EP1075963B1 - Thermal transfer sheet for laser-induced marking of a lithographic printing cylinder - Google Patents

Thermal transfer sheet for laser-induced marking of a lithographic printing cylinder Download PDF

Info

Publication number
EP1075963B1
EP1075963B1 EP00116753A EP00116753A EP1075963B1 EP 1075963 B1 EP1075963 B1 EP 1075963B1 EP 00116753 A EP00116753 A EP 00116753A EP 00116753 A EP00116753 A EP 00116753A EP 1075963 B1 EP1075963 B1 EP 1075963B1
Authority
EP
European Patent Office
Prior art keywords
thermal
transfer film
film according
polymer
pigments
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP00116753A
Other languages
German (de)
French (fr)
Other versions
EP1075963A2 (en
EP1075963A3 (en
Inventor
Josef Dr. Schneider
Thomas Dr. Hartmann
Andrea Dr. Fuchs
Hans-Christoph Beltle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Manroland AG
Original Assignee
MAN Roland Druckmaschinen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MAN Roland Druckmaschinen AG filed Critical MAN Roland Druckmaschinen AG
Publication of EP1075963A2 publication Critical patent/EP1075963A2/en
Publication of EP1075963A3 publication Critical patent/EP1075963A3/en
Application granted granted Critical
Publication of EP1075963B1 publication Critical patent/EP1075963B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/1091—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by physical transfer from a donor sheet having an uniform coating of lithographic material using thermal means as provided by a thermal head or a laser; by mechanical pressure, e.g. from a typewriter by electrical recording ribbon therefor

Definitions

  • the invention relates to a generic thermal transfer film, the as a donor element for imaging a lithographic printing form cylinder, is particularly suitable for offset printing, by laser-induced transmission.
  • the invention also relates to a method for producing the film and Intermediates for it.
  • a printing method is known in which a printing form cylinder is punctiform and figuratively provided with plastic. This printing form cylinder is then coated with printing inks for an offset process and the Printing ink of the ink-guiding areas is picked up by a rubber roller and transferred to the substrate to be printed. For a quick one Changing the print motifs, especially for short runs, it is desirable the process within a device is computer-controlled if possible and on the other hand to perform without changing moving parts. The one in EP-B-0 698 488 presented printing device meets this need.
  • the printing form cylinder used in the above device is made with a polymer made by a thermal transfer ribbon comes, punctiform and pictorial.
  • suitable lithographic printing form that means on the printing form cylinder clear separation of the hydrophilic areas (those not with polymer occupied parts on the printing form cylinder) and hydrophobic areas (the polymer-coated parts on the printing form cylinder, which are used later in the printing process represent the color-carrying areas) - certain physical and chemical parameters of the thermal transfer film, in particular for a Thermal transfer ribbon, set and optimized. It has been shown that usual thermal transfer foils and tapes do not meet the requirements or only partly do justice.
  • EP-A1-0 727 321 relates to an image-forming material a support and an imaging layer thereon, the one Contains colorant, the imaging layer being hardened was used to determine the adhesive force between the imaging layer and diminish the support, thereby causing an image to pass through imagewise exposing the imaging layer with a Light of high energy density is formed.
  • the thermal transfer film according to the invention consists of a substrate layer 1, e.g. a carrier film or a carrier tape, from one if possible heat-resistant plastic and a donor layer 2, i.e. the heat-sensitive transferable layer as defined in the main claim.
  • a substrate layer e.g. a carrier film or a carrier tape
  • a donor layer i.e. the heat-sensitive transferable layer as defined in the main claim.
  • the transfer process is irreversible and directed Plastic cools due to the high heat capacity of e.g. made of metal Cylinder immediately and adheres to the printing form cylinder.
  • the transferred layer is essentially in two steps aftertreated, namely in a first step a fixing step is carried out, where, due to the effects of heat, the plastic layer better adheres to the material of the printing form and in a second step in which hydrophilizes will, i.e.
  • hydrophilicity means water friendliness as a measure for wetting with water under dynamic conditions.
  • the substrate layer must withstand mechanical stresses during the course of the transport device, e.g. the band station and under local Be resistant to heat.
  • the substrate layer must also be related on the chemicals used in the manufacture of the thermal transfer ribbon be chemically inert.
  • the substrate is preferably used for imaging used wavelength optically transparent.
  • the substrate should also be against electrostatic charge be neutral, but be an electrical insulator.
  • the thickness of the substrate layer is 50 ⁇ m to 4 ⁇ m or up to 5 ⁇ m, especially 12 to 6 ⁇ m. An optimum is 7.5 ⁇ m.
  • the parameters are essentially the optical transmission (permeability), the mechanical strength even at higher temperatures, the thermal conductivity and the thermal stability and dimensional stability at higher temperatures, a compromise must be sought between these parameters.
  • the optical transmission increases with decreasing thickness of the substrate layer.
  • the mechanical strength in turn improves with increasing thickness of the Substrate layer.
  • the passage of heat increases on the one hand with decreasing thickness to.
  • the mechanical stability increases with increasing thickness the substrate layer.
  • the thickness of the substrate layer should be sufficient that with the action of a laser with a power of 300 mJ for transmission necessary material is generated by material of the donor layer and thus a effective transfer of material of the donor layer takes place.
  • the tensile strength at break also plays a role.
  • the tensile strength at break in the machine direction should be greater than 200 N / mm 2 , preferably greater than 250 N / mm 2 , particularly preferably greater than 270 N / mm 2 .
  • the transverse direction is greater than 180 N / mm 2 , preferably greater than 220 N / mm 2 , in particular greater than 270 N / mm 2 .
  • the tensile strength is essentially determined by the mechanical stresses caused by the belt station and - depending on the width of the belt - by the local heat.
  • the shrinkage should be less than 8%, in particular less than 6.5%, particularly preferred less than 5%.
  • the substrate is made of a plastic that the mechanical properties mentioned above also at a temperature of 150 ° C or greater. Therefore come in particular optically clear, heat-resistant and high-strength plastics.
  • polypropylene and PVCP can be used.
  • the ones that can be used Plastics but polyester, polyaryl ether ether ketone (PEEK), polyphenylene ether (PPE) and / or polycarbonates.
  • Polyesters are preferred, among them polyesters are preferred, those of dicarboxylic acids and diols and / or of hydroxycarboxylic acids or the corresponding lactones are derived, such as Polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates and block copolyether esters, derived from polyethers with hydroxyl end groups and also polyester, modified with polycarbonates. Polyethylene naphthalenedicarboxylates are also suitable. Commercial PET products are e.g. Hostaphan® and Mylar®.
  • the plastic for the substrate layer should have little preferably contain no plasticizer.
  • Plasticizers are essentially of low molecular nature and can therefore be used in the conversion of the Vaporize the energy of the laser light in heat and lead to a plasma effect. Occurring plasma reflects the penetrating laser beam, so that in the donor layer is used to soften and eject the one to be transferred Material heat required is no longer achieved. Plasticizers that are used Exposure to a laser with a power of 300 mJ with the above Films or tapes that do not produce a plasma effect can be tolerated become. The same applies to concentrations of common plasticizers.
  • the optical transmission is usually determined by the thickness of the tape and the choice of material certainly.
  • the optical transmission depends on the wavelength.
  • the wavelength range for IR semiconductor lasers is between 700 and 1600 nm.
  • the ranges are preferably 800 to 900 nm, in particular 850 to 820 nm on the one hand and 1000 to 1200 nm or 1070 to 1030 nm on the other hand.
  • the wavelength is approximately 1064 nm.
  • the transmission for the substrate layer of> 70% IR light is in the wavelength range from 700 to 1600 nm, more preferably> 85%. Transmission of IR light in the wavelength range is particularly preferred from 800 to 1100 nm from> 85%.
  • a point laser can be used as the laser be used. However, IR semiconductor laser diode arrays are preferred.
  • the substrate must be chemically inert, i.e. the chemicals used in the manufacturing process of the thermal transfer ribbon are used, must not adversely affect the substrate.
  • these are organic solvents, preferably ketones, aliphatic and cycloaliphatic hydrocarbons as well as acids and bases.
  • the width of the Tape on 3 mm to 50 mm, preferably 8 mm to 30 mm, preferably 10 mm up to 15 mm.
  • the polymer to be transferred contains an auxiliary, who supports this process.
  • These substances can organic dyes or organic coloring agents, provided that that they do not decompose when light energy is converted into heat energy.
  • organic dyes or pigments examples include Benzothiazoles, quinolines, cyanine dyes or pigments, perylene dyes or pigments, polymethine dyes and pigments, such as oxonol dyes and - pigments and merocyanine dyes and pigments.
  • KF 805 PINA from Riedl de Haen a benzothiazole compound
  • KF 810 PINA from Riedl de Haen a quinoline compound
  • ADS840MI, ADS840MT, ADS840AT, ADS890MC, ADS956BI, ADS800WS, ADS96HO from American Dye Source Inc. 3,3'-diethylthiatricarbocyanine p-toluenesulfonate (Cyanine dye compounds), perylene-3,4,8,10-tetracarboxylic anhydride (a perylene compound) as well as Epolite V-63 and Epolite III-178 from Epolin Inc., Newmark.
  • the organic dyes or pigments are in an amount of 5 to 40 wt .-%, preferably 10 to 30 wt .-%, the dry mass of the donor layer used. These dyes can be used individually or applied in a mixture to the absorption maximum in to shift the wavelength range of the laser used.
  • inorganic substances are of interest, in particular those which do not decompose when light energy is converted into heat energy.
  • Such substances are, for example, titanium dioxide, aluminum oxide and other metal oxides and inorganic color pigments.
  • Magnetite can be mentioned here: Fe 3 O 4 ; Spinel black: Cu (Cr, Fe) 2 O 4 , Co (Cr, Fe) 2 O 4 ; Manganese ferrite: MnFe 2 O 4 . These substances are used in an amount of up to 20% by weight.
  • the aforementioned substances, namely organic dyes or Colorant, inorganic substance involved in the conversion of light energy not decomposed in thermal energy, and soot can be used individually or in a mixture become.
  • the amount of heat sensitive and / or laser sensitive Substance depends on the ability to convert light energy into sufficient thermal energy to transfer that located on the substrate layer to be transferred.
  • the polymer of the donor layer performs the following functions in particular out. Firstly, it will soften quickly under the influence of the laser beam, develop the required pressure at the interface of the substrate layer and transferred to the printing form cylinder as a semi-solid graft. Is liable there the plastic thus transferred due to hydrophilic groups on the hydrophilic Surface of the printing form cylinder. Finally, the polymer should be first a fixing step by heating and then a hydrophilization step of the survive the finished printing form cylinder. In this step, the free ones Metal surfaces of the printing form cylinder hydrophilized and the plastic areas profiled on the printing form cylinder. In addition, it should now be on the printing form cylinder plastic, printing ink and a have the longest possible service life.
  • the polymer is aqueous at a pH greater than 10 Solution soluble but insoluble in the fountain solution that is normally used in Offset paper printing is used. This is achieved in that the polymer is water-soluble for a pH greater than 10 deviating from the fountain solution designed.
  • An alkaline range with a pH is preferred greater than 10.5, in particular greater than 11.
  • its number average molecular weight should preferably not be 20,000 exceed.
  • its number average molecular weight should be preferred Do not fall below 1000, otherwise there is insufficient water resistance is achieved.
  • the range is preferably between 1000 and 15,000, especially between 1,000 and 10,000.
  • the polymers have to accept printing ink.
  • a surface tension preferably between 50 and 10 mN / m, in particular between 40 and 23 mN / m, particularly preferably in the range of 28 and 32 mN / m, significant.
  • the surface tension is measured via contact angle measurement with 3 + n test liquids and is according to Wendt, Own and Rabel evaluated.
  • the transferred polymer In order for the transferred polymer to adhere sufficiently to the hydrophilic printing form cylinder, it has acidic groups. These groups can be selected from the groups -COOH, -SO 3 H, -OSO 3 H and -OPO 3 H 2 as well as the optionally alkyl- or aryl-substituted amides thereof.
  • the alkyl group can have 1 to 6, preferably 1 to 4, carbon atoms, the aryl group can have 6 to 10, preferably 6, carbon atoms.
  • the polymer also contains an aromatic group. Phenyl groups are preferred.
  • the polymer preferably originates from the polymerization of ⁇ , ⁇ -unsaturated carboxylic, sulfonic, sulfuric and phosphoric acids or esters or their amides and styrene as defined above, and also their derivatives and optionally ⁇ , ⁇ -unsaturated carboxylic esters.
  • the acidic monomers and the aromatic vinyl monomers should be selected such that the polymer has a glass transition temperature T g between 30 and 100 ° C., in particular 30 and 90 ° C., preferably between 55 and 65 ° C.
  • the polymer preferably has a ceiling temperature in the range of the melting point, the melting range being between 80 and 150, in particular 90 and 140, preferably 105 to 115 ° C., particularly preferably around 110 ° C. Copolymers which contained substantial amounts of ⁇ -methylstyrene proved to be less advantageous.
  • Suitable polymers can be found in US-A-4 013 607, US-A-4 414 370 and in U.S.-A-4,529,787. Resins disclosed therein can e.g. essentially be completely solved if a sufficient part, for example 80-90 % of these groups with an aqueous solution of basic substances such as borax, Amines, ammonium hydroxide, NaOH and / or KOH is neutralized.
  • basic substances such as borax, Amines, ammonium hydroxide, NaOH and / or KOH is neutralized.
  • styrene-acrylic acid resin with an acid number of about 190 not less than contain about 0.0034 equivalents of -COOH groups per gram of resin and would essentially be solved completely if a minimum of about 80-90% of the -COOH groups neutralized by an aqueous alkaline solution become.
  • the acid number can range between 120 and 550, 150 and 300, e.g. 150 to 250 lie.
  • the combinations of Monomers are preferably styrene-acrylic acid, styrene-maleic anhydride, Methyl methacrylate-butyl acrylate-methacrylic acid, ⁇ -methylstyrene / styrene-ethyl acrylate-acrylic acid, Styrene-butyl acrylate-acrylic acid, styrene-methyl acrylate-butyl acrylate-methyl acrylic acid.
  • An alkali-soluble resin with 68% styrene / 32% acrylic acid with a molecular weight of 500-10000 can be mentioned.
  • Other Resins have an acid number of about 200 and a molecular weight of about 1400.
  • styrene ( ⁇ -methylstyrene) acrylic acid (acrylic acid ester) resins a number average molecular weight of 2500-4500 and a weight average molecular weight of 6500-9500. The acid number is included 170-200.
  • Exemplary polymers have 60-80% by weight of aromatic monoalkenyl monomers and 40-20% by weight of (meth) acrylic acid monomers and optionally 0-20% by weight of acrylic monomer containing no carboxyl groups. Mixtures from 10: 1 to 1: 2 or 1: 1, preferably 8: 1 to 1: 2, for example 2: 1 up to 1: 2 styrene / ⁇ -methylstyrene can be used. Not very advantageous However, copolymers have been found to contain substantial amounts of ⁇ -methylstyrene contained.
  • the thermal transfer ribbon used for the method has a coating weight in the range from 0.8 to 5 g / m 2 +/- 0.2 and is preferably in the range from 1.6 to 2.0 g / m 2 .
  • the wetting aid has various functions.
  • the wetting aid lies after the transfer also at the border area between the metal surface and transferred polymer, so that there increases the adhesion becomes. Finally, it smoothes when fixing, i.e. with a subsequent heating of the transferred polymer, the surface of the transferred polymer, so that the structure of the pixel is improved.
  • the wetting aid will selected from solvents such as alcohols, ketones, esters of phosphoric acid, Glycol ethers and anionic surfactants, especially alcohols and ketones, are preferred Ketones, particularly preferably methyl ethyl ketone.
  • solvents used as a wetting aid originate from the manufacturing step of the thermal transfer ribbon.
  • wetting aids can be used in small amounts (e.g. 0.05-8% by weight, preferably 0.5-5% by weight of the dry mass of the donor layer) by the Manufacturing process are introduced. Another advantage of being present A wetting aid is an intrinsic temperature control during the transfer process and thermal post-treatment. About the properties Boiling point, range, enthalpy of vaporization and heat capacity are at a maximum upper limit temperature for both processes for the necessary time window Are defined. For example, microscopic desorption processes in the In the case of a formulation based on carbon black, an upper limit temperature pretend. Overheating of the transferred mass can be caused by both external control of the heat sources as well as by the composition of the Mass itself can be influenced and thus creates a high level of security in the Process management.
  • the thermal transfer ribbon is produced in the usual way.
  • the Mass is then applied with a Meyer bar or by the engraving process.
  • the thickness of the transfer layer is 0.5 to 5 ⁇ m, preferably 0.8 to 4 ⁇ m, in particular 1 to 3 ⁇ m, preferably 1.5 to 2.5 ⁇ m, dry layer thickness.
  • the tape is on a Coil wound and inserted in a tape station.
  • the pixel transmission unit receives data for the from a data memory Illustration of the printing form cylinder.
  • the thermal transfer ribbon moves with it Help a tape station relative to yourself during the transition process itself but independently moving pressure cylinder. This relative speed and the chronological sequence of the data controls the mapping on the printing cylinder.
  • the radiated light energy is converted into thermal energy, which at the interface between the substrate layer and the donor layer of the Thermal transfer ribbon causes a particularly sharp rise in temperature. This increase in temperature causes the above-mentioned boundary layer Generates gases that counter the now softened material of the donor layer spin the metal of the printing form cylinder.
  • the substance parts of the transferred Mark material on the surface of the printing form cylinder due to the oleophilic property of the ink-guiding areas during later printing.
  • a polyethylene terephthalate film (PET) Hostaphan® from Hoechst with a thickness of 7.5 ⁇ m is coated with a Meyer bar with a mass of the following composition to a dry layer weight of 1.8 g / m 2 .

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
  • Laminated Bodies (AREA)

Description

Die Erfindung betrifft eine gattungsgemäße Thermotransferfolie, die als Donorelement zur Bebilderung eines lithographischen Druckformzylinders, insbesondere zum Offsetdruck, durch laserinduzierte Übertragung geeignet ist. Die Erfindung betrifft außerdem ein Verfahren zur Herstellung der Folie sowie Zwischenprodukte dafür.The invention relates to a generic thermal transfer film, the as a donor element for imaging a lithographic printing form cylinder, is particularly suitable for offset printing, by laser-induced transmission. The invention also relates to a method for producing the film and Intermediates for it.

Bekannt ist ein Druckverfahren, bei dem ein Druckformzylinder punktförmig und bildmäßig mit Kunststoff versehen wird. Dieser Druckformzylinder wird dann für ein Offset-Verfahren mit Druckfarben beschichtet und die Druckfarbe der farbführenden Bereiche wird von einer Gummiwalze aufgenommen und auf das zu bedruckende Substrat übertragen. Für einen raschen Wechsel der Druckmotive, insbesondere für Kleinauflagen, ist es erwünscht, den Vorgang innerhalb einer Vorrichtung zum einen möglichst rechnergesteuert und zum anderen ohne Wechsel beweglicher Teile aufzuführen. Die in EP-B-0 698 488 vorgestellte Druckvorrichtung erfüllt diesen Bedarf.A printing method is known in which a printing form cylinder is punctiform and figuratively provided with plastic. This printing form cylinder is then coated with printing inks for an offset process and the Printing ink of the ink-guiding areas is picked up by a rubber roller and transferred to the substrate to be printed. For a quick one Changing the print motifs, especially for short runs, it is desirable the process within a device is computer-controlled if possible and on the other hand to perform without changing moving parts. The one in EP-B-0 698 488 presented printing device meets this need.

Der in der vorstehend genannten Vorrichtung verwendete Druckformzylinder wird mit einem Polymer, das von einem Thermotransferband stammt, punktförmig und bildmäßig belegt. Zur Gewinnung einer für den Offsetdruck geeigneten lithographischen Druckform ― das bedeutet auf dem Druckformzylinder deutliche Trennung der hydrophilen Bereiche (die nicht mit Polymer belegten Teile auf dem Druckformzylinder) und hydrophoben Bereiche (die mit Polymer belegten Teile auf dem Druckformzylinder, die später beim Druckvorgang die farbführenden Bereiche darstellen) - müssen bestimmte physikalische und chemische Parameter der Thermotransferfolie, insbesondere für ein Thermotransferband, eingestellt und optimiert werden. Es hat sich gezeigt, daß übliche Thermotransferfolien und -bänder den Erfordernissen nicht oder nur zum Teil gerecht werden.The printing form cylinder used in the above device is made with a polymer made by a thermal transfer ribbon comes, punctiform and pictorial. To obtain one for offset printing suitable lithographic printing form - that means on the printing form cylinder clear separation of the hydrophilic areas (those not with polymer occupied parts on the printing form cylinder) and hydrophobic areas (the polymer-coated parts on the printing form cylinder, which are used later in the printing process represent the color-carrying areas) - certain physical and chemical parameters of the thermal transfer film, in particular for a Thermal transfer ribbon, set and optimized. It has been shown that usual thermal transfer foils and tapes do not meet the requirements or only partly do justice.

EP-A1-0 727 321 betrifft ein bilderzeugendes Material mit einem Träger und darauf einer bilderzeugenden Schicht, die ein Färbemittel enthält, wobei die bilderzeugende Schicht gehärtet wurde, um die Haftkraft zwischen der bilderzeugenden Schicht und dem Träger zu vermindern, wodurch ein Bild durch bildmäßiges Belichten der bilderzeugenden Schicht mit einem Licht hoher Energiedichte gebildet wird. EP-A1-0 727 321 relates to an image-forming material a support and an imaging layer thereon, the one Contains colorant, the imaging layer being hardened was used to determine the adhesive force between the imaging layer and diminish the support, thereby causing an image to pass through imagewise exposing the imaging layer with a Light of high energy density is formed.

Aufgabe der vorliegenden Erfindung ist es, eine verbesserte Thermotransferfolie zur Bebilderung eines Druckformzylinders durch eine laserinduzierte Übertragung eines Polymers aus einer Donorschicht der Thermotransferfolie bereitzustellen, wobei die nachstehenden Erfordernisse zu beachten sind:

  • 1. der Träger muß den mechanischen Anforderungen des Transports, den optischen Anforderungen des Durchtritts eines Laserstrahls und den thermischen Anforderungen bei der Erwärmung der aufgetragenen Beschichtung genügen;
  • 2. die auf der Folie befindliche, punktweise und bildmäßig zu übertragende Beschichtung soll fest an der Metalltrommel haften und eine für eine möglichst hohe Auflage ausreichende Standzeit bei gleichbleibender Druckqualität bieten; und
  • 3. die aufgetragene Polymerschicht auf dem Druckformzylinder sollte nach dem Druckvorgang in einfacher Weise umweltschonend und schnell entfernt werden können, damit alsbald ein neuer Druckvorgang beginnen kann.
    • The object of the present invention is to provide an improved thermal transfer film for imaging a printing form cylinder by laser-induced transfer of a polymer from a donor layer of the thermal transfer film, the following requirements being observed:
  • 1. the carrier must meet the mechanical requirements of transportation, the optical requirements for the passage of a laser beam and the thermal requirements for heating the applied coating;
  • 2. The coating on the film, which is to be transferred point by point and image-wise, should adhere firmly to the metal drum and offer a service life which is sufficient for the longest possible print run with the same print quality; and
  • 3. The applied polymer layer on the printing form cylinder should be able to be removed quickly and in an environmentally friendly manner after the printing process, so that a new printing process can begin immediately.

    • Die vorstehende Aufgabe und weitere der nachstehenden Beschreibung zu entnehmende Aufgaben wurden durch den Gegenstand des Hauptanspruchs gelöst. Weitere besondere Ausführungsformen werden in den Unteransprüchen definiert.The above task and others of the description below Tasks to be extracted were the subject of the main claim solved. Further special embodiments are set out in the subclaims Are defined.

    Die erfindungsgemäße Thermotransferfolie besteht aus einer Substratschicht 1, z.B. eine Trägerfolie oder ein Trägerband, aus einem möglichst wärmebeständigen Kunststoff und darauf aufgetragen eine Donorschicht 2, d.h. die wärmeempfindliche übertragbare Schicht, wie im Hauptanspruch definiert. Durch Einwirkung des Laserstrahls 3 von der Rückseite des Thermotransferbands, d.h. von der im Sinne einer Donorschicht unbeschichteten Seite der Substratschicht 1 wird in der Donorschicht Wärme induziert, die zum Erweichen und schließlich zum Ablösen von Kunststoffteilchen führt. Aufgrund von gasförmigen Stoffen, die insbesondere an der Grenzschicht 5 zwischen der Substratschicht 1 und der darauf aufgetragenen Donorschicht 2 entstehen, wird die wärmeempfindliche Donorschicht im weichen bis halbfesten Zustand bildmäßig aus dem Verbund der Substrat/Donorschicht herausgelöst und auf den Formzylinder übertragen. Die dabei entstehenden Gase verstärken die Vorzugsrichtung hin zum Formzylinder. Zusätzlich wird durch die Art der Antragung des Bandes (siehe EP-B-0 698 488) der Transfervorgang unumkehrbar und gerichtet Der Kunststoff kühlt aufgrund der hohen Wärmekapazität des z.B. aus Metall bestehenden Zylinders sofort ab und haftet am Druckformzylinder. Nachdem der gesamte Druckformzylinder durch einen spiralförmigen Auftragungsvorgang in hoher Geschwindigkeit punktförmig und bildmäßig mit einer Kunststoffschicht versehen wurde, wird die übertragene Schicht im wesentlichen in zwei Schritten nachbehandelt, nämlich in einem ersten Schritt wird ein Fixierschritt vorgenommen, bei dem durch die Wärmeeinwirkung u.a. die Kunststoffschicht besser an dem Material der Druckform haftet und in einem zweiten Schritt, in dem hydrophiliert wird, d.h. es werden die auf dem Druckformzylinder freiliegenden Bereiche durchgehend hydrophiler gestaltet (hydrophiliert) und gleichzeitig wird das Profil, d.h. die Randschärfe, des übertragenen Polymers schärfer gestaltet. Hydrophilie bedeutet in dieser Anmeldung die Wasserfreundlichkeit als ein Maß für die Benetzung mit Wasser unter dynamischen Bedingungen.The thermal transfer film according to the invention consists of a substrate layer 1, e.g. a carrier film or a carrier tape, from one if possible heat-resistant plastic and a donor layer 2, i.e. the heat-sensitive transferable layer as defined in the main claim. By the action of the laser beam 3 from the back of the thermal transfer ribbon, i.e. from the uncoated side of the donor layer Substrate layer 1 is induced in the donor layer to heat it and eventually leads to the detachment of plastic particles. Due to gaseous Substances in particular at the boundary layer 5 between the substrate layer 1 and the donor layer 2 applied thereon, the heat-sensitive donor layer in the soft to semi-solid state imagewise detached from the composite of the substrate / donor layer and onto the forme cylinder transfer. The resulting gases reinforce the preferred direction towards the forme cylinder. In addition, the type of application of the volume (see EP-B-0 698 488) the transfer process is irreversible and directed Plastic cools due to the high heat capacity of e.g. made of metal Cylinder immediately and adheres to the printing form cylinder. After the whole Printing forme cylinder by a spiral application process high speed punctiform and pictorial with a plastic layer has been provided, the transferred layer is essentially in two steps aftertreated, namely in a first step a fixing step is carried out, where, due to the effects of heat, the plastic layer better adheres to the material of the printing form and in a second step in which hydrophilizes will, i.e. there will be those exposed on the printing form cylinder Areas made more hydrophilic throughout (hydrophilized) and at the same time the profile, i.e. the edge sharpness of the transferred polymer is sharper. In this application, hydrophilicity means water friendliness as a measure for wetting with water under dynamic conditions.

    Der Druckformzylinder weist in unbebildertem Zustand eine Oberfläche mit durchgehend hydrophilen Eigenschaften auf. Hierfür eignen sich beispielsweise plasma- oder flammgespritzte Keramiken bzw. Metalloberflächen, wie Chrom, Messing (Cu52-65% Zn48-35%, z.B. Boltomet L® Cu63Zn37) und Edelstähle im Sinne von hochlegierten Stählen (nach DIN17440: 1.43xx (xx=01, 10, ...), 1.4568, 1.44xx (xx=04, 35, 01 ...)) etc.

  • Figur 1 erläutert den Druckvorgang. Ein Laserstrahl 3 trifft auf die Rückseite 1 eines Thermotransferbandes oder einer Thermotransferfolie 1,2. Der Druckformzylinder dreht sich in der angegebenen Richtung. Der Druckformzylinder 4 wird spiralförmig mit Material der Donorschicht 2 bebildert.
  • Figur 2 erläutert den Übertragungsvorgang genauer. Aus dem Verbund der Donorschicht 2 werden nach Auftreffen des Laserstrahls 3 auf die Rückseite 1 des Thermotransferbandes (oder der Thermotransferfolie) Polymerteilchen 7 herausgelöst und haften auf dem Druckformzylinder 4. Die Vorgänge an der Grenzschicht 5 bzw. 6 werden in der Beschreibung genauer erläutert.
    • In the unimaged state, the printing form cylinder has a surface with consistently hydrophilic properties. For this purpose, plasma or flame sprayed ceramics or metal surfaces such as chrome, brass (Cu52-65% Zn48-35%, e.g. Boltomet L® Cu63Zn37) and stainless steels in the sense of high-alloy steels (according to DIN17440: 1.43xx (xx = 01 , 10, ...), 1.4568, 1.44xx (xx = 04, 35, 01 ...)) etc.
  • Figure 1 explains the printing process. A laser beam 3 strikes the back 1 of a thermal transfer ribbon or a thermal transfer film 1, 2. The printing form cylinder rotates in the specified direction. The printing form cylinder 4 is spirally imaged with material of the donor layer 2.
  • Figure 2 explains the transfer process in more detail. After the laser beam 3 strikes the back 1 of the thermal transfer ribbon (or the thermal transfer film), polymer particles 7 are detached from the composite of the donor layer 2 and adhere to the printing form cylinder 4. The processes at the boundary layer 5 and 6 are explained in more detail in the description.

    • Die SubstratschichtThe substrate layer

    Die Substratschicht muß gegen mechanische Spannungen während des Laufes der Transportvorrichtung, z.B. der Bandstation und unter örtlichem Wärmeeinfluß beständig sein. Die Substratschicht muß darüber hinaus in bezug auf die bei der Herstellung des Thermotransferbands verwendeten Chemikalien chemisch inert sein. Vorzugsweise ist das Substrat für die zur Bilderzeugung verwendete Wellenlänge optisch durchlässig. Das Substrat sollte auch gegen elektrostatische Aufladung neutral sein, aber ein elektrischer Isolator sein.The substrate layer must withstand mechanical stresses during the course of the transport device, e.g. the band station and under local Be resistant to heat. The substrate layer must also be related on the chemicals used in the manufacture of the thermal transfer ribbon be chemically inert. The substrate is preferably used for imaging used wavelength optically transparent. The substrate should also be against electrostatic charge be neutral, but be an electrical insulator.

    Die Dicke der Substratschicht beträgt 50 µm bis 4µm oder bis 5 µm, insbesondere 12 bis 6 µm. Ein Optimum liegt bei 7,5 µm. Die die Dicke bestimmenden Parameter sind im wesentlichen die optische Transmission (Durchlässigkeit), die mechanische Festigkeit auch bei höherer Temperatur, die Wärmeleitfähigkeit und die thermische Stabilität und Maßhaltigkeit bei höherer Temperatur, wobei zwischen diesen Parametern ein Kompromiß zu suchen ist. Die optische Transmission steigt mit abnehmender Dicke der Substratschicht. Die mechanische Festigkeit wiederum verbessert sich mit steigender Dicke der Substratschicht. Der Wärmedurchtritt nimmt einerseits mit abnehmender Dicke zu. Andererseits erhöht sich die mechanische Stabilität mit zunehmender Dicke der Substratschicht.The thickness of the substrate layer is 50 µm to 4 µm or up to 5 µm, especially 12 to 6 µm. An optimum is 7.5 µm. The ones that determine the thickness The parameters are essentially the optical transmission (permeability), the mechanical strength even at higher temperatures, the thermal conductivity and the thermal stability and dimensional stability at higher temperatures, a compromise must be sought between these parameters. The optical transmission increases with decreasing thickness of the substrate layer. The mechanical strength in turn improves with increasing thickness of the Substrate layer. The passage of heat increases on the one hand with decreasing thickness to. On the other hand, the mechanical stability increases with increasing thickness the substrate layer.

    Zum anderen sollte die Dicke der Substratschicht ausreichen, damit die bei Einwirkung eines Lasers mit einer Leistung von 300 mJ zur Übertragung von Material der Donorschicht notwendige Wärme erzeugt wird und somit eine wirksame Übertragung von Material der Donorschicht stattfindet.On the other hand, the thickness of the substrate layer should be sufficient that with the action of a laser with a power of 300 mJ for transmission necessary material is generated by material of the donor layer and thus a effective transfer of material of the donor layer takes place.

    Neben der Dicke spielt die Zugfestigkeit beim Bruch ebenfalls eine Rolle. Insbesondere sollte die Zugfestigkeit beim Bruch in Maschinenrichtung größer 200 N/mm2, vorzugsweise größer 250 N/mm2, besonders bevorzugt größer 270 N/mm2, sein. Für die Querrichtung gilt größer 180 N/mm2, bevorzugt größer 220 N/mm2, insbesondere größer 270 N/mm2. Die Zugfestigkeit wird im wesentlichen durch die mechanischen Beanspruchungen durch die Bandstation und - in Abhängigkeit von der Breite des Bandes - durch die örtliche Wärmeeinwirkung bestimmt.In addition to the thickness, the tensile strength at break also plays a role. In particular, the tensile strength at break in the machine direction should be greater than 200 N / mm 2 , preferably greater than 250 N / mm 2 , particularly preferably greater than 270 N / mm 2 . The transverse direction is greater than 180 N / mm 2 , preferably greater than 220 N / mm 2 , in particular greater than 270 N / mm 2 . The tensile strength is essentially determined by the mechanical stresses caused by the belt station and - depending on the width of the belt - by the local heat.

    Für die Genauigkeit der Erzeugung des Bildes auf dem Druckformzylinder ist unter anderem auch die Formstabilität der Substratschicht unter thermischer Belastung von Bedeutung. Bei einer thermischen Belastung von 150°C sollte die Schrumpfung kleiner 8 %, insbesondere kleiner 6,5 %, besonders bevorzugt kleiner 5 %, sein. For the accuracy of the creation of the image on the printing form cylinder is among other things the dimensional stability of the substrate layer under thermal Load of importance. With a thermal load of 150 ° C the shrinkage should be less than 8%, in particular less than 6.5%, particularly preferred less than 5%.

    Thermische Formstabilität der Substratschicht wird vor allem bei den nachstehenden Vorgängen gefordert:

  • a) bei der Herstellung, Lagerung und beim Transport,
  • b) bei der Haftung der Donorschicht auf der Substratschicht im Falle unterschiedlicher Ausdehnungskoeffizienten und Schichtdicken,
  • c) bei der Mehrfachnutzung des Bandes und der dabei geforderten räumlichen Präzision; darunter ist die Anordnung von mehreren dicht benachbarten Schreibspuren zu verstehen, wobei eine Schreibspur für den bildmäßigen Transfer benötigt wird. Die thermische Stabilität des Substrats garantiert im Falle der Mehrfachnutzung die Maßhaltigkeit des Bandes auch nach bereits erfolgten Transfervorgängen.
    • Thermal dimensional stability of the substrate layer is required above all in the following processes:
  • a) in the manufacture, storage and transport,
  • b) when the donor layer adheres to the substrate layer in the case of different expansion coefficients and layer thicknesses,
  • c) the multiple use of the tape and the spatial precision required; this means the arrangement of a number of closely adjacent writing tracks, one writing track being required for the pictorial transfer. In the case of multiple use, the thermal stability of the substrate guarantees the dimensional stability of the tape even after transfer processes have already taken place.

    • Das Substrat besteht aus einem Kunststoff, der die vorstehend genannten mechanischen Eigenschaften auch bei einer Temperatur von 150°C oder größer noch aufweist. Daher kommen insbesondere optisch durchsichtige, wärmebeständige und hochfeste Kunststoffe in Betracht. Polypropylen sowie PVCP sind verwendbar. Insbesondere sind die verwendbaren Kunststoffe aber Polyester, Polyaryletheretherketone (PEEK), Polyphenylenether (PPE) und/oder Polycarbonate. Bevorzugt sind Polyester, unter ihnen sind Polyester bevorzugt, die von Dicarbonsäuren und Diolen und/oder von Hydroxycarbonsäuren oder den entsprechenden Lactonen abgeleitet sind, wie Polyethylenterephthalat, Polybutylenterephthalat, Poly-1,4-dimethylolcyclohexanterephthalat und Polyhydroxybenzoate sowie Block-Copolyether-Ester, abgeleitet von Polyethern mit Hydroxylendgruppen und auch Polyester, modifiziert mit Polycarbonaten. Geeignet sind auch Polyethylennaphthalindicarboxylate. Handelsübliche PET-Produkte sind z.B. Hostaphan® und Mylar®.The substrate is made of a plastic that the mechanical properties mentioned above also at a temperature of 150 ° C or greater. Therefore come in particular optically clear, heat-resistant and high-strength plastics. polypropylene and PVCP can be used. In particular, the ones that can be used Plastics but polyester, polyaryl ether ether ketone (PEEK), polyphenylene ether (PPE) and / or polycarbonates. Polyesters are preferred, among them polyesters are preferred, those of dicarboxylic acids and diols and / or of hydroxycarboxylic acids or the corresponding lactones are derived, such as Polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates and block copolyether esters, derived from polyethers with hydroxyl end groups and also polyester, modified with polycarbonates. Polyethylene naphthalenedicarboxylates are also suitable. Commercial PET products are e.g. Hostaphan® and Mylar®.

    Vorzugsweise sollte der Kunststoff für die Substratschicht wenig, vorzugsweise keinen Weichmacher enthalten. Weichmacher sind im wesentlichen von niedermolekularer Natur und können daher bei der Umwandlung der Energie des Laserlichts in Wärme verdampfen und zu einem Plasmaeffekt führen. Auftretendes Plasma reflektiert den eindringenden Laserstrahl, so daß in der Donorschicht die zum Erweichen und Ausstoßen des zu übertragenden Materials erforderliche Wärme nicht mehr erreicht wird. Weichmacher, die bei Einwirkung eines Lasers mit einer Leistung von 300 mJ mit den vorstehend genannten Folien oder Bändern keinen Plasmaeffekt erzeugen, können toleriert werden. Das Gleiche gilt für Konzentrationen üblicher Weichmacher.Preferably, the plastic for the substrate layer should have little preferably contain no plasticizer. Plasticizers are essentially of low molecular nature and can therefore be used in the conversion of the Vaporize the energy of the laser light in heat and lead to a plasma effect. Occurring plasma reflects the penetrating laser beam, so that in the donor layer is used to soften and eject the one to be transferred Material heat required is no longer achieved. Plasticizers that are used Exposure to a laser with a power of 300 mJ with the above Films or tapes that do not produce a plasma effect can be tolerated become. The same applies to concentrations of common plasticizers.

    Für den als Substratschicht zu verwendenden Kunststoff ist eine möglichst hohe optische Transmission erwünscht. Die optische Transmission wird in der Regel durch die Dicke des Bandes und die Auswahl des Materials bestimmt. Außerdem ist die optische Transmission von der Wellenlänge abhängig. Im allgemeinen liegt der Wellenlängenbereich für IR-Halbleiterlaser zwischen 700 und 1600 nm. Vorzugsweise liegen die Bereiche bei 800 bis 900 nm, insbesondere 850 bis 820 nm einerseits und 1000 bis 1200 nm bzw. 1070 bis 1030 nm andererseits. Für einen Nd:YAG-Laser beträgt die Wellenlänge etwa 1064 nm. Die Transmission für die Substratschicht von >70% von IR-Licht ist im Wellenlängenbereich von 700 bis 1600 nm, bevorzugter >85%. Besonders bevorzugt ist eine Transmission von IR-Licht im Wellenlängenbereich von 800 bis 1100 nm von > 85%. Als Laser kann ein punktförmiger Laser verwendet werden. Bevorzugt sind allerdings IR-Halbleiterlaser-Diodenarrays.For the plastic to be used as the substrate layer, one is optical transmission as high as possible is desirable. The optical transmission is usually determined by the thickness of the tape and the choice of material certainly. In addition, the optical transmission depends on the wavelength. In general, the wavelength range for IR semiconductor lasers is between 700 and 1600 nm. The ranges are preferably 800 to 900 nm, in particular 850 to 820 nm on the one hand and 1000 to 1200 nm or 1070 to 1030 nm on the other hand. For an Nd: YAG laser, the wavelength is approximately 1064 nm. The transmission for the substrate layer of> 70% IR light is in the wavelength range from 700 to 1600 nm, more preferably> 85%. Transmission of IR light in the wavelength range is particularly preferred from 800 to 1100 nm from> 85%. A point laser can be used as the laser be used. However, IR semiconductor laser diode arrays are preferred.

    Wie vorstehend erwähnt, muß das Substrat chemisch inert sein, d.h. die Chemikalien, die beim Herstellungsverfahren des Thermotransferbandes eingesetzt werden, dürfen das Substrat nicht nachteilig beeinflussen. Insbesondere sind dies organische Lösemittel, vorzugsweise Ketone, aliphatische und cycloaliphatische Kohlenwasserstoffe sowie Säuren und Basen.As mentioned above, the substrate must be chemically inert, i.e. the chemicals used in the manufacturing process of the thermal transfer ribbon are used, must not adversely affect the substrate. In particular these are organic solvents, preferably ketones, aliphatic and cycloaliphatic hydrocarbons as well as acids and bases.

    Wird eine Folie in Bandform verwendet, so beläuft sich die Breite des Bandes auf 3 mm bis 50 mm, vorzugsweise 8 mm bis 30 mm, bevorzugt 10 mm bis 15 mm.If a film in tape form is used, the width of the Tape on 3 mm to 50 mm, preferably 8 mm to 30 mm, preferably 10 mm up to 15 mm.

    Der wärmeempfindliche und/oder laserempfindliche StoffThe heat sensitive and / or laser sensitive material

    Nachdem der Laserstrahl die Substratschicht durchdrungen hat, trifft er auf die Donorschicht, d.h. die Schicht mit der zu übertragenden Masse. An der Grenzschicht zwischen der Substratschicht und der Donorschicht soll in möglichst kurzer Zeit Lichtenergie in Wärmeenergie umgewandelt werden. Dazu ist es erforderlich, daß das zu übertragende Polymer einen Hilfsstoff enthält, der diesen Vorgang unterstützt. Insbesondere sind dies Stoffe, die die Energie der Lichtstrahlung insbesondere der vorgenannten Wellenlängenbereiche besonders gut absorbieren und in Wärmeenergie umwandeln. Diese Stoffe können organische Farbstoffe oder organische Färbemittel sein, unter der Maßgabe, daß sie sich bei Umwandlung von Lichtenergie in Wärmeenergie nicht zersetzen. Beispiele besonders stabiler organischer Farbstoffe oder Pigmente sind Benzothiazole, Chinoline, Cyaninfarbstoffe oder -pigmente, Perylenfarbstoffe oder -pigmente, Polymethinfarbstoffe und -pigmente, wie Oxonolfarbstoffe und - pigmente und Merocyaninfarbstoffe und -pigmente. Handelsübliche organische Farbstoffe oder Pigmente sind: KF 805 PINA von Riedl de Haen (eine Benzothiazolverbindung), KF 810 PINA von Riedl de Haen (eine Chinolinverbindung), ADS840MI, ADS840MT, ADS840AT, ADS890MC, ADS956BI, ADS800WS, ADS96HO von American Dye Source Inc., 3,3'-Diethylthiatricarbocyanin-p-toluolsulfonat (Cyaninfarbstoffverbindungen), Perylen-3,4,8,10-tetracarbonsäureanhydrid (eine Perylenverbindung) sowie Epolite V-63 und Epolite III-178 von Epolin Inc., Newmark. Die organischen Farbstoffe oder Pigmente werden in einer Menge von 5 bis 40 Gew.-%, vorzugsweise 10 bis 30 Gew.-%, der Trockenmasse der Donorschicht eingesetzt Diese Farbstoffe können einzeln oder im Gemisch angewendet werden, um das Absorptionsmaximum in den Wellenlängenbereich des eingesetzten Lasers zu verschieben.After the laser beam has penetrated the substrate layer, hits he on the donor layer, i.e. the layer with the mass to be transferred. On the boundary layer between the substrate layer and the donor layer is said to be in light energy can be converted into heat energy as short as possible. To it is necessary that the polymer to be transferred contains an auxiliary, who supports this process. In particular, these are substances that make up energy the light radiation especially the aforementioned wavelength ranges in particular absorb well and convert into thermal energy. These substances can organic dyes or organic coloring agents, provided that that they do not decompose when light energy is converted into heat energy. Examples of particularly stable organic dyes or pigments are Benzothiazoles, quinolines, cyanine dyes or pigments, perylene dyes or pigments, polymethine dyes and pigments, such as oxonol dyes and - pigments and merocyanine dyes and pigments. Commercial organic Dyes or pigments are: KF 805 PINA from Riedl de Haen (a benzothiazole compound), KF 810 PINA from Riedl de Haen (a quinoline compound), ADS840MI, ADS840MT, ADS840AT, ADS890MC, ADS956BI, ADS800WS, ADS96HO from American Dye Source Inc., 3,3'-diethylthiatricarbocyanine p-toluenesulfonate (Cyanine dye compounds), perylene-3,4,8,10-tetracarboxylic anhydride (a perylene compound) as well as Epolite V-63 and Epolite III-178 from Epolin Inc., Newmark. The organic dyes or pigments are in an amount of 5 to 40 wt .-%, preferably 10 to 30 wt .-%, the dry mass of the donor layer used. These dyes can be used individually or applied in a mixture to the absorption maximum in to shift the wavelength range of the laser used.

    Neben organischen Farbstoffen oder organischen Färbemitteln sind anorganische Stoffe von Interesse, insbesondere jene, die sich bei der Umwandlung von Lichtenergie in Wärmeenergie nicht zersetzen. Derartige Stoffe sind beispielsweise Titandioxid, Aluminiumoxid und weitere Metalloxide und anorganische Farbpigmente. Zu nennen sind hier Magnetit: Fe3O4; Spinellschwarz: Cu(Cr,Fe)2O4, Co(Cr,Fe)2O4; Manganferrit: MnFe2O4. Diese Stoffe werden in einer Menge bis zu 20 Gew.-% eingesetzt.In addition to organic dyes or organic colorants, inorganic substances are of interest, in particular those which do not decompose when light energy is converted into heat energy. Such substances are, for example, titanium dioxide, aluminum oxide and other metal oxides and inorganic color pigments. Magnetite can be mentioned here: Fe 3 O 4 ; Spinel black: Cu (Cr, Fe) 2 O 4 , Co (Cr, Fe) 2 O 4 ; Manganese ferrite: MnFe 2 O 4 . These substances are used in an amount of up to 20% by weight.

    Eine Sonderstellung für Stoffe, die effektiv Lichtenergie in Wärmeenergie umwandeln können, spielt Ruß. Durch das Herstellungsverfahren läßt sich Ruß besonders günstig beeinflussen. Insbesondere fein verteilter Ruß mit einer mittleren Teilchengröße zwischen 10 und 50 nm, insbesondere zwischen 13 und 30 nm und/oder mit einer Schwarzzahl nach DIN 55979 zwischen 200 und 290, insbesondere von 250, kann vorteilhaft eingesetzt werden. Ruße werden in einer Menge bis zu 30 Gew.-%, vorzugsweise bis zu 20 Gew.-%, eingesetzt. Die vorstehend genannten Stoffe, nämlich organische Farbstoffe oder Färbemittel, anorganischer Stoff, der sich bei der Umwandlung von Lichtenergie in Wärmeenergie nicht zersetzt, und Ruß können einzeln oder im Gemisch verwendet werden. Die Menge des wärmeempfindlichen und/oder laserlichtempfindlichen Stoffes hängt von der Fähigkeit der Umwandlung von Lichtenergie in ausreichend Wärmeenergie zur Übertragung des auf der Substratschicht befindlichen zu übertragenden Stoffes ab.A special position for substances that effectively use light energy in thermal energy can convert, plays soot. Through the manufacturing process affect soot particularly favorably. Especially finely divided soot with an average particle size between 10 and 50 nm, in particular between 13 and 30 nm and / or with a black number according to DIN 55979 between 200 and 290, in particular of 250, can be used advantageously. Become soot in an amount of up to 30% by weight, preferably up to 20% by weight. The aforementioned substances, namely organic dyes or Colorant, inorganic substance involved in the conversion of light energy not decomposed in thermal energy, and soot can be used individually or in a mixture become. The amount of heat sensitive and / or laser sensitive Substance depends on the ability to convert light energy into sufficient thermal energy to transfer that located on the substrate layer to be transferred.

    Das Polymer der DonorschichtThe polymer of the donor layer

    Das Polymer der Donorschicht übt insbesondere folgende Funktionen aus. Zum einen wird es unter Einwirkung des Laserstrahls rasch erweichen, an der Grenzfläche der Substratschicht den erforderlichen Druck entwikkeln und als halbfester Pfropf auf den Druckformzylinder übertragen. Dort haftet der so übertragene Kunststoff aufgrund hydrophiler Gruppen an der hydrophilen Oberfläche des Druckformzylinders. Schließlich sollte das Polymer zunächst einen Fixierschritt durch Erwärmen und dann einen Hydrophilierungsschritt des fertigen Druckformzylinders überstehen. Bei diesem Schritt werden die freien Metallflächen des Druckformzylinders hydrophiliert und die Kunststoffbereiche auf dem Druckformzylinder profiliert. Außerdem sollte der nun auf dem Druckformzylinder befindliche Kunststoff, Druckfarbe annehmen können und eine möglichst hohe Standzeit aufweisen. Schließlich soll nach erfolgtem Druckvorgang in einfacher Weise umweltschonend, d.h. möglichst mit einer wässerigen nichttoxischen Lösung, die übertragene Masse von dem Druckformzylinder abgespült werden, so daß diese für den nächsten Vorgang in sehr kurzer Zeit wieder zur Verfügung steht. Das Polymer ist bei einem pH-Wert größer 10 in wäßriger Lösung löslich, aber unlöslich in dem Feuchtwasser, das normalerweise beim Offset-Papierdruck verwendet wird. Dies wird dadurch erreicht, daß man das Polymer für einen vom Feuchtwasser abweichenden pH-Wert größer 10 wasserlöslich gestaltet. Bevorzugt ist ein alkalischer Bereich mit einem pH-Wert größer 10,5, insbesondere größer 11.The polymer of the donor layer performs the following functions in particular out. Firstly, it will soften quickly under the influence of the laser beam, develop the required pressure at the interface of the substrate layer and transferred to the printing form cylinder as a semi-solid graft. Is liable there the plastic thus transferred due to hydrophilic groups on the hydrophilic Surface of the printing form cylinder. Finally, the polymer should be first a fixing step by heating and then a hydrophilization step of the survive the finished printing form cylinder. In this step, the free ones Metal surfaces of the printing form cylinder hydrophilized and the plastic areas profiled on the printing form cylinder. In addition, it should now be on the printing form cylinder plastic, printing ink and a have the longest possible service life. Finally, after printing is done in a simple way environmentally friendly, i.e. if possible with an aqueous non-toxic solution, the transferred mass rinsed from the printing form cylinder be so that for the next operation in a very short time is available again. The polymer is aqueous at a pH greater than 10 Solution soluble but insoluble in the fountain solution that is normally used in Offset paper printing is used. This is achieved in that the polymer is water-soluble for a pH greater than 10 deviating from the fountain solution designed. An alkaline range with a pH is preferred greater than 10.5, in particular greater than 11.

    Damit das Polymer von dem Substrat oder Träger 1 abgelöst werden kann, sollte sein Zahlenmittel des Molekulargewichts vorzugsweise 20000 nicht übersteigen. Andererseits sollte sein Zahlenmittel des Molekulargewichts vorzugsweise 1000 nicht unterschreiten, da sonst keine ausreichende Wasserbeständigkeit erreicht wird. Vorzugsweise liegt der Bereich zwischen 1000 und 15000, insbesondere zwischen 1000 und 10000. So that the polymer can be detached from the substrate or carrier 1 can, its number average molecular weight should preferably not be 20,000 exceed. On the other hand, its number average molecular weight should be preferred Do not fall below 1000, otherwise there is insufficient water resistance is achieved. The range is preferably between 1000 and 15,000, especially between 1,000 and 10,000.

    Die Polymere müssen Druckfarbe annehmen. Hierfür ist eine Oberflächenspannung vorzugsweise zwischen 50 und 10 mN/m, insbesondere zwischen 40 und 23 mN/m, besonders bevorzugt im Bereich von 28 und 32 mN/m, von Bedeutung. Die Messung der Oberflächenspannung erfolgt über Randwinkelmessung mit 3 + n Testflüssigkeiten und wird nach Wendt, Own und Rabel ausgewertet.The polymers have to accept printing ink. For this there is a surface tension preferably between 50 and 10 mN / m, in particular between 40 and 23 mN / m, particularly preferably in the range of 28 and 32 mN / m, significant. The surface tension is measured via contact angle measurement with 3 + n test liquids and is according to Wendt, Own and Rabel evaluated.

    Damit das übertragene Polymer an dem hydrophilen Druckformzylinder ausreichend haftet, weist es saure Gruppen auf. Diese Gruppen können ausgewählt sein aus den Gruppen -COOH, -SO3H, -OSO3H und -OPO3H2 sowie den gegebenenfalls Alkyl- oder Aryl-substituierten Amiden davon. Die Alkylgruppe kann 1 bis 6, vorzugsweise 1 bis 4, Kohlenstoffatome aufweisen, die Arylgruppe kann 6 bis 10, vorzugsweise 6, Kohlenstoffatome aufweisen. Vorzugsweise enthält das Polymer außerdem eine aromatische Gruppe. Bevorzugt sind Phenylgruppen. Das Polymer stammt vorzugsweise aus der Polymerisation von α,β-ungesättigten Carbon-, Sulfon-, Schwefel- und Phosphorsäuren oder -estern oder deren vorstehend definierten Amiden und Styrol sowie dessen Derivaten und gegebenenfalls α,β-ungesättigten Carbonsäureestern. Die Auswahl der sauren Monomere sowie der aromatisch vinylischen Monomere sollte so erfolgen, daß das Polymer eine Glasübergangstemperatur Tg zwischen 30 und 100°C, insbesondere 30 und 90°C, vorzugsweise zwischen 55 und 65°C, aufweist. Das Polymer weist vorzugsweise eine Ceiling-Temperatur im Bereich des Schmelzpunkts auf, wobei der Schmelzbereich zwischen 80 und 150, insbesondere 90 und 140, vorzugsweise 105 bis 115°C, besonders bevorzugt um 110°C, liegt. Als wenig vorteilhaft erwiesen sich Copolymerisate, die wesentliche Anteile an α-Methylstyrol enthielten.In order for the transferred polymer to adhere sufficiently to the hydrophilic printing form cylinder, it has acidic groups. These groups can be selected from the groups -COOH, -SO 3 H, -OSO 3 H and -OPO 3 H 2 as well as the optionally alkyl- or aryl-substituted amides thereof. The alkyl group can have 1 to 6, preferably 1 to 4, carbon atoms, the aryl group can have 6 to 10, preferably 6, carbon atoms. Preferably the polymer also contains an aromatic group. Phenyl groups are preferred. The polymer preferably originates from the polymerization of α, β-unsaturated carboxylic, sulfonic, sulfuric and phosphoric acids or esters or their amides and styrene as defined above, and also their derivatives and optionally α, β-unsaturated carboxylic esters. The acidic monomers and the aromatic vinyl monomers should be selected such that the polymer has a glass transition temperature T g between 30 and 100 ° C., in particular 30 and 90 ° C., preferably between 55 and 65 ° C. The polymer preferably has a ceiling temperature in the range of the melting point, the melting range being between 80 and 150, in particular 90 and 140, preferably 105 to 115 ° C., particularly preferably around 110 ° C. Copolymers which contained substantial amounts of α-methylstyrene proved to be less advantageous.

    Geignete Polymere findet man in US-A-4 013 607, US-A-4 414 370 sowie in US-A-4 529 787. Dort offenbarte Harze können z.B. im wesentlichen vollständig gelöst werden, wenn ein ausreichender Teil, beispielsweise 80-90 %, dieser Gruppen mit einer wäßrigen Lösung basischer Stoffe, wie Borax, Amine, Ammoniumhydroxid, NaOH und/oder KOH neutralisiert wird. Z.B. würde ein Styrol-Acrylsäure-Harz mit einer Säurezahl von etwa 190 nicht weniger als etwa 0,0034 Äquivalente -COOH - Gruppen pro Gramm Harz enthalten und würde im wesentlichen vollständig gelöst werden, wenn ein Minimum von etwa 80-90 % der -COOH - Gruppen durch eine wäßrige alkalische Lösung neutralisiert werden. Die Säurezahl kann im Bereich zwischen 120 und 550, 150 und 300, z.B. 150 bis 250 liegen. Die nachstehend angeführten Kombinationen von Monomeren sind bevorzugt Styrol-Acrylsäure, Styrol-Maleinsäureanhydrid, Methylmethacrylat-Butylacrylat-Methacrylsäure, α-Methylstyrol/Styrol-Ethylacrylat-Acrylsäure, Styrol-Butylacrylat-Acrylsäure, Styrol-Methylacrylat-Butylacrylat-Methylacrylsäure. Ein alkalilösliches Harz mit 68 % Styrol/ 32 % Acrylsäure mit einem Molekulargewicht von 500-10000 kann erwähnt werden. Andere Harze weisen eine Säurezahl von etwa 200 und ein Molekulargewicht von etwa 1400 auf. Im allgemeinen weisen Styrol(α-Methylstyrol)-Acrylsäure-(Acrylsäureester)-Harze ein zahlenmittleres Molekulargewicht von 2500-4500 und ein gewichtsmittleres Molekulargewicht von 6500-9500 auf. Die Säurezahl liegt bei 170-200. Beispielhafte Polymere weisen 60-80 Gew.-% aromatische Monoalkenylmonomere und 40-20 Gew.-% (Meth)acrylsäuremonomere und gegebenenfalls 0-20 Gew.-% keine Carboxylgruppen enthaltendes Acrylmonomer auf. Gemische von 10:1 bis 1:2 oder 1:1, vorzugsweise 8:1 bis 1:2, zum Beispiel 2:1 bis 1:2 Styrol/α-Methylstyrol können eingesetzt werden. Als wenig vorteilhaft erwiesen sich allerdings Copolymerisate, die wesentliche Anteile an α-Methylstyrol enthielten.Suitable polymers can be found in US-A-4 013 607, US-A-4 414 370 and in U.S.-A-4,529,787. Resins disclosed therein can e.g. essentially be completely solved if a sufficient part, for example 80-90 % of these groups with an aqueous solution of basic substances such as borax, Amines, ammonium hydroxide, NaOH and / or KOH is neutralized. For example, would a styrene-acrylic acid resin with an acid number of about 190 not less than contain about 0.0034 equivalents of -COOH groups per gram of resin and would essentially be solved completely if a minimum of about 80-90% of the -COOH groups neutralized by an aqueous alkaline solution become. The acid number can range between 120 and 550, 150 and 300, e.g. 150 to 250 lie. The combinations of Monomers are preferably styrene-acrylic acid, styrene-maleic anhydride, Methyl methacrylate-butyl acrylate-methacrylic acid, α-methylstyrene / styrene-ethyl acrylate-acrylic acid, Styrene-butyl acrylate-acrylic acid, styrene-methyl acrylate-butyl acrylate-methyl acrylic acid. An alkali-soluble resin with 68% styrene / 32% acrylic acid with a molecular weight of 500-10000 can be mentioned. Other Resins have an acid number of about 200 and a molecular weight of about 1400. In general, styrene (α-methylstyrene) acrylic acid (acrylic acid ester) resins a number average molecular weight of 2500-4500 and a weight average molecular weight of 6500-9500. The acid number is included 170-200. Exemplary polymers have 60-80% by weight of aromatic monoalkenyl monomers and 40-20% by weight of (meth) acrylic acid monomers and optionally 0-20% by weight of acrylic monomer containing no carboxyl groups. Mixtures from 10: 1 to 1: 2 or 1: 1, preferably 8: 1 to 1: 2, for example 2: 1 up to 1: 2 styrene / α-methylstyrene can be used. Not very advantageous However, copolymers have been found to contain substantial amounts of α-methylstyrene contained.

    Das für das Verfahren verwendete Thermotransferband weist ein Beschichtungsgewicht im Bereich von 0,8 bis 5 g/m2 +/- 0,2 auf und bevorzugt liegt dieses im Bereich von 1,6 bis 2,0 g/m2.The thermal transfer ribbon used for the method has a coating weight in the range from 0.8 to 5 g / m 2 +/- 0.2 and is preferably in the range from 1.6 to 2.0 g / m 2 .

    Die BenetzungshilfeThe wetting aid

    Der Benetzungshilfe kommen verschiedene Funktionen zu. Die Benetzungshilfe liegt nach dem Übertragen auch am Grenzbereich zwischen Metalloberfläche und übertragenem Polymer vor, so daß dort die Haftung erhöht wird. Schließlich glättet sie beim Fixieren, d.h. bei einem nachträglichen Erwärmen des übertragenen Polymers, die Oberfläche des übertragenen Polymers, so daß die Struktur des Bildpunktes verbessert wird. Die Benetzungshilfe wird ausgewählt aus Lösemitteln, wie Alkohole, Ketone, Ester der Phosphorsäure, Glykolether und anionische Tenside, insbesondere Alkohole und Ketone, bevorzugt Ketone, besonders bevorzugt Methylethylketon. Handelsprodukte der vorgenannten Lösemittel sind DEGDEE, DEGBBE von BASF als Vertreter der Glykolether und Arylalkylsulfonsäuren als Vertreter der anionischen Tenside oder aliphatische Ester von Orthophosphorsäure, wie Etingal. Vorzugsweise stammen die als Benetzungshilfe dienenden Lösemittel aus dem Herstellungsschritt des Thermotransferbandes.The wetting aid has various functions. The wetting aid lies after the transfer also at the border area between the metal surface and transferred polymer, so that there increases the adhesion becomes. Finally, it smoothes when fixing, i.e. with a subsequent heating of the transferred polymer, the surface of the transferred polymer, so that the structure of the pixel is improved. The wetting aid will selected from solvents such as alcohols, ketones, esters of phosphoric acid, Glycol ethers and anionic surfactants, especially alcohols and ketones, are preferred Ketones, particularly preferably methyl ethyl ketone. Commercial products of The aforementioned solvents are DEGDEE, DEGBBE from BASF as a representative of Glycol ethers and arylalkylsulfonic acids as representatives of the anionic surfactants or aliphatic esters of orthophosphoric acid, such as etingal. Preferably The solvents used as a wetting aid originate from the manufacturing step of the thermal transfer ribbon.

    Benetzungshilfen können in geringen Mengen (z.B. 0,05-8 Gew.-%, vorzugsweise 0,5-5 Gew.-% der Trockenmasse der Donorschicht) durch den Herstellungsvorgang eingebracht werden. Ein weiterer Vorteil des Vorliegens einer Benetzungshilfe ist eine intrinsische Temperaturregelung beim Transfervorgang und bei der thermischen Nachbehandlung. Über die Eigenschaften Siedepunkt, -bereich, Verdampfungsenthalpie und Wärmekapazität wird bei beiden Vorgängen für das nötige Zeitfenster eine maximale obere Grenztemperatur definiert. Beispielsweise können mikroskopische Desorptionsvorgänge im Falle einer auf Ruß basierenden Formulierung eine obere Grenztemperatur vorgeben. Eine Überhitzung der übertragenen Masse kann sowohl durch die externe Regelung der Wärmequellen als auch durch die Zusammensetzung der Masse selbst beeinflußt werden und schafft damit eine hohe Sicherheit bei der Verfahrensführung.Wetting aids can be used in small amounts (e.g. 0.05-8% by weight, preferably 0.5-5% by weight of the dry mass of the donor layer) by the Manufacturing process are introduced. Another advantage of being present A wetting aid is an intrinsic temperature control during the transfer process and thermal post-treatment. About the properties Boiling point, range, enthalpy of vaporization and heat capacity are at a maximum upper limit temperature for both processes for the necessary time window Are defined. For example, microscopic desorption processes in the In the case of a formulation based on carbon black, an upper limit temperature pretend. Overheating of the transferred mass can be caused by both external control of the heat sources as well as by the composition of the Mass itself can be influenced and thus creates a high level of security in the Process management.

    Das VerfahrenThe procedure

    Die Herstellung des Thermotransferbandes erfolgt in üblicher Weise. Insbesondere werden der wärmeempfindliche oder laserlichtempfindliche Stoff, das Polymer und gegebenenfalls eine Benetzungshilfe sowie ein Lösemittel, wobei letztere identisch sein können, sorgfältig und homogen vermischt. Die Masse wird dann mit einem Meyer-Bar oder nach dem Gravurverfahren aufgetragen. Die Dicke der Übertragungsschicht beträgt 0,5 bis 5 µm, vorzugsweise 0,8 bis 4 µm, insbesondere 1 bis 3 µm, bevorzugt 1,5 bis 2,5 µm, Trockenschichtdicke. Nach dem Verdampfen des Lösemittels wird das Band auf eine Spule gewickelt und in eine Bandstation eingesetzt.The thermal transfer ribbon is produced in the usual way. In particular, the heat-sensitive or laser-sensitive substance, the polymer and optionally a wetting aid and a solvent, the latter being identical, carefully and homogeneously mixed. The Mass is then applied with a Meyer bar or by the engraving process. The thickness of the transfer layer is 0.5 to 5 µm, preferably 0.8 to 4 µm, in particular 1 to 3 µm, preferably 1.5 to 2.5 µm, dry layer thickness. After evaporation of the solvent, the tape is on a Coil wound and inserted in a tape station.

    Die Funktion der erfindungsgemäßen ThermotransferfolieThe function of the thermal transfer film according to the invention

    Die Bildpunktübertragungseinheit (ein punktförmiger Laser oder ein Halbleiterlaserdiodenarray) empfängt von einem Datenspeicher Daten für die Bebilderung des Druckformzylinders. Das Thermotransferband bewegt sich mit Hilfe einer Bandstation relativ zu einem während des Übergangsvorgangs sich selbst aber unabhängig bewegenden Druckzylinder. Diese Relativgeschwindigkeit und die zeitliche Abfolge der Daten steuert die Abbildung auf dem Druckzylinder. Die eingestrahlte Lichtenergie wird in Wärmeenergie umgewandelt, welche an der Grenzschicht zwischen Substratschicht und Donorschicht des Thermotransferbandes einen besonders starken Temperaturanstieg verursacht. Durch diesen Temperaturanstieg werden an der vorstehend genannten Grenzschicht Gase erzeugt, die das nun erweichte Material der Donorschicht gegen das Metall des Druckformzylinders schleudern. Die Substanzteile des übertragenen Materials markieren auf der Oberfläche des Druckformzylinders aufgrund ihrer oleophilen Eigenschaft beim späteren Druck die farbführenden Bereiche.The pixel transmission unit (a point laser or a Semiconductor laser diode array) receives data for the from a data memory Illustration of the printing form cylinder. The thermal transfer ribbon moves with it Help a tape station relative to yourself during the transition process itself but independently moving pressure cylinder. This relative speed and the chronological sequence of the data controls the mapping on the printing cylinder. The radiated light energy is converted into thermal energy, which at the interface between the substrate layer and the donor layer of the Thermal transfer ribbon causes a particularly sharp rise in temperature. This increase in temperature causes the above-mentioned boundary layer Generates gases that counter the now softened material of the donor layer spin the metal of the printing form cylinder. The substance parts of the transferred Mark material on the surface of the printing form cylinder due to the oleophilic property of the ink-guiding areas during later printing.

    Meßverfahrenmeasurement methods

  • a) Das Verhalten eines Polymers der Donorschicht in wässriger alkalischer Lösung wird durch nachstehendes Untersuchungsverfahren charakterisiert:
  • 1g Polymer wird in einer wässrigen alkalischen Lösung gelöst. Zum Lösen werden die in der Tabelle aufgeführten Mengen an Lauge benötigt: Lauge in g bis zum vollständigen Auflösen pH-Wert Polymer in 0,5 mol/l KOH 10 13 Polymer in 0,1 mol/l NaOH 50 11 Polymer in 0,3 mol/l NaOH 20 13
  • In der vorliegenden Tabelle wurde das Polymer J682 der Fa. Johnson S.A. Polymer eingesetzt.
    • a) The behavior of a polymer of the donor layer in aqueous alkaline solution is characterized by the following test method:
  • 1g of polymer is dissolved in an aqueous alkaline solution. The amounts of alkali listed in the table are required to dissolve: Lye in g until completely dissolved PH value Polymer in 0.5 mol / l KOH 10 13 Polymer in 0.1 mol / l NaOH 50 11 Polymer in 0.3 mol / l NaOH 20 13
  • Polymer J682 from Johnson SA Polymer was used in the present table.
  • b) Die Randwinkelmessung erfolgt mit 3+n Testflüssigkeiten. Die Auswertung wird dann nach Wendt, Own und Rabel vorgenommen. Erhalten wird die statische Oberflächenspannung.b) The contact angle measurement is carried out with 3 + n test liquids. The Evaluation is then carried out according to Wendt, Own and Rabel. Receive becomes the static surface tension.
  • c) Die Messung der Glasübergangstemperatur, des Schmelzbereichs und die Bestimmung der Ceiling-Temperatur wurde mit einem DSC-Gerät der Fa. Mettler Toledo, DSC30/TSC10A/TC15 mit einem 150 µl-Aluminiumbecher, der 20-30 mg Polymer enthält, ausgeführt. Eine Temperaturrate von 10-20°C/min wurde verwendet. Folgendes Temperaturprogramm wurde genutzt: Beginn bei mindestens 70 Grad unter der zu erwartenden Tg und Ende bei etwa 50 Grad oberhalb der zu erwartenden Tg oder bei 180°C, um Zersetzung zu verhindern.c) The measurement of the glass transition temperature, the melting range and the determination of the ceiling temperature was carried out with a DSC device Mettler Toledo, DSC30 / TSC10A / TC15 with a 150 µl aluminum beaker, containing 20-30 mg of polymer. A temperature rate of 10-20 ° C / min was used. The following temperature program was used: Start at least 70 degrees below the expected Tg and end at about 50 degrees above the expected Tg or at 180 ° C to decompose prevent.

    • Die vorliegende Erfindung wird durch das nachstehende Beispiel genauer erläutert. Prozent-, Verhältnis- und Teilangaben sind auf das Gewicht bezogen, sofern nicht anders ausgewiesen.The present invention is illustrated by the example below explained. Percentages, ratios and parts are by weight unless otherwise stated.

    Beispielexample

    Eine Polyethylenterephthalatfolie (PET) Hostaphan® der Fa. Hoechst mit einer Dicke von 7,5 µm wird mit einem Meyer-Bar mit einer Masse nachstehender Zusammensetzung zu einem Trockenschichtgewicht von 1,8 g/m2 beschichtet.A polyethylene terephthalate film (PET) Hostaphan® from Hoechst with a thickness of 7.5 μm is coated with a Meyer bar with a mass of the following composition to a dry layer weight of 1.8 g / m 2 .

    20 % Ruß mit einer Schwarzzahl nach DIN 55797 von 250 und 80 % Polymer J682 von Johnson S.A. Polymer und eine zur Herstellung einer streichfähigen Masse ausreichende Menge Methylethylketon werden angemischt. Die Masse wird mit einem Meyer-Bar zu dem vorstehend genannten Trockenschichtgewicht auf die Polyesterfolie aufgetragen. Nach dem Auftragen wird die Folie getrocknet Im Falle eines Bandes mit einer Breite von beispielsweise 12 mm wird dieses auf eine Spule gewickelt und in eine Bandstation, z.B. eine Vorrichtung wie in EP-B-0 698 488 beschrieben, eingesetzt. Mit einem IR-Halbleiterlaserarray wird die Rückseite des so hergestellten Thermotransferbandes bestrahlt. Dabei werden gleichzeitig mehrere Kunststoffteilchen von dem Thermotransferband auf den Druckformzylinder bildmäßig übertragen. Mit dem so bebilderten Druckzylinder konnten 20 000 Exemplare bedruckt werden.20% carbon black with a black number according to DIN 55797 of 250 and 80% Polymer J682 from Johnson S.A. Polymer and one for making one Spreadable mass sufficient amount of methyl ethyl ketone are mixed. The mass is added to the above with a Meyer bar Dry layer weight applied to the polyester film. After application the film is dried. In the case of a tape with a width of, for example 12 mm this is wound on a spool and in a tape station, e.g. a device as described in EP-B-0 698 488 is used. With an IR semiconductor laser array becomes the back of the thermal transfer ribbon thus produced irradiated. Several plastic particles from transfer the thermal transfer ribbon to the printing form cylinder. With The printing cylinder illustrated in this way could print 20,000 copies.

    Claims (23)

    1. A thermal-transfer film comprising a substrate layer and, applied thereon, a donor layer, characterised in that
      a) the substrate layer consists of at least one polymeric composition that exhibits at least the following properties:
      mechanical stability at a temperature > 150 °C; transmission > 70 % in respect of light having a wavelength from 700 nm to 1600 nm;
      b) the donor layer comprises at least the following components:
      i) a substance that is able to convert the radiant energy of incident laser light into thermal energy,
      ii) a polymer that comprises acid groups and/or the optionally substituted amide groups thereof and that at a pH value greater than 10 dissolves in water but not in the fountain solution and
      iii) optionally a wetting aid.
    2. Thermal-transfer film according to Claim 1, wherein the substrate layer exhibits a thickness from 50 µm to 4 µm, a tensile strength at break greater than 270 N/mm2 in the machine direction and greater than 180 N/mm2 in the transverse direction, and a thermal shrinkage at 150 °C of less than 5%.
    3. Thermal-transfer film according to Claim 1 or Claim 2, wherein the polymeric composition is a polyester, a polyaryl ether ether ketone, a polyphenylene ether and/or a polycarbonate.
    4. Thermal-transfer film according to Claim 3, wherein the polyester is selected from polyesters that are derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones; such as polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate, polyhydroxy benzoates and polyethylene naphthalene dicarboxylates; and also block copolyether esters, derived from polyethers with hydroxyl terminal groups and polyesters, modified with polycarbonates.
    5. Thermal-transfer film according to Claim 4, wherein the polyester is a polyethylene terephthalate.
    6. Thermal-transfer film according to one of Claims 1 to 5, wherein component i) is
      a) an organic dye or an organic colouring agent having at least the following properties:
      aa) absorption maximum within the wavelength range from 700 nm to 1600 nm,
      ab) stability at a temperature greater than 150 °C
         and/or
      b) an inorganic substance that is able to convert radiant energy into thermal energy without decomposing,
      and/or
      c) a type of carbon.
    7. Thermal-transfer film according to Claim 6, wherein the organic dye or the organic colouring agent comprises thermostable organic dyes or pigments selected from benzothiazoles, quinolines, cyanine dyes or pigments, perylene dyes or pigments and polymethine dyes or pigments, such as oxonol dyes and pigments or merocyanine dyes and pigments.
    8. Thermal-transfer film according to Claim 6, wherein the inorganic dye or the inorganic pigment is selected from TiO2, Al2O3, magnetite Fe3O4; spinel black: Cu(Cr,Fe)2O4, Co(Cr,Fe)2O4 and manganese ferrite MnFe2O4.
    9. Thermal-transfer film according to Claim 6, wherein the carbon is selected from a carbon black having a mean particle size from 5 nm to 100 nm.
    10. Thermal-transfer film according to Claim 9, wherein the carbon black has a blackness value according to DIN 55979 between 200 and 290.
    11. Thermal-transfer film according to one of Claims 1 to 10, wherein the polymer ii) exhibits acid groups selected from -COOH, -SO3H, -OSO3H and -OPO3H2 and/or optionally from the amide groups thereof substituted with C1-C6 alkyl residues or C6-C10 aryl residues.
    12. Thermal-transfer film according to one of Claims 1 to 11, wherein the polymer exhibits a number-average molecular weight from 1000 to 20000.
    13. Thermal-transfer film according to one of Claims 1 to 12, wherein the applied polymer exhibits a surface tension from 50 mN/m to 20 mN/m, ascertained by contact-angle measurement.
    14. Thermal-transfer film according to one of Claims 1 to 13, wherein the polymer exhibits a glass transition temperature within the range from 30 °C to 100 °C.
    15. Thermal-transfer film according to one of Claims 1 to 14, wherein the polymer exhibits a ceiling temperature within the melting-point range for all components between 80 °C and 150 °C.
    16. Thermal-transfer film according to one of Claims 1 to 15, wherein the optionally present wetting aid iii) is selected from organic solvents that are capable of dissolving component ii).
    17. Thermal-transfer film according to Claim 16, wherein the solvent is a ketone, in particular methyl ethyl ketone.
    18. Thermal-transfer film according to Claim 16 or 17, wherein the solvent is present in a quantity that is sufficient in order that, after transfer of the polymer of the donor layer to the printing forme, in the course of a fixing step subject to the influence of heat the evaporation of the solvent over the period of the influence of heat results in an intrinsic temperature control.
    19. Thermal-transfer film according to one of Claims 1 to 18, in the form of a ribbon having a width within the range from 3 mm to 50 mm.
    20. A process for producing a thermal-transfer film according to one of Claims 1 to 19, wherein a substance i) that is able to convert the radiant energy of incident laser light into thermal energy, a polymer ii) that comprises acid groups and/or the optionally substituted amide groups thereof and that at a pH value greater than 10 dissolves in water but not in the fountain solution, and optionally a wetting aid iii) as well as a solvent, the latter components possibly being identical, are carefully and homogeneously mixed, the composition is then applied onto a substrate layer with a Meyer bar or in accordance with an engraving process, the thickness of the transfer layer amounting to 0.5 µm to 5 µm dry thickness, and the solvent is then evaporated until substantial hardening of the applied composition occurs.
    21. A composition of the donor layer according to Claim 1, comprising
      i) a substance that is able to convert the radiant energy of incident laser light into thermal energy,
      ii) a polymer that comprises acid groups and/or the optionally substituted amide groups thereof and that at a pH value greater than 10 dissolves in water but not in the fountain solution and
      iii) optionally a wetting aid.
    22. A printing forme that is imaged by laser-induced transfer with a composition according to Claim 21.
    23. Printing forme according to Claim 22 that is manufactured from plasma-sprayed or flame-sprayed ceramics and/or metal surfaces, such as chromium, brass (Cu52-65% Zn48-35%, e.g. Boltomet L® Cu63Zn37) and/or special steels in the sense of high-alloy steels (according to DIN 17440: 1.43xx (xx = 01, 10, ...) 1.4568, 1.44xx (xx = 04, 35, 01 ...)).
    EP00116753A 1999-08-07 2000-08-03 Thermal transfer sheet for laser-induced marking of a lithographic printing cylinder Expired - Lifetime EP1075963B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE19937478A DE19937478B4 (en) 1999-08-07 1999-08-07 Thermal transfer film for laser-induced coating of a metal surface
    DE19937478 1999-08-07

    Publications (3)

    Publication Number Publication Date
    EP1075963A2 EP1075963A2 (en) 2001-02-14
    EP1075963A3 EP1075963A3 (en) 2001-05-16
    EP1075963B1 true EP1075963B1 (en) 2004-05-26

    Family

    ID=7917681

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP00116753A Expired - Lifetime EP1075963B1 (en) 1999-08-07 2000-08-03 Thermal transfer sheet for laser-induced marking of a lithographic printing cylinder

    Country Status (5)

    Country Link
    US (1) US6677010B1 (en)
    EP (1) EP1075963B1 (en)
    JP (1) JP2001096920A (en)
    CA (1) CA2315536C (en)
    DE (2) DE19937478B4 (en)

    Cited By (1)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US8691915B2 (en) 2012-04-23 2014-04-08 Sabic Innovative Plastics Ip B.V. Copolymers and polymer blends having improved refractive indices

    Families Citing this family (10)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE10045774C2 (en) 2000-09-15 2002-08-14 Roland Man Druckmasch Thermal transfer film with reactive polymer mass for laser-induced coating, its production and use
    DE10063819B4 (en) * 2000-12-21 2006-02-02 Man Roland Druckmaschinen Ag Mask production for the production of a printing form
    NL1017752C2 (en) * 2001-03-30 2002-10-01 Dsm Nv Method for making a plastic molded part with a decorated surface.
    JP2002370465A (en) * 2001-06-14 2002-12-24 Konica Corp Printing plate material, method for forming image on printing plate material and method for printing
    DE102005046863A1 (en) * 2005-09-30 2007-06-14 Man Roland Druckmaschinen Ag printing form
    DE102007007183A1 (en) * 2007-02-14 2008-08-21 Man Roland Druckmaschinen Ag Process for the production of printing plates
    DE102008025583A1 (en) 2008-01-11 2009-07-16 Tesa Ag Pigment layer and method for permanent labeling of a substrate by means of high-energy radiation
    PL2078614T3 (en) 2008-01-11 2014-10-31 Tesa Se Pigment layer and method for long-term inscription of a substrate with high-energy radiation
    CN102516822B (en) * 2011-11-04 2014-08-06 昆明理工大学 Surface-functionalized Fe3O4 nanoparticles as well as preparation method and application thereof
    KR20200106507A (en) * 2017-12-28 2020-09-14 인스티튜트 오브 커뮤니케이션 앤드 컴퓨터 시스템스 (아이씨씨에스)- 내셔널 테크니컬 유니버시티 오브 아테네 (엔티유에이) Dual beam laser transmission

    Family Cites Families (9)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE3941303C1 (en) * 1989-12-14 1990-12-13 Man Roland Druckmaschinen Ag, 6050 Offenbach, De
    GB9215003D0 (en) * 1992-07-15 1992-08-26 Courtaulds Plc Coloured film
    JPH07256907A (en) * 1994-03-25 1995-10-09 Fuji Photo Film Co Ltd Color image forming device
    EP0689940B1 (en) 1994-06-30 1997-09-10 E.I. Du Pont De Nemours And Company Donor element for laser-induced thermal transfer
    DE4430555C1 (en) * 1994-08-27 1996-04-04 Roland Man Druckmasch Method and device for producing a printing form
    US5691103A (en) * 1995-02-17 1997-11-25 Konica Corporation Image forming material, method of preparing the same and image forming method employing the same
    WO1997000295A1 (en) 1995-06-14 1997-01-03 Nippon Shokubai Co., Ltd. Carbon black graft polymer, process for the production of the polymer and use thereof
    US5698363A (en) 1995-07-10 1997-12-16 Konica Corporation Image forming method
    US5691098A (en) * 1996-04-03 1997-11-25 Minnesota Mining And Manufacturing Company Laser-Induced mass transfer imaging materials utilizing diazo compounds

    Cited By (1)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US8691915B2 (en) 2012-04-23 2014-04-08 Sabic Innovative Plastics Ip B.V. Copolymers and polymer blends having improved refractive indices

    Also Published As

    Publication number Publication date
    DE50006568D1 (en) 2004-07-01
    EP1075963A2 (en) 2001-02-14
    DE19937478B4 (en) 2004-08-19
    DE19937478A1 (en) 2001-02-15
    JP2001096920A (en) 2001-04-10
    CA2315536C (en) 2005-06-28
    CA2315536A1 (en) 2001-02-07
    US6677010B1 (en) 2004-01-13
    EP1075963A3 (en) 2001-05-16

    Similar Documents

    Publication Publication Date Title
    DE69935934T2 (en) Positive working thermal imaging element and positive working lithographic printing plate precursor
    DE60024190T2 (en) Infrared laser imageable planographic printing plate and method for its production
    DE69722396T2 (en) THERMAL TRANSFER ELEMENT ADDRESSABLE WITH A LASER FOR IMAGE RECORDING WITH AN INTERLAYER
    DE69812871T2 (en) Heat-sensitive recording element and method for producing planographic printing plates therewith
    DE69839284T2 (en) patterning
    DE69912921T2 (en) LITHOGRAPHIC PRINTING PLATES FOR USE IN A LASER IMAGING DEVICE
    DE60315692T2 (en) METHOD FOR THE PRODUCTION OF A LITHOGRAPHIC PRINTING PLATFORM PROCESSOR
    EP1075963B1 (en) Thermal transfer sheet for laser-induced marking of a lithographic printing cylinder
    DE60218005T2 (en) A radiation-sensitive product, a process for making a radiation-sensitive product and methods of printing or forming an image with the product
    EP1188560B1 (en) Thermal transfer foil with reactive polymer composition for laser-induced imaging, composition,process for producing the foil and printing plate
    DE602004007007T2 (en) Thermally reactive near infrared absorbing polymers and their use in heat sensitive lithographic printing plates
    DE60316826T2 (en) METHOD FOR THE PRODUCTION OF A LITHOGRAPHIC PRINTING PLATFORM PROCESSOR
    DE60318600T2 (en) METHOD FOR PRODUCING A LITHOGRAPHIC PRESSURE PLATE
    DE2543820C2 (en) Process for the production of planographic printing forms by means of laser beams
    DE3246037A1 (en) LIGHT SENSITIVE MIXTURE, LIGHT SENSITIVE COPY MATERIAL MADE THEREOF, AND METHOD FOR PRODUCING A PRINT FORM FROM THE COPY MATERIAL
    EP0913730A1 (en) Process for making a printing form
    DE602004008224T2 (en) THERMAL SENSITIVE LITHOGRAPHIC PRESSURE PLATE ROLLER
    DE60008306T2 (en) Planographic printing plate precursor containing metal compounds and methods of making planographic printing plates
    EP0900653B1 (en) Thermal imageable recording material comprising a layer of a positive working IR sensitive mixture and method of producing lithographic printing plate for offset printing
    DE60021459T2 (en) Planographic printing plate and imaging process
    DE69909711T2 (en) Lithographic printing plate precursor and lithographic process
    DE69908725T2 (en) Imaging element with heat sensitive thiosulfate polymer and method of using same
    DE19850181C2 (en) Radiation-sensitive composition and its use for thermally imageable printing plates
    DE60127684T2 (en) Lithographic printing form, preparation method and use thereof
    DE2231815C2 (en) Method for producing a relief by means of electron beams

    Legal Events

    Date Code Title Description
    PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

    Free format text: ORIGINAL CODE: 0009012

    AK Designated contracting states

    Kind code of ref document: A2

    Designated state(s): CH DE FR GB IT LI NL

    AX Request for extension of the european patent

    Free format text: AL;LT;LV;MK;RO;SI

    PUAL Search report despatched

    Free format text: ORIGINAL CODE: 0009013

    AK Designated contracting states

    Kind code of ref document: A3

    Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

    AX Request for extension of the european patent

    Free format text: AL;LT;LV;MK;RO;SI

    17P Request for examination filed

    Effective date: 20011113

    AKX Designation fees paid

    Free format text: CH DE FR GB IT LI NL

    17Q First examination report despatched

    Effective date: 20030611

    GRAP Despatch of communication of intention to grant a patent

    Free format text: ORIGINAL CODE: EPIDOSNIGR1

    GRAS Grant fee paid

    Free format text: ORIGINAL CODE: EPIDOSNIGR3

    GRAA (expected) grant

    Free format text: ORIGINAL CODE: 0009210

    AK Designated contracting states

    Kind code of ref document: B1

    Designated state(s): CH DE FR GB IT LI NL

    REG Reference to a national code

    Ref country code: GB

    Ref legal event code: FG4D

    Free format text: NOT ENGLISH

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: NV

    Representative=s name: E. BLUM & CO. PATENTANWAELTE

    Ref country code: CH

    Ref legal event code: EP

    REF Corresponds to:

    Ref document number: 50006568

    Country of ref document: DE

    Date of ref document: 20040701

    Kind code of ref document: P

    GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

    Effective date: 20040906

    ET Fr: translation filed
    PLBE No opposition filed within time limit

    Free format text: ORIGINAL CODE: 0009261

    STAA Information on the status of an ep patent application or granted ep patent

    Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

    26N No opposition filed

    Effective date: 20050301

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: PFA

    Owner name: MAN ROLAND DRUCKMASCHINEN AG

    Free format text: MAN ROLAND DRUCKMASCHINEN AG#POSTFACH 10 12 64#63012 OFFENBACH (DE) -TRANSFER TO- MAN ROLAND DRUCKMASCHINEN AG#POSTFACH 10 12 64#63012 OFFENBACH (DE)

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: PFA

    Owner name: MANROLAND AG

    Free format text: MAN ROLAND DRUCKMASCHINEN AG#POSTFACH 10 12 64#63012 OFFENBACH (DE) -TRANSFER TO- MANROLAND AG#MUEHLHEIMER STRA?E 341#63075 OFFENBACH (DE)

    NLT1 Nl: modifications of names registered in virtue of documents presented to the patent office pursuant to art. 16 a, paragraph 1

    Owner name: MANROLAND AG

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: CH

    Payment date: 20080814

    Year of fee payment: 9

    Ref country code: NL

    Payment date: 20080813

    Year of fee payment: 9

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: IT

    Payment date: 20080823

    Year of fee payment: 9

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: GB

    Payment date: 20080821

    Year of fee payment: 9

    REG Reference to a national code

    Ref country code: FR

    Ref legal event code: CD

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: PL

    Ref country code: NL

    Ref legal event code: V1

    Effective date: 20100301

    GBPC Gb: european patent ceased through non-payment of renewal fee

    Effective date: 20090803

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: CH

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090831

    Ref country code: LI

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090831

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: NL

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20100301

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: GB

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090803

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: FR

    Payment date: 20100901

    Year of fee payment: 11

    Ref country code: DE

    Payment date: 20100823

    Year of fee payment: 11

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: IT

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090803

    REG Reference to a national code

    Ref country code: FR

    Ref legal event code: ST

    Effective date: 20120430

    REG Reference to a national code

    Ref country code: DE

    Ref legal event code: R119

    Ref document number: 50006568

    Country of ref document: DE

    Effective date: 20120301

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: FR

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20110831

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: DE

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20120301