) have a vinyl acetate content of about 3 to 17, in particular about 6 to 12% by weight.
  • wax-soluble polymers also includes those that already exist Show a certain stickiness at room temperature, such as certain polyisobutenes with an oily, viscous to rubbery consistency. Such products are sold under the trade name Oppanol (BASF, Germany, see. Römpp Chemie Lexikon 9th ed., Vol. 4, pp. 3121/3122). To these at room temperature sticky wax-soluble polymers also include raw materials based of polyvinylethyl, methyl, and isobutyl ether, which are available under the trade name Lutonal are sold (BASF, Germany, see Römpp-Chemie Lexikon, 9. Ed., Vol. 3, p. 2566).
  • a special feature of the present invention is the relocation of the main quantity of the wax-soluble polymer under discussion from layer B) into the separating layer A).
  • the wax-soluble polymers can be used individually or as a mixture with one another be used.
  • the same or different wax-soluble polymers can be used.
  • the wax-soluble polymer preferably in an amount of contain about 10 to 60 wt .-%, in particular about 20 to 40 wt .-%. Will the Value below 10% by weight, then the adhesion to the ink layer is too high, and no homogeneous color transfer is guaranteed.
  • a value of more than 60 % By weight leads to insufficient adhesion to the paint layer and thus to poor resolution of the printed characters.
  • the transfer of the main amount of the wax-soluble polymer, in particular in the form of ethylene-vinyl acetate copolymer, from the thermal transfer ink into the separating layer causes a relatively low color viscosity even when using a large amount of ester wax (melting point ⁇ 80 ° C).
  • the lower viscosity and good soot dispersibility in ester waxes allow a higher concentration of pigment, especially soot, and thus lower paint application (g / m 2 ) with the same OD (optical density).
  • the separation layer A) containing the majority of wax-soluble polymers also fulfills the function of a "matt layer".
  • the matt layer leads to the fact that in the thermal printing process really matte prints are produced. This is because not only does the thermal transfer ink become liquid during the printing process and thus sticks to the substrate, especially in the form of a paper acceptor, but also the Release layer softens and retains a noticeable adhesion to the color layer, so that a completely flat transfer of, for example, print symbols to the paper acceptor not possible. Rather, the surface of the printed symbols slightly roughened, so that the surface of the symbol transferred as a result of Refraction / diffusion of light appears matt.
  • layer B) is black Pigment and the separation layer additionally contains carbon black, especially in an amount from about 20 to 50% by weight, which results in the written-off thermal transfer ribbon offers sufficient data protection.
  • the separating layer is preferably silica and dispersing agents. During the production of the layer, this leads to that the soot remains finely distributed in the layer and does not sediment out.
  • the separation layer A contains release agents in an amount of about 5 to 30 wt .-%., These being in the form of nonionic Surfactants, emulsifiers, polyethylene glycols, etc. are present.
  • the application thickness of the separating layer A) and the layer B) is not critical.
  • the separating layer A) preferably has an application thickness of approximately 0.2 to 5 g / m 2 , in particular approximately 1 to 3 g / m 2
  • the layer B) an application thickness of approximately 1.0 to 10 g / m 2 , in particular from about 3 to 6 g / m 2 .
  • the separating layer A) is a resin-bound layer, the resin binder preferably being a solid resin with a softening range in the range from about 70 to 200 ° C.
  • the resin preferably comprises an alkyd, epoxy, melamine, phenol, urethane and / or polyester or copolyester resin and / or a polyamide, hydrocarbon resin, natural resin, polyvinyl ether and / or polyisobutene.
  • the carrier of the ribbon according to the invention is not critical.
  • a base film for Thermal transfer ribbons are preferably polyethylene terephthalate foils (PETP) or capacitor papers used.
  • the selection parameters are as high as possible Tensile elongation values and thermal stability with low film thicknesses.
  • the PETP films are available down to about 2.5 ⁇ m, capacitor paper down to about 6 ⁇ m.
  • the thermal print head reaches temperatures of up to 400 ° C, i.e. Temperatures above the softening point of PETP. It recommends itself, when using PETP films on the back, which with the Thermal head comes into contact, a particularly resistant to heat Layer.
  • the coating material in this case preferably consists of paraffin, silicone, natural waxes, in particular carnauba wax, beeswax, ozokerite and paraffin wax, synthetic waxes, especially acid waxes, ester waxes, partially saponified ester waxes and Polyethylene waxes, glycols or polyglycol, antistatic agents and / or Surfactants. If such a rear-side coating is provided, then one takes place undisturbed heat transfer from the thermal print head to the thermal transfer ribbon the consequence that particularly sharp prints are achieved.
  • top coat adheresive layer approximately 0.5 to 0.7 g / m 2
  • wax-bonded layer of thermal transfer ink B. about 4.0 to 4.5 g / m 2
  • separating layer A about 0.5 to 1.0 g / m 2
  • thickness of the support e.g. polyethylene terephthalate
  • Non-stick layer about 0.05 to 0.1 g / m 2 .
  • the thermal transfer ribbon according to the invention described above can be varied Make way using standard application methods. For example by spraying or printing on a solution or dispersion, either with Water or an organic solvent as a dispersion or solvent, by application from the melt, which is particularly important for the wax-bound thermal transfer ink applies, or by normal application using a doctor blade in the form an aqueous suspension with finely divided material to be applied.
  • the following procedure has proven to be proved to be particularly advantageous: first, an aqueous one is applied in a thin layer Suspension of the starting materials of the separating layer applied to the carrier, the when the water evaporates, the separating layer A) is formed.
  • the thermal transfer ink can also be in the form of a melt Apply customary application technologies to the interface, for example with a squeegee.
  • the temperature of the respective melt should generally be about 100 to 130 ° C. After the application, the applied materials are left just cool down.
  • thermal transfer ink layer B about 1 to 10 g / m 2 , preferably about 3 to 6 g / m 2 , separating layer A) 0.2 to 5 g / m 2 , preferably about 0.5 to 1.5 g / m 2 , carrier film, in particular polyester film of a thickness of about 2 to 8 microns, in particular a thickness of about 4 to 5 microns, and the addressed back coating in an application thickness of about 0.01 to 0.2 g / m 2 , in particular from about 0.05 to 0.1 g / m 2 .

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

Description

Die Erfindung betrifft ein Thermotransferband mit einem üblichen Träger, mit einer auf einer Seite des Trägers ausgebildeten wachsgebundenen Schicht einer Thermotransferfarbe und mit einer sich zwischen Träger und wachsgebundener Schicht befindenden harzgebundenen Trennschicht.The invention relates to a thermal transfer ribbon with a conventional carrier, with a wax-bonded layer of thermal transfer ink formed on one side of the support and with a layer between the carrier and the wax-bound layer resin-bound separating layer.

Ein Thermotransferband der oben beschriebenen Art geht aus der DE 195 48 033 A1 hervor. Die darin beschriebene harzgebundene Trennschicht dient der besseren Trennung der wachsgebundenen Schicht der Thermotransferfarbe von dem jeweiligen Träger. Besonderes Ziel dieser bekannten Lehre ist es, die Notwendigkeit der Ausbildung einer sogenannten "Topcoat" (Haftschicht) bzw. einer zweischichtigen Thermotransferfarbe auszuschließen und beim Thermodruckvorgang zufriedenstellende matte Ausdrucke zu erhalten. Dies wird dadurch gewährleistet, daß sowohl die harzgebundene Trennschicht als auch die wachsgebundene Schicht der Thermotransferfarbe in einer ausreichend großen Menge ein wachslösliches Polymer enthalten. Bevorzugt ist es, daß die wachsgebundene Schicht der Thermotransferfarbe etwa 2 bis 20 Gew.-% wachslösliches Polymer enthält, insbesondere 5 bis 10 Gew.-%.A thermal transfer ribbon of the type described above goes from DE 195 48 033 A1 out. The resin-bound separating layer described therein serves for better separation the wax-bound layer of thermal transfer ink from the respective carrier. A particular goal of this well-known teaching is the need for training a so-called "top coat" (adhesive layer) or a two-layer thermal transfer ink exclude and satisfactory matte prints when thermal printing to obtain. This is ensured by the fact that both the resin-bound Separating layer as well as the wax-bound layer of thermal transfer ink in one contain a sufficiently large amount of a wax-soluble polymer. Prefers it is that the wax-bonded layer of thermal transfer ink is about 2 to 20 % By weight of wax-soluble polymer, in particular 5 to 10 Wt .-%.

Das oben beschriebene Thermotransferband ist in hohem Maße geeignet, der angesprochenen Zielsetzung zu genügen. Allerdings ist es bei anderen Zielsetzungen zu verbessern. Dies gilt insbesondere für den Thermotransfer-Druck auf nicht gestrichenem Papier ("Plain Paper"), das eine vergleichsweise hohe Rauhigkeit aufweist. Für gute Druckqualität und für Qualitätsprodukte sind die folgenden physikalischen Eigenschaften unabdingbar: Die Kraft der mechanischen Verankerung der Thermotransferfarbe auf dem bedruckten Papier muß während des Trennvorganges im Thermodrucker - Trennung Band von Papier - größer als die Kohäsion der Thermotransferfarbe selbst und die Adhäsion der Thermotransferfarbe zum Substrat sein, d.h. niedriger Farbauftrag, geringe Farbviskosität und geringe Adhäsion der Farbe zur Trennschicht ("Release-Layer") während des Druckvorgangs führen zu einer optimalen Druckqualität. Erzeugnisse des Standes der Technik zeigen darüber hinaus, daß die Druckqualität bei "kaltem" und "heißem" Druckkopf unerwünscht variiert.The thermal transfer ribbon described above is highly suitable, the one mentioned Satisfying objectives. However, it is too with other objectives improve. This is especially true for thermal transfer printing on uncoated Paper ("plain paper") that has a comparatively high roughness. For good print quality and for quality products are the following physical properties indispensable: the power of mechanically anchoring the thermal transfer ink on the printed paper during the separation process in the thermal printer - Separation tape from paper - greater than the cohesion of the thermal transfer ink itself and the adhesion of the thermal transfer ink to the substrate, i.e. lower Paint application, low paint viscosity and low paint adhesion to the interface ("Release Layer") during the printing process lead to an optimal print quality. Prior art products also show that print quality undesirably varied with "cold" and "hot" printheads.

Der Erfindung lag daher die Aufgabe zugrunde, ein Thermotransferband der eingang bezeichneten Art vorzuschlagen, mit dem die oben angesprochenen Ziele zur Verbesserung der Druckqualität, insbesondere bei "kaltem" bzw. "heißem" Druck, besonders auch auf ungestrichenem Papier hoher Rauhigkeit, erreicht werden.The invention was therefore based on the object of a thermal transfer ribbon at the beginning to propose the type with which the above-mentioned objectives for Improvement of print quality, especially with "cold" or "hot" printing, especially on uncoated paper with high roughness.

Erfindungsgemäß wird diese Aufgabe dadurch gelöst, daß zumindest die harzgebundene Trennschicht A) ein wachslösliches Polymer enthält und die wachsgebundene Schicht B) der Thermotransferfarbe 0 bis 1,5 Gew.-% wachslösliches Polymer enthält, wobei die Wachse der wachsgebundenen Schicht B) eng geschnittene Wachse dicht beieinanderliegender Schmelz- und Erstarrungspunkte sind. Vorzugsweise enthält demzufolge die wachsgebundene Schicht B keine wesentlichen Mengen an wachslöslichen Polymer, insbesondere weniger als etwa 0,5 Gew.-%.According to the invention, this object is achieved in that at least the resin-bound Separating layer A) contains a wax-soluble polymer and the wax-bound Layer B) of thermal transfer ink 0 contains up to 1.5 wt .-% wax-soluble polymer, the waxes of the wax-bound Layer B) tightly cut waxes close together Freezing points are. Accordingly, preferably contains the wax-bound Layer B no significant amounts of wax-soluble polymer, in particular less than about 0.5% by weight.

Unter einer Trennschicht bzw. Releaseschicht wird im vorliegenden Fachgebiet eine Schicht verstanden, die beim Druckvorgang die Abgabe der Thermotransferfarbe auf das aufnehmende Substrat steuert, selbst jedoch nicht auf das Substrat übertragen wird. Eine Trennschicht schmilzt beim Druckvorgang nicht, sondern erweicht allenfalls und weist außerdem eine hohe Adhäsion zum Träger auf.A separation layer or release layer is used in the present field Layer understood that the transfer of the thermal transfer ink on the printing process controls the receiving substrate, but does not itself transfer to the substrate becomes. A separating layer does not melt during the printing process, but softens at most and also has high adhesion to the wearer.

Ein wesentlicher Gesichtspunkt bei der Lösung der bezeichneten Aufgabe ist der Einsatz "eng geschnittener" Wachse in der wachsgebundenen Schicht, d.h. der Schmelzund Erstarrungspunkt der Wachse müssen dicht zusammen liegen. Die Temperaturdifferenz zwischen Schmelz- und Erstarrungspunkt beträgt hier vorzugsweise weniger als etwa 10°C, insbesondere weniger als etwa 7°C und ganz besonders bevorzugt weniger als etwa 5°C.An essential aspect in solving the described task is the use "closely cut" waxes in the wax-bound layer, i.e. the melting and The solidification point of the waxes must lie close together. The temperature difference between melting point and solidification point is preferably less here than about 10 ° C, especially less than about 7 ° C, and most preferred less than about 5 ° C.

Die im Rahmen der Erfindung in der wachsgebundenen Schicht B) der Thermotransferfarbe eingesetzten Wachse folgen der üblichen Wachsdefinition mit der obigen Einschränkung auf eng geschnittene Wachse. Es werden im Rahmen der Erfindung insbesondere Wachse eines Schmelzpunktes von etwa 75 bis 90°C eingesetzt. Es handelt sich also im weitesten Sinne um ein Material, das fest bis brüchig hart, grob bis feinkristallin, durchscheinend bis opak, jedoch nicht glasartig ist, oberhalb etwa 70°C schmilzt, allerdings schon wenig oberhalb des Schmelzpunktes verhältnismäßig niedrigviskos und nicht fadenziehend ist. Wachse dieser Art sind den natürlichen Wachsen, chemisch-modifizierten Wachsen und den synthetischen Wachsen zuzuordnen. Besonders bevorzugt sind unter den natürlichen Wachsen pflanzliche Wachse in Form von Carnaubawachs, Candelillawachs, Mineralwachse in Form von höherschmelzendem Ceresin und höherschmelzendem Ozokerit (Erdwachs), petrochemische Wachse, wie beispielsweise Petrolatum, Paraffinwachse und Mikrowachse. Unter den chemisch-modifizierten Wachsen sind insbesondere Montanesterwachse, hydriertes Rizinusöl und hydriertes Jojobaöl bevorzugt. Unter den synthetischen Wachsen sind Polyalkylenwachse und Polyethylenglykolwachse sowie daraus durch Oxidation und/oder Veresterung hergestellte Produkte bevorzugt. Amidwachse sind ebenfalls verwendbar. Im einzelnen sind hier als besonders bevorzugt modifizierte mikrokristalline Wachse anzugeben.In the context of the invention in the wax-bound layer B) of the thermal transfer ink The waxes used follow the usual wax definition with the above restriction on tightly cut waxes. It will be particularly within the scope of the invention Waxes with a melting point of about 75 to 90 ° C are used. It deals In the broadest sense, it is a material that is solid to fragile hard, coarse to fine crystalline, translucent to opaque, but not glassy, above about 70 ° C melts, albeit at a relatively low viscosity just above the melting point and is not stringy. Waxes of this kind are natural waxes, assigned to chemically modified waxes and synthetic waxes. Vegetable waxes in the form of natural waxes are particularly preferred of carnauba wax, candelilla wax, mineral waxes in the form of higher melting Ceresin and higher melting ozokerite (earth wax), petrochemical waxes, such as petrolatum, paraffin waxes and micro waxes. Among the chemically modified Waxes are especially montan ester waxes, hydrogenated castor oil and hydrogenated jojoba oil is preferred. Among the synthetic waxes are polyalkylene waxes and polyethylene glycol waxes and therefrom by oxidation and / or Products manufactured by esterification are preferred. Amide waxes can also be used. In particular, modified microcrystalline waxes are particularly preferred here specify.

Der erfindungsgemäß einzuhaltende Rahmen des Schmelzpunktes für die herangezogenen Wachse ist kritisch. Wird der Wert von 70°C unterschritten, dann bedeutet dies, daß die mechanische Verankerung nicht ausreichend ist und somit Farbtransfer und Farbauflösung nicht zufriedenstellen. Höhere Schmelzpunkte als etwa 95°C führen nachteiligerweise zu einem erhöhten Energieaufwand beim Druckvorgang.The framework of the melting point to be observed according to the invention for the used Waxing is critical. If the value falls below 70 ° C, then means this is that the mechanical anchoring is insufficient and thus color transfer and color resolution are not satisfactory. Melting points higher than about 95 ° C lead disadvantageously to an increased energy expenditure during the printing process.

Ein gutes Beispiel für ein erfindungsgemäß einsetzbares Wachs ist Carnaubawachs, dessen Schmelzpunkt bei etwa 85°C und dessen Erstarrungspunkt bei etwa 78°C liegt. A good example of a wax that can be used according to the invention is carnauba wax, whose melting point is around 85 ° C and its solidification point is around 78 ° C.

Die bezeichneten Wachse führen beim Druckvorgang zu einer wünschenswert niedrigen Kohäsion der Thermotransferfarbe.The waxes indicated result in a desirably low level during the printing process Thermal transfer ink cohesion.

Den Wachsmaterialien der wachsgebundenen Thermotransferfarbe können vielfältige Zusätze einverleibt werden, wie insbesondere Klebrigmacher in Form von Terpenphenolharzen (wie z.B. die Handelsprodukte Zonataclite 85 von der Firma Arizona Chemical) und Kohlenwasserstoffharzen (wie z.B. die Handelsprodukte KW-Harz 61 B1/105 von der Firma VFT, Frankfurt). Auf die Schicht B) kann eine Haftschicht mit Klebrigmacher aufgetragen sein. In einer Ausführungsform befindet sich auf der Schicht B) eine Haftschicht, insbesondere eine Paraffinschicht mit einem Gehalt an feinverteiltem klebrigmachenden Kohlenwasserstoffharz, wobei das Paraffin einen Schmelzpunkt von insbesondere etwa 60 bis 95°C aufweist.The wax materials of the wax-bound thermal transfer ink can be varied Additives are incorporated, such as, in particular, tackifiers in the form of terpene phenolic resins (such as the commercial products Zonataclite 85 from Arizona Chemical) and hydrocarbon resins (such as the commercial products KW-Harz 61 B1 / 105 from VFT, Frankfurt). An adhesive layer can be applied to layer B) Tackifier applied. In one embodiment, is on the Layer B) an adhesive layer, in particular a paraffin layer containing finely divided tackifying hydrocarbon resin, the paraffin having a Has a melting point of in particular about 60 to 95 ° C.

Die Einfärbung kann durch beliebige Farbmittel erfolgen. Es kann sich um Pigmente, wie insbesondere um Ruß, aber auch um lösungsmittel- und/oder bindemittellösliche Farbmittel, wie das Handelsprodukt Basoprint, organische Farbpigmente sowie verschiedene Azofarbstoffe (Cerces- und Sudanfarbstoffe) handeln. Ruß gilt im Rahmen der vorliegenden Erfindung als besonders geeignet. Vorzugsweise enthält die Thermotransferfarbe das Farbmittel, insbesondere Farbpigment, in einer Menge von etwa 5 bis 20 Gew.-%. Der Schmelzpunkt der wachsgebundenen Thermotransferfarbe liegt im allgemeinen zwischen etwa 60 und 80°C.The coloring can be done by any colorant. It can be pigments, such as especially carbon black, but also solvent and / or binder soluble Colorants such as the commercial product Basoprint, organic color pigments and various Trade azo dyes (Cerces and Sudan dyes). Soot applies in the frame of the present invention as particularly suitable. The thermal transfer ink preferably contains the colorant, in particular color pigment, in an amount of about 5 to 20% by weight. The melting point of the wax-bound thermal transfer ink is generally between about 60 and 80 ° C.

Die Thermotransferfarbe der oben bezeichneten Schicht B) des erfindungsgemäßen Thermotransferbandes, gegebenenfalls mit den vorstehend bezeichneten Zusätzen, hat vorzugsweise eine Viskosität, bestimmt mit dem Rotationsviskometer Rheomat 30 mit Rheograph (Prinzip: Rotationsviskometer, sh. Bulletin T 304d-7605 der Firma Contraves AG Zürich / CH) bei einer Temperatur von 100°C von etwa 50 bis 150 mPa•s, insbesondere von 70 bis 120 mPa•s. Das Unterschreiten des Wertes von etwa 50 mPa•s führt zu Unschärfe ("spreading"). Mit dem Überschreiten des Wertes von 250 mPa•s kann die gewünschte Auflösung verschlechtert werden. The thermal transfer color of the above-mentioned layer B) of the invention Thermal transfer ribbon, optionally with the additives described above preferably a viscosity, determined with the Rheomat 30 rotary viscometer Rheograph (principle: rotary viscometer, see Bulletin T 304d-7605 from Contraves AG Zurich / CH) at a temperature of 100 ° C of about 50 to 150 mPa • s, especially from 70 to 120 mPa • s. Falling below the value of about 50 mPa • s leads to blurring ("spreading"). When the value exceeds 250 mPa • s, the desired resolution may deteriorate.

Ein zentrales Merkmal des erfindungsgemäßen Thermotransferbandes besteht darin, daß hauptsächlich in Schicht A) ein wachslösliches Polymer enthalten ist. Unter "wachslöslich" wird hier verstanden, daß dieses Polymer in einem flüssigen Wachs Löslichkeit zeigt. Hierbei handelt es sich nicht notwendigerweise um "echte Lösungen", sondern meist um stabile Dispersionen. Dies führt dazu, daß beim Abkühlen einer derartigen Lösung des Polymers in Wachs keine Phasentrennung auftritt bzw. dieses Polymer mit dem Wachs verträglich ist. Der Schmelzindex MFI liegt bei 25 bis 1000 g/10 min (220°C / 2,16 kg), vorzugsweise bei 400 bis 800 g/10 min (DIN 53735 / ISO 1133, sh. auch Römpp-Chemie Lexikon, Band 5, 9. Aufl., S. 4036, r. Sp.). Wachslösliche Polymere im Sinne der Erfindung zeichnen sich dadurch aus, daß sie unterhalb etwa 100°C schmelzen und in geschmolzenem Zustand Klebrigkeit zeigen. Geeignete Polymere sind z.B. Ethylen-Vinylacetat-Copolymere, Polyamide, Ethylen-Alkylacrylat-Copolymer, Ethylen-Acrylsäure-Copolymere, Polyvinylether, und Polyisobuten sowie Ionomerharze. Hiervon sind besonders bevorzugt Ethylen-Acrylsäure-Copolymere und Ethylen-Vinylacetat-Copolymere (EVA). Bei Verwendung von Ethylen-Vinylacetat-Copolymeren ist zur Steigerung der Adhäsion zwischen der Trennschicht A) und der Schicht B) ein Vinylacetatgehalt von etwa 16 bis 42, insbesondere etwa 18 bis 40 Gew.-% bevorzugt. Der Schmelzindex MFI (nach DIN 53735) des Ethylen-Vinylacetat-Copolymers sollte über etwa 20 g/10 min, insbesondere über etwa 30 g/10 min (220°C / 2,16 kg) liegen. Bevorzugt besitzt das Ethylen-Vinylacetat-Copolymer zur Einstellung einer niedrigen Adhäsion zwischen der Trennschicht A) und der Schicht B) einen Vinylacetatgehalt von etwa 3 bis 17, insbesondere etwa 6 bis 12 Gew.-%.A central feature of the thermal transfer ribbon according to the invention is that that a wax-soluble polymer is mainly contained in layer A). Under "Wax soluble" is understood here to mean that this polymer is in a liquid wax Shows solubility. These are not necessarily "real solutions", but mostly stable dispersions. This leads to cooling such a solution of the polymer in wax no phase separation occurs or this polymer is compatible with the wax. The melt index MFI is 25 up to 1000 g / 10 min (220 ° C / 2.16 kg), preferably at 400 to 800 g / 10 min (DIN 53735 / ISO 1133, sh. also Römpp-Chemie Lexikon, volume 5, 9th edition, p. 4036, r. Sp.). Wax-soluble polymers in the sense of the invention are characterized in that they melt below about 100 ° C and show stickiness in the molten state. Suitable polymers are e.g. Ethylene-vinyl acetate copolymers, polyamides, Ethylene-alkyl acrylate copolymer, ethylene-acrylic acid copolymers, polyvinyl ether, and polyisobutene and ionomer resins. Of these, ethylene-acrylic acid copolymers are particularly preferred and ethylene vinyl acetate copolymers (EVA). Using of ethylene-vinyl acetate copolymers is used to increase the adhesion between the separation layer A) and the layer B) have a vinyl acetate content of about 16 to 42, in particular about 18 to 40% by weight is preferred. The melt index MFI (according to DIN 53735) of the ethylene-vinyl acetate copolymer should last for about 20 g / 10 min, especially about 30 g / 10 min (220 ° C / 2.16 kg). It preferably has Ethylene vinyl acetate copolymer to adjust low adhesion between the separating layer A) and the layer B) have a vinyl acetate content of about 3 to 17, in particular about 6 to 12% by weight.

Unter den Begriff "wachslösliche Polymere" fallen auch solche, die bereits bei Raumtemperatur eine gewisse Klebrigkeit zeigen, wie beispielsweise bestimmte Polyisobutene mit öliger, zähklebriger bis kautschukartiger Konsistenz. Derartige Produkte werden unter der Handelsbezeichnung Oppanol vertrieben (BASF, Deutschland, vgl. Römpp Chemie Lexikon 9. Aufl., Bd. 4, S. 3121/3122). Zu diesen bei Raumtemperatur klebrigen wachslöslichen Polymeren zählen auch Rohstoffe auf der Basis von Polyvinylethyl-, methyl-, und -isobutylether, die unter der Handelsbezeichnung Lutonal vertrieben werden (BASF, Deutschland, vgl. Römpp-Chemie Lexikon, 9. Aufl, Bd. 3, S. 2566).The term "wax-soluble polymers" also includes those that already exist Show a certain stickiness at room temperature, such as certain polyisobutenes with an oily, viscous to rubbery consistency. Such products are sold under the trade name Oppanol (BASF, Germany, see. Römpp Chemie Lexikon 9th ed., Vol. 4, pp. 3121/3122). To these at room temperature sticky wax-soluble polymers also include raw materials based of polyvinylethyl, methyl, and isobutyl ether, which are available under the trade name Lutonal are sold (BASF, Germany, see Römpp-Chemie Lexikon, 9. Ed., Vol. 3, p. 2566).

Besonderes Kennzeichen der vorliegenden Erfindung ist die Verlagerung der Hauptmenge des erörterten wachslöslichen Polymers aus der Schicht B) in die Trennschicht A). Die wachslöslichen Polymere können einzeln oder in Mischung untereinander verwendet werden. In der Trennschicht A) und, wenn vorhanden, in der Schicht B) können gleiche oder unterschiedliche wachslösliche Polymere verwendet werden. In der Trennschicht A) ist das wachslösliche Polymer vorzugsweise in einer Menge von etwa 10 bis 60 Gew.-%, insbesondere etwa 20 bis 40 Gew.-% enthalten. Wird der Wert von 10 Gew.-% unterschritten, dann ist die Adhäsion zur Farbschicht zu hoch, und es ist kein homogener Farbtransfer gewährleistet. Ein Wert von mehr als 60 Gew.-% führt zu einer nicht ausreichenden Adhäsion zur Farbschicht und somit zu einer schlechten Auflösung der abgedruckten Schriftzeichen.A special feature of the present invention is the relocation of the main quantity of the wax-soluble polymer under discussion from layer B) into the separating layer A). The wax-soluble polymers can be used individually or as a mixture with one another be used. In the separation layer A) and, if present, in layer B) the same or different wax-soluble polymers can be used. In the separation layer A) is the wax-soluble polymer preferably in an amount of contain about 10 to 60 wt .-%, in particular about 20 to 40 wt .-%. Will the Value below 10% by weight, then the adhesion to the ink layer is too high, and no homogeneous color transfer is guaranteed. A value of more than 60 % By weight leads to insufficient adhesion to the paint layer and thus to poor resolution of the printed characters.

Die Verlagerung der Hauptmenge des wachslöslichen Polymers, insbesondere in Form von Ethylen-Vinylacetat-Copolymer, aus der Thermotransferfarbe in die Trennschicht bewirkt sogar bei Einsatz von sehr viel Esterwachs (Schmelzpunkt ≥ 80°C) eine relativ niedrige Farbviskosität. Die somit niedrigere Viskosität und gute Rußdispergierbarkeit in Esterwachsen erlaubt eine höhere Konzentration an Pigment, insbesondere Ruß, und somit geringeren Farbauftrag (g/m2) bei gleicher OD (optische Dichte).The transfer of the main amount of the wax-soluble polymer, in particular in the form of ethylene-vinyl acetate copolymer, from the thermal transfer ink into the separating layer causes a relatively low color viscosity even when using a large amount of ester wax (melting point ≥ 80 ° C). The lower viscosity and good soot dispersibility in ester waxes allow a higher concentration of pigment, especially soot, and thus lower paint application (g / m 2 ) with the same OD (optical density).

Die den Hauptanteil wachslöslicher Polymere enthaltende Trennschicht A) erfüllt auch die Funktion einer "Mattschicht". Die Mattschicht führt dazu, daß beim Thermodruckvorgang wirklich matte Ausdrucke erzeugt werden. Dies beruht darauf, daß während des Druckvorgangs nicht nur die Thermotransferfarbe flüssig wird und somit am Substrat, insbesondere in Form eines Papierakzeptors anklebt, sondern auch die Trennschicht erweicht und eine merkliche Adhäsion zu der Farbschicht behält, so daß eine vollständig flächige Übertragung von beispielsweise Drucksymbolen auf den Papierakzeptor nicht möglich ist. Vielmehr wird die Oberfläche der abgedruckten Symbole etwas aufgerauht, so daß die Oberfläche des übertragenen Symbols in Folge von Lichtbrechung/Lichtdiffusion matt erscheint.The separation layer A) containing the majority of wax-soluble polymers also fulfills the function of a "matt layer". The matt layer leads to the fact that in the thermal printing process really matte prints are produced. This is because not only does the thermal transfer ink become liquid during the printing process and thus sticks to the substrate, especially in the form of a paper acceptor, but also the Release layer softens and retains a noticeable adhesion to the color layer, so that a completely flat transfer of, for example, print symbols to the paper acceptor not possible. Rather, the surface of the printed symbols slightly roughened, so that the surface of the symbol transferred as a result of Refraction / diffusion of light appears matt.

Der Mattierungseffekt wird weiter begünstigt, wenn die Schicht B) ein schwarzes Pigment und die Trennschicht zusätzlich Ruß enthält, insbesondere in einer Menge von etwa 20 bis 50 Gew.-%, was dazu führt, daß das abgeschriebene Thermotransferband einen ausreichenden Datenschutz bietet. Bei dieser vorteilhaften Ausgestaltung der vorliegenden Erfindung werden der Trennschicht vorzugsweise noch Kieselsäure und Dispergierhilfsmittel einverleibt. Dies führt bei der Herstellung der Schicht dazu, daß der Ruß fein in der Schicht verteilt bleibt und nicht aussedimentiert.The matting effect is further enhanced if layer B) is black Pigment and the separation layer additionally contains carbon black, especially in an amount from about 20 to 50% by weight, which results in the written-off thermal transfer ribbon offers sufficient data protection. In this advantageous embodiment In the present invention, the separating layer is preferably silica and dispersing agents. During the production of the layer, this leads to that the soot remains finely distributed in the layer and does not sediment out.

In einer weiteren Ausführungsform kann durch Zusatz von z.B. Polyätheralkoholen zur Trennschicht A das "Druckgeräusch" (Trennung des Bandes vom Papier nach dem Druckvorgang) gesteuert werden. Hierfür enthält die Trennschicht A) Trennmittel in einer Menge von etwa 5 bis 30 Gew.-%., wobei diese in Form von nichtionischen Tensiden, Emulgatoren, Polyäthylenglykolen usw. vorliegen.In a further embodiment, by adding e.g. Polyätheralkoholen to the separating layer A the "printing noise" (separation of the tape from the paper after the Printing process) can be controlled. For this purpose, the separation layer A) contains release agents in an amount of about 5 to 30 wt .-%., These being in the form of nonionic Surfactants, emulsifiers, polyethylene glycols, etc. are present.

Die Auftragsstärke der Trennschicht A) und der Schicht B) ist nicht kritisch. Vorzugsweise weist die Trennschicht A) eine Auftragsstärke von etwa 0,2 bis 5 g/m2, insbesondere etwa 1 bis 3 g/m2, und die Schicht B) eine Auftragsstärke von etwa 1,0 bis 10 g/m2, insbesondere von etwa 3 bis 6 g/m2 auf. Bei der Trennschicht A) handelt es sich um eine harzgebundene Schicht, wobei das Harzbindemittel vorzugsweise ein Festharz eines Erweichungsbereiches in dem Rahmen von etwa 70 bis 200°C ist. Vorzugsweise umfaßt das Harz ein Alkyd-, Epoxid-, Melamin-, Phenol-, Urethanund/oder Polyester- bzw. Copolyester-Harze und/oder ein Polyamid, Kohlenwasserstoffharz, natürliches Harz, Polyvinylether und/oder Polyisobuten.The application thickness of the separating layer A) and the layer B) is not critical. The separating layer A) preferably has an application thickness of approximately 0.2 to 5 g / m 2 , in particular approximately 1 to 3 g / m 2 , and the layer B) an application thickness of approximately 1.0 to 10 g / m 2 , in particular from about 3 to 6 g / m 2 . The separating layer A) is a resin-bound layer, the resin binder preferably being a solid resin with a softening range in the range from about 70 to 200 ° C. The resin preferably comprises an alkyd, epoxy, melamine, phenol, urethane and / or polyester or copolyester resin and / or a polyamide, hydrocarbon resin, natural resin, polyvinyl ether and / or polyisobutene.

Der Träger des erfindungsgemäßen Farbbandes ist nicht kritisch. Als Basisfolie fiir Thermotransferbänder werden vorzugsweise Polyethylentherephthalatfolien (PETP) oder Kondensatorpapiere verwendet. Die Auswahlparameter sind möglichst hohe Zugdehnungswerte und thermische Stabilität bei geringen Foliendicken. Die PETP-Folien sind bis etwa 2,5 µm, Kondensatorpapier bis etwa 6 µm herunter erhältlich. Beim Druckvorgang erreicht der Thermodruckkopf Temperaturen von bis zu 400°C, d.h. Temperaturen, die oberhalb des Erweichungspunktes von PETP liegen. Es empfiehlt sich, bei Verwendung von PETP-Folien auf deren Rückseite, die mit dem Thermokopf in Berührung kommt, eine gegen Hitze besonders widerstandsfähige Schicht vorzusehen.The carrier of the ribbon according to the invention is not critical. As a base film for Thermal transfer ribbons are preferably polyethylene terephthalate foils (PETP) or capacitor papers used. The selection parameters are as high as possible Tensile elongation values and thermal stability with low film thicknesses. The PETP films are available down to about 2.5 µm, capacitor paper down to about 6 µm. During the printing process, the thermal print head reaches temperatures of up to 400 ° C, i.e. Temperatures above the softening point of PETP. It recommends itself, when using PETP films on the back, which with the Thermal head comes into contact, a particularly resistant to heat Layer.

Eine vorteilhafte Weiterbildung des erfindungsgemäßen Gedankens, insbesondere zur Erzielung eines vorteilhaft scharfen Drucks, beruht auf einer Einbeziehung der Lehre der EP-B-0 133 638. Danach wird auf der Rückseite des Trägers eine Schicht aus einem Wachs oder einem wachsartigen Material gebildet, insbesondere in einer Stärke von nicht mehr als etwa 1 µm und ganz besonders bevorzugt in Form einer molekular ausgebildeten und bis etwa 0,01 µm starken Schicht. Das Beschichtungsmaterial besteht in diesem Fall vorzugsweise aus Paraffin, Silicon, Naturwachsen, insbesondere Carnaubawachs, Bienenwachs, Ozokerit und Paraffinwachs, Synthetikwachsen, insbesondere Säurewachsen, Esterwachsen, teilverseiften Esterwachsen und Polyethylenwachsen, Glykolen bzw. Polyglykol, antistatischen Mitteln und/oder Tensiden. Wird eine derartige rückseitige Beschichtung vorgesehen, dann erfolgt ein ungestörter Wärmeübergang vom Thermodruckkopf auf das Thermotransferband mit der Folge, daß besonders scharfe Drucke erzielt werden.An advantageous development of the idea according to the invention, in particular for Achieving an advantageous sharp pressure is based on the inclusion of the teaching EP-B-0 133 638. Then a layer of a Wax or a wax-like material is formed, especially in a starch of no more than about 1 µm and most preferably in the form of a molecular trained and up to about 0.01 microns thick layer. The coating material in this case preferably consists of paraffin, silicone, natural waxes, in particular carnauba wax, beeswax, ozokerite and paraffin wax, synthetic waxes, especially acid waxes, ester waxes, partially saponified ester waxes and Polyethylene waxes, glycols or polyglycol, antistatic agents and / or Surfactants. If such a rear-side coating is provided, then one takes place undisturbed heat transfer from the thermal print head to the thermal transfer ribbon the consequence that particularly sharp prints are achieved.

Zur Erzielung einer optimalen Druckqualität bei der Anwendung des erfindungsgemäßen Thermotransferbandes in Faxgeräten ist zweckmäßigerweise eine sogenannte Vierschichtstruktur in folgender Reihe und etwa in folgender Schichtstärke auszubilden: Topcoat (Haftschicht) etwa 0,5 bis 0,7 g/m2, wachsgebundene Schicht der Thermotransferfarbe B) etwa 4,0 bis 4,5 g/m2, Trennschicht A) etwa 0,5 bis 1,0 g/m2, Stärke des Trägers (z.B. Polyethylenterephthalat) etwa 4,0 bis 5,0 µm, rückseitige Beschichtung (Antihaftschicht) etwa 0,05 bis 0,1 g/m2. Damit gleichzeitig eine höhere Temperaturlagerbeständigkeit erreicht wird, ist es zweckmäßig, in der Thermotransferfarbe und beim Vierschichtenprodukt im Topcoat ein höherschmelzendes Wachs eines Schmelzpunktes von mindestens 80°C, insbesondere ≥ 85°C, einzuarbeiten.In order to achieve an optimal print quality when using the thermal transfer ribbon according to the invention in fax machines, a so-called four-layer structure is expediently to be formed in the following row and approximately in the following layer thickness: top coat (adhesive layer) approximately 0.5 to 0.7 g / m 2 , wax-bonded layer of thermal transfer ink B. ) about 4.0 to 4.5 g / m 2 , separating layer A) about 0.5 to 1.0 g / m 2 , thickness of the support (e.g. polyethylene terephthalate) about 4.0 to 5.0 μm, back coating ( Non-stick layer) about 0.05 to 0.1 g / m 2 . So that a higher temperature storage stability is achieved at the same time, it is advisable to incorporate a higher melting wax with a melting point of at least 80 ° C, in particular ≥ 85 ° C, in the thermal transfer ink and in the four-layer product in the top coat.

Das oben beschriebene erfindungsgemäße Thermotransferband läßt sich in vielfältiger Weise unter Anwendung üblicher Auftragsverfahren herstellen. Dies kann beispielsweise durch Aufsprühen oder Aufdrucken einer Lösung oder Dispersion, sei es mit Wasser oder einem organischen Lösungsmittel als Dispersions- bzw. Lösungsmittel, durch Auftragen aus der Schmelze, was insbesondere fiir die wachsgebundene Thermotransferfarbe gilt, oder auch durch normales Auftragen mittels einer Rakel in Form einer wäßrigen Suspension mit darin fein verteiltem aufzutragendem Material erfolgen. Im Hinblick auf Umweltschutzgesichtspunkte hat sich folgendes Vorgehen als besonders vorteilhaft erwiesen: Zunächst wird in dünner Schicht eine wäßrige Suspension der Ausgangsmaterialien der Trennschicht auf den Träger aufgetragen, die bei Abdampfen des Wassers die Trennschicht A) entstehen läßt. Nach der Ausbildung der Trennschicht A) schließt sich das Auftragen einer wäßrigen Suspension des Ausgangsmaterials der wachsgebundenen Thermotransferfarbe an, wobei das Wasser in üblicher Weise nach dem Auftrag dieses Materials abgedampft wird. Der gebildete doppelschichtige Belag erfüllt sämtliche Anforderungen, die im Rahmen der gestellten Aufgabe liegen. Die Thermotransferfarbe läßt sich auch in Form einer Schmelze nach üblichen Auftragstechnologien auf die Trennschicht aufbringen, so beispielsweise mit einer Rakel. Die Temperatur der jeweiligen Schmelze sollte dabei in der Regel etwa 100 bis 130°C betragen. Nach dem Auftrag läßt man die aufgetragenen Materialien lediglich abkühlen.The thermal transfer ribbon according to the invention described above can be varied Make way using standard application methods. For example by spraying or printing on a solution or dispersion, either with Water or an organic solvent as a dispersion or solvent, by application from the melt, which is particularly important for the wax-bound thermal transfer ink applies, or by normal application using a doctor blade in the form an aqueous suspension with finely divided material to be applied. In terms of environmental protection, the following procedure has proven to be proved to be particularly advantageous: first, an aqueous one is applied in a thin layer Suspension of the starting materials of the separating layer applied to the carrier, the when the water evaporates, the separating layer A) is formed. After the education separating layer A) is followed by the application of an aqueous suspension of the starting material the wax-bound thermal transfer ink, with the water in is evaporated in the usual way after the application of this material. The educated double layer covering fulfills all requirements within the framework of the Task. The thermal transfer ink can also be in the form of a melt Apply customary application technologies to the interface, for example with a squeegee. The temperature of the respective melt should generally be about 100 to 130 ° C. After the application, the applied materials are left just cool down.

Für die praktische bzw. besonders vorteilhafte Verwirklichung der vorliegenden Erfindung können folgende Rahmenbedingungen bezüglich der Auftragsmengen der einzelnen Schichten bzw. deren Auftragsstärke angegeben werden: Thermotransferfarbschicht B) etwa 1 bis 10 g/m2, vorzugsweise etwa 3 bis 6 g/m2, Trennschicht A) 0,2 bis 5 g/m2, vorzugsweise etwa 0,5 bis 1,5 g/m2, Trägerfilm, insbesondere Polyesterfilm einer Stärke von etwa 2 bis 8 µm, insbesondere einer Stärke von etwa 4 bis 5 µm sowie die angesprochene Rückseitenbeschichtung in einer Auftragsstärke von etwa 0,01 bis 0,2 g/m2, insbesondere von etwa 0,05 bis 0,1 g/m2.For the practical or particularly advantageous implementation of the present invention, the following general conditions can be specified with regard to the application quantities of the individual layers or their application thickness: thermal transfer ink layer B) about 1 to 10 g / m 2 , preferably about 3 to 6 g / m 2 , separating layer A) 0.2 to 5 g / m 2 , preferably about 0.5 to 1.5 g / m 2 , carrier film, in particular polyester film of a thickness of about 2 to 8 microns, in particular a thickness of about 4 to 5 microns, and the addressed back coating in an application thickness of about 0.01 to 0.2 g / m 2 , in particular from about 0.05 to 0.1 g / m 2 .

Die mit der Erfindung verbundenen Vorteile sind insbesondere darin zu sehen, daß vorteilhafte Drucke auch auf nicht gestrichenen und demzufolge rauhen Papieren möglich sind, wobei eine höhere Auflösung erzielt wird, insbesondere bei Einsatz in Faxgeräten. Beim "kalten" und "heißen" Druck stellt sich kein Unterschied bei der Druckqualität ein. Die bessere Temperatur- und Lagerbeständigkeit bei Thermotransferbändern (T ≥ 50°C), ein kleineres Druckgeräusch und eine 100%-ige antistatische Ausrüstung durch Einlagerung von leitfähigem Ruß in die Trennschicht führt ebenfalls zu Vorteilen. Diese Vorteile werden insbesondere dadurch erzielt, indem das wachslösliche Polymer, insbesondere das vorzugsweise eingesetzte Ethylen-Vinylacetat-Copolymerisat, aus der Thermotransferfarbe B) in die Trennschicht A) verlagert und mit Hilfe der Einverleibung von Trennmitteln in die Trennschicht A) eine Druckgeräuschsteuerung erreicht wird.The advantages associated with the invention can be seen in particular in that advantageous prints even on uncoated and therefore rough papers are possible, a higher resolution being achieved, in particular when used in Fax machines. With "cold" and "hot" pressure there is no difference with the Print quality. The better temperature and storage stability with thermal transfer ribbons (T ≥ 50 ° C), a smaller pressure noise and a 100% antistatic Equipment by embedding conductive carbon black in the separation layer also leads to advantages. These advantages are achieved in particular by the wax-soluble polymer, in particular the ethylene-vinyl acetate copolymer which is preferably used, transferred from thermal transfer ink B) to the separation layer A) and with the help of the incorporation of release agents into the separation layer A) Pressure noise control is achieved.

Claims (22)

  1. A thermal transfer ribbon with a conventional carrier including a wax-bonded layer B) of a thermal transfer ink formed on one side of the carrier, the waxes of the wax-bonded layer B) being close cut waxes with closely adjacent melting and solidification points, and including a resin-bonded release layer A) situated between the carrier and the wax-bonded layer, whereby at least the resin-bonded release layer A) includes a wax-soluble polymer and the wax-bonded layer B) of the thermal transfer ink includes 0 to 1.5 % by wt., particularly less than 0.5 % by wt., wax-soluble polymer.
  2. A thermal transfer ribbon as claimed in Claim 1, characterised in that the difference between the melting and solidification point of the close cut waxes is less than 10°C, particularly less than 7°C.
  3. A thermal transfer ribbon as claimed in Claim 1 or 2, characterised in that the melting point of the waxes of the thermal transfer ink is between about 75 and 90°C.
  4. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the release layer A) includes about 10 to 60 % by wt., particularly about 20 to 40 % by wt., wax-soluble polymer.
  5. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the thermal transfer ink of the layer B) has a viscosity of about 50 to 150 mPa·s, particularly about 70 to 120 mPa·s, measured at 100°C with a rotation viscosimeter.
  6. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the waxes of the layer B) are natural waxes in the form of carnauba wax and candalilla wax, chemically modified waxes or hard waxes in the form of modified, microcrystalline wax, ester waxes, paraffin waxes and/or synthetic waxes in the form of Fischer-Tropsch wax or polyethylene wax.
  7. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the wax-soluble polymer is an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, a polyamide, a polyvinyl ether, a polyisobutene and/or an ionomer resin.
  8. A thermal transfer ribbon as claimed in Claim 7, characterised in that, in order to increase the adhesion between the release layer A) and the layer B), the ethylene-vinyl acetate copolymer has a vinyl acetate content of about 16 to 42, particularly about 18 to 40 % by wt.
  9. A thermal transfer ribbon as claimed in Claim 8, characterised in that the melt index MFI (in accordance with DIN 53735) of the ethylene-vinyl acetate copolymer is above about 20 g/10 min., in particular above about 30 g/10 min. (220°C/2.16 kg).
  10. A thermal transfer ribbon as claimed in Claim 6, characterised in that the ethylene-vinyl acetate copolymer has a vinyl acetate content of about 3 to 17, particularly about 6 to 12 % by wt., in order to produce a low adhesion between the release layer A) and the layer B).
  11. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the resin of the release layer A) is a solid resin with a softening range of about 70 to 200°C.
  12. A thermal transfer ribbon as claimed in Claim 11, characterised in that the resin includes an alkide, epoxide, melamine, phenol, urethane and/or polyester resin and/or a polyamide, hydrocarbon resin and/or natural resin.
  13. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the release layer A) has an application thickness of about 0.2 to 5 g/m2, particularly about 1 to 3 g/m2.
  14. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the layer B) of the thermal transfer ink has an application thickness of about 1 to 10 g/m2, particularly about 3 to 6 g/m2.
  15. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the thermal transfer ink includes a colorant, particularly a coloured pigment, in an amount of about 5 to 20 % by wt.
  16. A thermal transfer ribbon as claimed in Claim 15, characterised in that the coloured pigment is carbon black.
  17. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the release layer A) additionally includes conductive carbon black, coloured pigments, dispersion promoters and/or silica.
  18. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the release layer A) includes, in particular, release agents in an amount of about 5 to 20 % by wt.
  19. A thermal transfer ribbon as claimed in Claim 18, characterised in that the release agents are present in the form of non-ionic tensides, emulsifiers and/or polyethylene glycols.
  20. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that the melting point of the wax-bonded thermal transfer ink is between about 60 and 80°C.
  21. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that situated on the layer B) there is an adhesive layer, particularly a paraffin layer with a proportion of finely divided stickiness-inducing hydrocarbon resin, the paraffin having a melting point of, in particular, about 60 to 95°C.
  22. A thermal transfer ribbon as claimed in at least one of the preceding claims, characterised in that situated on the rear surface of the carrier there is a thin layer of a wax or a wax-like material, particularly in a thickness of not more than about 1 µm.
EP99108565A 1998-05-08 1999-05-05 Thermal transfer ribbon Expired - Lifetime EP0955183B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19820769 1998-05-08
DE19820769A DE19820769B4 (en) 1998-05-08 1998-05-08 Thermal transfer ribbon

Publications (3)

Publication Number Publication Date
EP0955183A2 EP0955183A2 (en) 1999-11-10
EP0955183A3 EP0955183A3 (en) 2000-09-06
EP0955183B1 true EP0955183B1 (en) 2003-11-12

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP99108565A Expired - Lifetime EP0955183B1 (en) 1998-05-08 1999-05-05 Thermal transfer ribbon

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Country Link
EP (1) EP0955183B1 (en)
CA (1) CA2271430A1 (en)
DE (2) DE19820769B4 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6926790B2 (en) 2000-05-17 2005-08-09 E. I. Du Pont De Nemours And Company Overcoated donor elements and their process of use
DE10143188A1 (en) * 2001-09-04 2003-04-03 Thuringia Netzsch Maschinen Un Machine system for transfer of colour images onto a printing plate
DE10237047A1 (en) * 2002-08-09 2004-02-26 Emtec Magnetics Gmbh Thermal transfer product, used in printing, especially with flat head or near edge printer, e.g. on paper and film, has ink-release layer containing binder in addition to wax and pigment or separate ink and release layers
CN114148109B (en) * 2021-11-09 2023-05-02 焦作卓立膜材料股份有限公司 Degradable carbon ribbon and preparation method thereof

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3328990C2 (en) * 1983-08-11 1985-12-12 Pelikan Ag, 3000 Hannover Thermal ribbon and process for its production
DE3808462C2 (en) * 1987-03-17 1996-04-25 Toyo Ink Mfg Co Heat-sensitive transfer material
DE3825437C1 (en) * 1988-07-27 1989-11-16 Pelikan Ag, 3000 Hannover, De
US5292572A (en) * 1989-07-26 1994-03-08 Konica Corporation Heat-transfer image recording medium
US5273808A (en) * 1989-09-29 1993-12-28 Konica Corporation Thermal transfer recording medium
DE19548033A1 (en) * 1995-12-21 1997-07-03 Pelikan Produktions Ag Thermal transfer ribbon
DE19612393A1 (en) * 1996-03-28 1997-10-02 Pelikan Produktions Ag Thermal transfer ribbon

Also Published As

Publication number Publication date
DE19820769B4 (en) 2004-02-05
DE59907677D1 (en) 2003-12-18
CA2271430A1 (en) 1999-11-08
EP0955183A3 (en) 2000-09-06
EP0955183A2 (en) 1999-11-10
DE19820769A1 (en) 1999-11-11

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