DE102015002371B4 - Laser-writable polymer film - Google Patents

Abstract

Single-layer or multi-layer film with at least one laser-active layer of a polymeric material, characterized in that the material of the laser-active layer comprises 35 to 80% by weight of polyester; 10 to 65% by weight of a polymer having a charring index (Char Forming Tendency) of greater than 1.9 and 0.5 to 20 wt .-% of a Verkohlungsadditivs - 0 to 1 wt .-% transesterification catalyst, - 0.005 to 10 wt .-% of an infrared absorber for wavelengths greater than 780 nm; and- 1 to 20 wt .-% of further additives selected from color pigments, thermal stabilizers, polymeric modifiers, process excipients and mixtures thereof, wherein the weight fractions are based on the total weight of the polymer material of the laser-active layer and in total 100 wt. % and the charring additive is selected from aluminum phosphinate Al (HPO), aluminum isobutylphosphinate (CH) CH-Al (HPO), tris (2-hydroxyethyl) -1,3,5-triazinetrione, organic halogen-free oxyimides containing at least one structural element of formula IIIa or Mixtures of the above compounds.

Description

The present invention relates to a mono- or multilayer film having at least one laser-active layer of a polymeric material.

Laser-writable polymeric moldings and films are known in the art. The patent application DE 10 2006 062 269 A1 discloses a laser-markable or laser-weldable film of a polymeric thermoplastic, thermoset, elastomer or rubber containing as additive spherical metal particles with a volume-averaged particle size distribution with a D ₉₉ value of <110 .mu.m, a D ₉₀ value of <75 .mu.m and a D ₅₀ value of <45 microns contains. The metal particles contain metals selected from aluminum, copper, silver, gold, zinc, tin, iron, titanium, vanadium, magnesium and alloys thereof.

JP 2013-001090 A describes a layer material having at least three coextruded layers, wherein a core layer between two outer layers is arranged, at least one of the outer layers or the core layer consists of a blend of an amorphous aromatic polyester and polycarbonate and contains an absorber additive for laser light.

DE 10 2006 045 495 A1 discloses an at least two-layered coextruded film of a polyethylene terephthalate or polyethylene-2,6-naphthalate-based copolymer having a base layer containing a carbonizing polymer-coated laser absorber and a white pigment.

WO 1999/19408 A1 relates to a black colored polymer blend of polycarbonate and polyester which comprises a carbon black as well as a metal salt of a fatty acid-containing pigment and enables the production of articles which are efficiently inscribable by means of laser radiation.

US 2006/0251869 A1 discloses a multilayer document comprising an ink printed core layer, two buffer layers of transparent amorphous polyester, further layers of transparent material, at least one of the further layers comprising a laser writable layer which heats when laser printed and the buffer layers are sufficiently thick to preserve the printed image of the core layer from thermal damage.

Laser-writable films are made of compositions containing as essential component a polymer or a polymer blend as well as various additives and a light absorber. The additives improve the processability of the polymeric composition and impart beneficial mechanical and thermal properties to the film. The films are laser light in the infrared range, ie labeled with a wavelength in the range of 780 nm to 10.6 microns (CO ₂ laser). The laser marking systems most commonly used in the art are based on an Nd-YAG laser which emits laser light having a wavelength of 1064 nm. The light absorbers used in laser-writable films are preferably weakly absorbing or highly transparent in the range of visible light with wavelengths from 380 to 780 nm and have little effect on the visual appearance of the film by coloration or haze. In contrast, the light absorbers have a high absorption compared to the visible wavelength range at the wavelength emitted by the laser marking system. The light emitted by the laser marking system is absorbed by the light absorber in the irradiated areas of the film, whereby a part of the electromagnetic radiation energy is converted into thermal energy and the film is strongly heated. As a result of the intense heating, the polymeric material in the irradiated areas of the film is decomposed and partially pyrolyzed or blackened and blackened. The image generated by the laser marking system in the film, such as a character or a photo, is composed of the thus blackened film areas.

Polycarbonate has a high degree of blackening on laser-induced heating and is very well suited for laser marking. In contrast, polyester is blackened in the inscription with industrial laser marking systems only to a small extent, so that the contrast of the image produced is insufficient. Laser-writable films used in the prior art therefore often contain polycarbonate as an essential component.

Polyester has many advantages over polycarbonate, including greater flexibility, less tendency to break, better scratch resistance, lower lamination temperatures and significantly higher resistance to various chemicals. Therefore, polyester represents a preferred material for many applications, such as personal and security badges, credit cards and packaging. Nonetheless, as a rule, polyester as a material for laser-writable cards and packaging is eliminated because the contrast achievable with industry-standard laser marking systems is inadequate.

Accordingly, the object of the present invention is to provide a polyester-type or polyester-based film which has a high contrast in labeling with laser marking systems common in the art. Here, by the term "polyester-like" is meant a polyester-containing film which has practically the same properties as a polyester-based film.

• - 35 bis 80 Gew.-% Polyester;
• - 10 bis 65 Gew.-% eines Polymers mit einem Verkohlungsindex (Char Forming Tendency) von größer 1,9 und/oder 0,5 bis 20 Gew.-% eines Verkohlungsadditivs;
• - 0 bis 1 Gew.-% Umesterungskatalysator;
• - 0,005 bis 10 Gew.-% eines Infrarotabsorbers für Wellenlängen von größer 780 nm; und
• - 1 bis 20 Gew.-% weiteren Additiven, gewählt aus Farbpigmenten, thermischen Stabilisatoren, polymeren Modifikatoren, Prozesshilfsstoffen und Mischungen davon;

wobei die Gewichtsanteile auf das Gesamtgewicht des polymeren Werkstoffs der laseraktiven Lage bezogen sind und in Summe 100 Gew.-% betragen und
das Verkohlungsadditiv gewählt ist aus Aluminiumphosphinat Al(H₂PO₂)₃, Aluminiumisobutylphosphinat (CH₃)₂CH-Al(H₂PO₂)₂, Tris(2-hydroxyethyl)-1,3,5-triazintrion, organischen halogenfreien Oxyimiden, enthaltend mindestens ein Strukturelement der Formel IIIa

oder Mischungen der vorstehenden Verbindungen.This object is achieved by a single or multilayer film having at least one laser-active layer of a polymeric material consisting of

• - 35 to 80 wt .-% polyester;
• From 10% to 65% by weight of a polymer having a Char Forming Tendency of greater than 1.9 and / or from 0.5 to 20% by weight of a char additive;
• 0 to 1% by weight of transesterification catalyst;
• 0.005 to 10% by weight of an infrared absorber for wavelengths greater than 780 nm; and
• From 1 to 20% by weight of further additives selected from color pigments, thermal stabilizers, polymeric modifiers, process aids and mixtures thereof;

wherein the weight fractions are based on the total weight of the polymer material of the laser-active layer and in total amount to 100 wt .-%, and
the char additive is selected from aluminum phosphinate Al (H ₂ PO ₂ ) ₃ , aluminum isobutylphosphinate (CH ₃ ) ₂ CH-Al (H ₂ PO ₂ ) ₂ , tris (2-hydroxyethyl) -1,3,5-triazinetrione, organic halogen-free oxyimides containing at least one structural element of the formula IIIa

or mixtures of the above compounds.

• - das Polymer mit einem Verkohlungsindex von größer 1,9 gewählt ist aus Polycarbonat, Polyimid, Polyetheretherketon, Polyethylennaphthalat oder einer Mischung der vorstehenden Polymere;
• - der Umesterungskatalysator gewählt ist aus Calciumacetat, Magnesiumacetat, Zinkacetat, Titantetrabutanolat, Lanthan(III)-acetylacetonat, Kobalt(II)-acetylacetonat, Bleiacetat, Hydraten der vorstehenden Verbindungen und Mischungen der vorstehenden Verbindungen und deren Hydraten;
• - der Infrarotabsorber gewählt ist aus
  • - mikro- oder nanoskaligem Rußpigment (Carbon black);
  • - Metalloxiden, Nickeloxid, Zinnoxid, Antimon-dotiertem Zinnoxid (SnO₂:Sb), Titanoxid, Indiumzinnoxid (ITO), Antimonoxid (Sb₂O₃) und Mischungen davon, wobei das Metalloxid vorzugsweise nanoskalig ist und/oder auf einem mikro- oder nanoskaligen mineralischen Träger, insbesondere mikro- oder nanoskaligem Bentonit oder Glimmer fixiert und/oder in mikroskaligen Partikeln aus einem polymeren Werkstoff dispergiert ist;
  • - Aluminium-haltigem Pigment mit einem metallischen Kern mit einem Anteil an elementarem Aluminium von größer oder gleich 50 Gew.-%, bezogen auf das Gewicht des metallischen Kerns, wobei die Aluminium-haltigen Pigmentpartikel einen medianen Durchmesser d₅₀ zwischen 0,5 und 25 µm aufweisen;
  • - organischen Polymethin-Farbstoffen, insbesondere organischen Cyanin-Farbstoffen mit der allgemeinen Strukturformel (R¹N)-[CH=CH]_nCH=(N⁺R¹) ↔ (R¹N⁺)=CH[CH=CH]_n-(NR¹) mit 2 ≤ n ≤ 5 , worin (R¹N) und (N⁺R¹) eine Stickstoff-haltige heterozyklische Gruppe, wie Imidazol, Pyridin, Pyrrol, Chinon oder Thiazol repräsentieren und die Polyenkette CH[CH=CH]_n zur Stabilisierung gegebenfalls ein aromatisches Ringsystem enthält;
  • - Metallphosphaten, Kupfer(II)-hydroxid-phosphat, ;
  • - Phthalocyanin-, Dithiolan- oder Oxathiolan-Komplexen der Metalle Co, Cr, Cu, Fe, Ni, Pt oder Vandiumoxid (VO);
  • - Naphthachinonen und Anthrachinonen, die Benzothiazol-Gruppen enthalten;
  • - Squarylium-Farbstoffen, insbesondere Verbindungen mit der Strukturformel Va
  
  worin R² ein aromatisches Ringsystem und (NR³) bzw. (N⁺R³) Stickstoff-haltige Gruppen repräsentieren;
• - Croconium-Farbstoffen, insbesondere Verbindungen mit der Strukturformel VIa oder VIb
  
  worin R⁴ ein aromatisches Ringsystem und (NR⁵) bzw. (N⁺R⁵) Stickstoff-haltige Gruppen repräsentieren;
• - Triphenylmethan-Farbstoffen, insbesondere Verbindungen mit der Strukturformel VIIa oder VIIb
  
• - Salzen des Iminium-Kations, insbesondere einer Verbindung mit der Strukturformel VIIIa
  
  worin X^- ein Anion bezeichnet, wie ClO₄ (Perchlorat) oder SbF₆ (Antimonhexafluorid);
• - Salzen des Diiminium-Kations, insbesondere Verbindungen mit der Strukturformel VIIIc (= N,N,N',N'-tetrakis(4-dibutylaminophenyl)-p-phenylen-diiminium 2X)
  
  worin X^- ein Anion bezeichnet, wie ClO₄ ^- (Perchlorat) oder SbF₆ ^- (Antimonhexafluorid);
• - Poly-3,4-ethylendioxythiophen (PEDOT), insbesondere einer Verbindung aus Poly-3,4-ethylendioxythiophen und Polystyrolsulfonsäure; oder Mischungen der vorstehenden Stoffe;
• - der Polyester der laseraktiven Lage ein amorpher Polyester ist;
• - der Polyester der laseraktiven Lage glykol- oder säuremodifiziertes Polyethylenterephthalat ist;
• - der Polyester der laseraktiven Lage PETG oder APET ist;
• - der Polyester der laseraktiven Lage eine Kristallisationshalbwertszeit von größer 5 min, größer 20 min, größer 60 min oder größer 120 min aufweist;
• - die laseraktive Lage eine Dicke von 20 bis 200 µm, 20 bis 150 µm oder 30 bis 100 µm hat;
• - die Folie eine Trägerlage aus einem polymeren Werkstoff umfasst und die laseraktive Lage mit der Trägerfolie durch Lamination verbunden ist;
• - der polymere Werkstoff der Trägerlage zu 40 bis 90 Gew.-% aus Polyester besteht, bezogen auf das Gesamtgewicht des polymeren Werkstoffs der Trägerlage;
• - der polymere Werkstoff der Trägerlage 1 bis 20 Gew.-% Farbpigment enthält, bezogen auf das Gesamtgewicht des polymeren Werkstoffs der Trägerlage;
• - die Folie eine zwischen der Trägerlage und der laseraktiven Lage angeordnete Farblage aus einem polymeren Werkstoff umfasst und die Farblage mit der Trägerlage und der laseraktiven Lage laminiert ist;
• - der polymere Werkstoff der Farblage 40 bis 90 Gew.-% Polyester und 1 bis 20 Gew.-% Farbpigmente enthält, wobei die Gewichtsanteile auf das Gesamtgewicht des polymeren Werkstoffs der Farblage bezogen sind;
• - die Folie eine Decklage aus einem polymeren Werkstoff umfasst und die Deckfolie mit der laseraktiven Lage durch Lamination verbunden ist; und/oder
• - der polymere Werkstoff der Decklage zu 40 bis 95 Gew.-% aus Polyester besteht, bezogen auf das Gesamtgewicht des polymeren Werkstoffs der Decklage.

Advantageous embodiments of the film are characterized in that:

• the polymer having a char index of greater than 1.9 is selected from polycarbonate, polyimide, polyetheretherketone, polyethylene naphthalate or a mixture of the above polymers;
• - The transesterification catalyst is selected from calcium acetate, magnesium acetate, zinc acetate, titanium tetrabutoxide, lanthanum (III) acetylacetonate, cobalt (II) acetylacetonate, lead acetate, hydrates of the above compounds and mixtures of the above compounds and their hydrates;
• - the infrared absorber is selected
  • - micro- or nanoscale carbon black pigment (carbon black);
  • - Metalloxiden, nickel oxide, tin oxide, antimony-doped tin oxide (SnO ₂ : Sb), titanium oxide, indium tin oxide (ITO), antimony oxide (Sb ₂ O ₃ ) and mixtures thereof, wherein the metal oxide is preferably nanoscale and / or on a micro- or nanoscale mineral carrier, in particular micro- or nanoscale bentonite or mica fixed and / or dispersed in micro-scale particles of a polymeric material;
  • Aluminum-containing pigment having a metallic core with a content of elemental aluminum greater than or equal to 50 wt .-%, based on the weight of the metallic core, wherein the aluminum-containing pigment particles have a median diameter d ₅₀ between 0.5 and 25 have μm;
  • - organic polymethine dyes, in particular organic cyanine dyes having the general structural formula (R ¹ N) - [CH = CH] _n CH = (N ⁺ R ¹ ) ↔ (R ¹ N ⁺ ) = CH [CH = CH] _n - (NR ¹ ) where 2 ≤ n ≤ 5, wherein (R ¹ N) and (N ⁺ R ¹ ) represent a nitrogen-containing heterocyclic group such as imidazole, pyridine, pyrrole, quinone or thiazole and the polyene chain CH [CH = CH] _n for stabilization optionally contains an aromatic ring system;
  • - metal phosphates, copper (II) hydroxide phosphate,;
  • Phthalocyanine, dithiolane or oxathiolane complexes of the metals Co, Cr, Cu, Fe, Ni, Pt or vandium oxide (VO);
  • - Naphthaquinones and anthraquinones containing benzothiazole groups;
  • - Squarylium dyes, in particular compounds having the structural formula Va
  
  wherein R ^{2 represents} an aromatic ring system and (NR ³ ) or (N ⁺ R ³ ) nitrogen-containing groups;
• Croconium dyes, in particular compounds having the structural formula VIa or VIb
  
  wherein R ^{4 represents} an aromatic ring system and (NR ⁵ ) or (N ⁺ R ⁵ ) nitrogen-containing groups;
• - Triphenylmethane dyes, in particular compounds having the structural formula VIIa or VIIb
  
• Salts of the iminium cation, in particular a compound having the structural formula VIIIa
  
  wherein X ^- represents an anion such as ClO ₄ (perchlorate) or SbF ₆ (antimony hexafluoride);
• Salts of the diimine cation, in particular compounds of the structural formula VIIIc (= N, N, N ', N'-tetrakis (4-dibutylaminophenyl) -p-phenylene-diiminium 2X)
  
  wherein X ^- represents an anion such as ClO ₄ ^- (perchlorate) or SbF ₆ ^- (antimony hexafluoride);
• - Poly-3,4-ethylenedioxythiophene (PEDOT), in particular a compound of poly-3,4-ethylenedioxythiophene and polystyrene sulfonic acid; or mixtures of the above substances;
• the polyester of the laser active layer is an amorphous polyester;
• the polyester of the laser-active layer is glycolic or acid-modified polyethylene terephthalate;
• the polyester of the laser active layer is PETG or APET;
• the polyester of the laser-active layer has a crystallization half-life of greater than 5 minutes, greater than 20 minutes, greater than 60 minutes or greater than 120 minutes;
• - The laser-active layer has a thickness of 20 to 200 microns, 20 to 150 microns or 30 to 100 microns;
• - the film comprises a carrier layer of a polymeric material and the laser-active layer is bonded to the carrier film by lamination;
• - The polymeric material of the carrier layer to 40 to 90 wt .-% of polyester, based on the total weight of the polymeric material of the carrier layer;
• the polymeric material of the carrier layer contains from 1 to 20% by weight of colored pigment, based on the total weight of the polymeric material of the carrier layer;
• - The film comprises a disposed between the carrier layer and the laser-active layer color layer of a polymeric material and the color layer is laminated with the carrier layer and the laser-active layer;
• - The polymeric material of the color layer contains 40 to 90 wt .-% polyester and 1 to 20 wt .-% of colored pigments, wherein the weight fractions are based on the total weight of the polymeric material of the color layer;
• - The film comprises a cover layer of a polymeric material and the cover sheet is connected to the laser-active layer by lamination; and or
• - The polymeric material of the cover layer to 40 to 95 wt .-% of polyester, based on the total weight of the polymeric material of the cover layer.

According to the invention, the term "infrared absorber for wavelengths greater than 780 nm" denotes dyes or micro- or nanoscale pigments which have an integral absorption at wavelengths greater than 780 nm, which is greater by a factor of at least 1.5 than the integral absorption in the wavelength range from 380 to 780 nm, where by integral absorption is meant the absorption integrated over the wavelength.

In the context of the present invention, the term "microscale" denotes a material which is present as a free-flowing powder or in the form of particles or agglomerates dispersed in a matrix, the powder grains or dispersed particles or agglomerates having a dimension of less than 5 μm in at least one dimension ,

Analogously, the term "nanoscale" denotes a material which is present as a free-flowing powder or in the form of particles or agglomerates dispersed in a matrix, wherein the powder grains or dispersed particles or agglomerates have a dimension of less than 500 nm, in particular of at least one dimension less than 200 nm.

The dimensions of micro- or nanoscale particles or agglomerates are determined according to the invention by means of a scanning electron microscope or a transmission electron microscope and image analysis software such as ImageJ (http://imagej.nih.gov/ij). In this case, at least 100, preferably at least 1000 particles or agglomerates are digitally measured with the aid of the image analysis software on the basis of digitized electron micrographs. Due to the high lateral resolution of prior art electron microscopes ranging from a few angstroms to 10 nm depending on the setting of the electron optics and the beam parameters, the equivalent diameter of the particles or agglomerates can be determined with high reliability.

Alternatively or concomitantly, the dimensions of micro- or nanoscale particles or agglomerates are measured by means of light scattering or photon correlation spectroscopy. A suitable measuring instrument for particle sizes from 0.3 nm to 8 μm is used, inter alia, by Horiba Ltd. (Kyoto, Japan) under the product name nano partica SZ-100 commercially offered.

According to the invention, the term "median diameter d ₅₀ " denotes a particle ensemble in which 50% by volume of the particles have a volume-equivalent spherical diameter of less than or equal to d ₅₀ and 50% by volume of the particles have a volume-equivalent spherical diameter of greater than or equal to d ₅₀ . By volume equivalent ball diameter is meant, depending on the measuring method used, the diameter of a sphere which has the same surface area, the same projection area or the same light scattering (diffraction disc) as the particle under investigation.

The laser writable film of the invention is prepared by methods known in the art such as extrusion, co-extrusion, simple calendering or calendering in conjunction with lamination. Suitable film extruder and Folienkalanderanlagen suitable for this purpose and the associated components are offered commercially by various companies.

polyester

The laser-active layer according to the invention is made of a material which is from 35 to 95% by weight, from 40 to 95% by weight, from 45 to 95% by weight, from 50 to 95% by weight, from 55 to 95% by weight 95% by weight, to 60 to 95% by weight or to 50 to 80% by weight of polyester.

The polyester used for the laser-active layer in particular amorphous glycol-modified polyethylene terephthalate (PETG), amorphous acid-modified polyethylene terephthalate or APET. Preferably, in the amorphous glycol modified polyethylene terephthalate (PETG), glycol units are replaced by 1,4-cyclohexanedimethanol units. Such modified with 1,4-cyclohexanedimethanol, polyethylene terephthalate is commercially available from Eastman Chemical Company ^® (Tennessee, USA) under the product Eastar copolyester ^® 6,763th

In another expedient embodiment of the invention, a semi-crystalline or amorphous copolyester having a crystallization half-life of at least 5 minutes is used in the laser-active layer. Such a copolyester is for example in the patent EP 1 066 339 B1 of ^Eastman® Chemical Company. This copolyester is composed of (i) diacid residue components and (ii) diol residue components. The diacid residue components (i) comprise at least 80 mol% of a diacid residue component selected from terephthalic acid, naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid and mixtures thereof, based on all diacid residue components contained in the copolyester (= 100 mol%). The diol residue components (ii) comprise from 80 to 100 mole percent of a diol residue component selected from diols having from 2 to 10 carbon atoms and mixtures thereof and from 0 to 20 mole percent of a modifying diol selected from 1,3-propanediol, 1,4-butanediol , 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, propylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol , based on all diol residues contained in the copolyester (= 100 mol%). Amorphous or semi-crystalline copolyesters having a crystallization half-life of at least 5 minutes are well suited to conventional extrusion and calendering processes. With a polymeric material containing a substantial proportion - usually more than 50 wt .-% - semi-crystalline or amorphous copolyester having a crystallization half-life of at least 5 minutes, homogeneous and virtually defect-free films can be produced by calendering.

Amorphous or semi-crystalline copolyesters having a crystallization half-life of at least 5 minutes are commercially available from, among others, ^Eastman® Chemical Company under the product name ^Cadence® Copolyester. These copolyesters are used as the main component for the production of polyester films, their proportion of the total weight of the polyester film is usually more than 40 to 70 wt .-%, is.

The crystallization half-life of the polyester or copolyester used for the laser-active layer is determined by means of a differential scanning calorimeter (DSC). Differential Scanning Calorimetry (DSC) is a standard method for the measurement of thermal properties, in particular the phase transition temperatures of solids. In the present invention, the crystallization half-life is determined by heating 15 mg of the copolyester to be measured to 290 ° C, then subsequently cooled in the presence of helium at a rate of 320 ° C per minute to a predetermined temperature of 180 to 210 ° C and the Time period until reaching the isothermal crystallization temperature or the crystallization peak of the DSC curve detected. Based on the time-dependent course of the crystallization, the crystallization half-life is determined. The crystallization half-life corresponds to the time required at the predetermined temperature of 180 to 210 ° C after the initial phase of crystallization to obtain in the sample 50% of the maximum achievable crystallinity.

Polymer with a char index of greater than 1.9

According to the invention, the proportion of the polymer having a Char Forming Tendency of greater than 1.9 in the laser-writable layer is 10 to 65 wt .-%, 10 to 55 wt .-%, 10 to 45 wt .-%, 10 to 35 Wt .-%, 20 to 50 wt .-% or 20 to 40 wt .-%.

ermittelt, worin CR den nach Erhitzung des Polymers auf 900 °C erhaltenen Kohlerückstand in Prozent, bezogen auf das Gewicht M des ursprünglichen Polymers, N_i die Anzahl der Struktureinheiten des Typs i im Polymer und C_FTi die Zahl der Kohlenstoffäquivalente der Struktureinheit des Typs i bezeichnet. Die Berechnung von C_FT gemäß der vorstehenden Beziehung ist nur für halogenfreie Polymere anwendbar und wurde von van Krevelen eingeführt in Verbindung mit tabellierten Werten C_FTi von sämtlichen, für halogenfreie Polymere relevanten Struktureinheiten i (D. W. van Krevelen, Polymer 1975, 16, 615). Anhand der Ergebnisse von Pyrolysemessungen an etwa 100 Polymeren wurde von van Krevelen gezeigt, dass die mittlere Abweichung zwischen dem experimentell bestimmten und dem berechneten C_FT-Wert lediglich 3,5 % beträgt.The Verkohlungsindex (Char Forming Tendency or C _FT) of a polymer is calculated from the relationship $$C_{FT}=M\left(\begin{array}{cc}\frac{\mathrm{<figure-callout\; id="12"\; label="C\; R"\; filenames="DE102015002371B4\_0089.png"\; state="\{\{state\}\}">C\; </figure-callout>}R}{12}& \frac{1}{100}\end{array}\right)={\displaystyle \underset{i}{\Sigma }{N}_i{C}_{FTi}}$$

where CR is the carbon residue obtained after heating the polymer at 900 ° C in percent, based on the weight M of the original polymer, N _{i is} the number of structural _units of type i in the polymer and C is _FTi the number of carbon _{equivalents of} the structural unit of type i designated. The calculation of C _FT according to the above relationship is applicable only to halogen-free polymers and was introduced by van Krevelen in conjunction with tabulated values C _FTi of all structural _units relevant to halogen-free polymers i (DW van Krevelen, Polymer 1975, 16, 615). Based on the results of pyrolysis measurements on about 100 polymers, van Krevelen showed that the average deviation between the experimentally determined and the calculated C _FT value is only 3.5%.

72 -CHOH- 4

120

12

12

24

36

36

42

48

42

60

84

72

84

96

108

60

132 Tabelle 2: Verkohlungsindizes C_FT ausgewählter Polymere Polymer C_FT Polymer C_FT Polyethylen 0 Polyoxymethylen 0 Cycloolefincopolymer 0 Polyethylenterephthalat 1,25 Polypropylen -1,5 Polymethylmethacrylat -1,5 Polystyrol 1 Polyamid (Nylon 6) 0 Acrylnitril-Butadien-Styrol-Copolymerisat 1 Polyethylennaphthalat 3,25 Polyetheretherketon 12 Polyimid 20 Polycarbonat 5 Polybutylen 0 Below, by way of example, carbon _equivalents C _{FTi of} selected structural _units i and calculated carbonization _indexes C _{FT of} some polymers are indicated. Table 1: _{Charring indices} C _{FTi of} selected structural _units Structural unit i C _FTi Structural unit i C _FTi aliphatic groups (not -CHOH-) 0

72 -CHOH- 4

120

12

12

24

36

36

42

48

42

60

84

72

84

96

108

60

132 Table 2: Charring indices C _{FT of} selected polymers polymer C _FT polymer C _FT polyethylene 0 polyoxymethylene 0 cycloolefin 0 polyethylene terephthalate 1.25 polypropylene -1.5 polymethylmethacrylate -1.5 polystyrene 1 Polyamide (nylon 6) 0 Acrylonitrile-butadiene-styrene copolymer 1 polyethylene 3.25 polyetheretherketone 12 polyimide 20 polycarbonate 5 polybutylene 0

If the laser-active layer according to the invention is produced from a material which contains polyester and another polymer, such as polycarbonate or polyimide, with a char index of greater than 1.9, the material may be a transesterification catalyst to improve the miscibility of these polymers be added. Often contain industrially used polymeric raw materials, such as polyethylene terephthalate, residues of polymerization catalysts, which also act as transesterification catalysts. If so, it is not necessary to use an additional transesterification catalyst to achieve good miscibility of the polymers contained in the material.

Verkohlungsadditive

According to the invention, the charring additive used is tris (2-hydroxyethyl) -1,3,5-triazinetrione (THEIC) having the structural formula I.

vorgesehen.Aluminum phosphinate Al (H ₂ PO ₂ ) ₃ having the structural formula IIa or aluminum isobutylphosphinate (CH ₃ ) ₂ CH-Al (H ₂ PO ₂ ) ₂ having the structural formula IIb,

intended.

Furthermore, in the context of the invention, organic halogen-free oxyimides containing at least one structural element of the formula IIIa are provided as a charring additive

wobei R⁶ und R⁷ unabhängig voneinander für Wasserstoff oder einen Alkyl-, Cycloalkyl-, Aryl-, Heteroaryl- oder Acyl-Rest stehen, der gegebenenfalls substituiert ist.The organic halogen-free oxyimides have in particular one of the structural formulas IIIb to IIIt

wherein R ⁶ and R ⁷ independently represent hydrogen or an alkyl, cycloalkyl, aryl, heteroaryl or acyl radical which is optionally substituted.

infrared absorber

In the context of the present invention, the term "infrared absorber" includes carbon black, organic dyes, metal-organic dyes, complexes and salts of organic or inorganic groups and organic dyes, metals, metal oxides and mixtures of the above substances as well as micro- or nanoscale Pigments and dispersions of micro- or nanoscale pigments in a polymer matrix (masterbatches). The micro- or nano-scale pigments and dispersions of micro- or nanoscale pigments in a polymeric matrix contain as infrared absorbers carbon black, organic dyes, metal-organic dyes, complexes and salts of organic or inorganic groups and organic dyes, metals and / or metal oxides bound on a micro- or nanoscale inorganic support such as bentonite or mica or dispersed in a polymeric material. A polymeric material related to the micro- or nanoscale pigments comprises one, two or three polymers, with a polymer preferably having a char index of greater than 1.9. In an advantageous embodiment, the polymeric material used for the micro- or nanoscale pigments comprises two or three polymers and a compatibilizer, such as maleic anhydride, or a transesterification catalyst, which ensure good miscibility of the polymers. In a further expedient embodiment, a polymeric material for the micro- or nanoscale pigments and dispersions of micro- or nanoscale pigments in a polymeric matrix also contains a charring additive.

The proportion of the infrared absorber in the laser-active layer is 0.005 to 20 wt .-%, 0.01 to 10 wt .-%, 0.01 to 5 wt .-% or 0.01 to 3 wt .-%, based on the Total weight of the material of the laser-active layer.

According to the invention, micro- or nanoscale metal oxides are used as infrared absorbers, in particular oxides of the metal tungsten with the stoichiometric formula WO _3-p , where W denotes tungsten and O denotes oxygen and p denotes an integer greater than or equal to 0.1 and less than or equal to 1 (0.1 ≤ p ≤ 1), and tungsten bronzes having the stoichiometric formula M _r W _s O _3-t , wherein M is one or more groups, atoms or metals selected from NH ₄ , H, Li, Na, K , Rb, Cs, Ca, Ba, Sr, Fe, Sn, Mo, Nb, Ta, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, W, Tungsten, and O Oxygen and r, s, t are real numbers satisfying the following conditions: 1 ≤ r + s ≤ 1.5; 0.001 ≦ r / s ≦ 1 and 0 ≦ t ≦ 1.

Particularly suitable tungsten bronzes are those having a stoichiometric formula selected from H _0.53 WO ₃ , Na _0.33 WO ₃ , K _0.33 WO ₃ , Cs _0.33 WO ₃ , Ba _0.33 WO ₃ , Rb _0.33 WO ₃ .

In accordance with the invention, tungsten oxides having a substoichiometric oxygen content, such as WO _2,7 and tungsten bronzes with a stoichiometric formula H _0.53 WO ₃ , Na _0.33 WO ₃ or Cs _0.33 WO _{3 are} preferred. Among the above tungsten compounds are those having stoichiometric formula Cs _u WO ₃ with 0.2≤u≤0.5 and Na _x Cs _y WO ₃ with 0.08≤x≤0.14 and 0.18≤y≤0.26 , in particular Na _0.11 Cs _0.22 WO ₃ preferred.

The above tungsten oxides such as WO _2,7 are commercially available from various manufacturers in the form of micro- or nanoscale powders with particle sizes of 10 nm to 1 mm, 10 nm to 500 nm and 10 nm to 200 nm. Among other things, such tungsten oxides are produced by reduction of ammonium tungstate in a plasma reactor.

Similarly, the above tungsten bronzes, such as Na _0.11 Cs _0.22 WO _{3 can be produced} by heating, drying and grinding aqueous solutions of ammonium tungstates and metallic salts to temperatures in the range of 300 to 800 ° C (see K. Moon, J. Cho, Y. Lee, PJ Yoo, CW Bark, J. Park, Near Infrared Shielding Properties of Quaternary Tungsten Bronze Nanoparticle Na _0.11 Cs _0.22 WO ₃ , Bull. Korean Chem. Soc. 2013, 34, 3, 731 ).

Suitably, the above tungsten oxides or tungsten bronzes are used in the laser-active layer in a concentration of 0.01 to 3.0 wt .-%, based on the total weight of the polymer material of the laser-active layer.

Cyanine compounds, merocyanine compounds, benzene-ethiol-metal complexes, mercapto-phenol-metal complexes, aromatic di-amine-metal complexes, iminium compounds, di-iminium compounds, amine compounds, nickel-metal complexes, are also used according to the invention as infrared absorbers. Phthalocyanine compounds, anthraquinone compounds, naphthalene-cyanine compounds or metal-naphthalo-cyanine compounds used. If the infrared absorber is a metal-organic compound, the metal used is in particular low-toxic vanadium, aluminum, titanium and, alternatively, silanes.

In particular, the cyanine compounds related to infrared absorbers have the general structural formula (R ¹ N) - [CH =CH] _n CH = (N ⁺ R ¹ ) ↔ (R ¹ N ⁺ ) = CH [CH = CH] _n - (NR ¹ ) with 2 ≤ n ≤ 5, wherein (R ¹ N) and (R ¹ N ⁺ ) represent a nitrogen-containing heterocyclic group such as imidazole, pyridine, pyrrole, quinone or thiazole and the polyene chain CH [CH = CH] _n for stabilization optionally contains an aromatic ring system.

worin X^- ein Anion bezeichnet, wie beispielsweise I^- (Jod) oder ClO₄ ^- (Perchlorat).Cyanine compounds used according to the invention as infrared absorbers have inter alia one of the structural formulas IVa, IVb, Ivc, IVd or IVe

wherein X ^- denotes an anion, such as I ^- (iodine) or ClO ₄ ^- (perchlorate).

wobei wobei R’ und R” unabhängig voneinander für Wasserstoff, einen Alkyl- oder Acyl-Rest und X für O (Sauerstoff), S (Schwefel), Se (Selen) oder Te (Tellur) steht.The squarylium and croconium compounds, which are related as infrared absorbers, have in particular the structural formula Vb, respectively VIc, VId or VIe

wherein R 'and R "independently represent hydrogen, an alkyl or acyl radical and X represents O (oxygen), S (sulfur), Se (selenium) or Te (tellurium).

wobei M ein Metall, wie Nickel, Kobalt oder Platin ist; X Schwefel oder Sauerstoff bezeichnet; R = H, R = CH₃ oder R = OCH₃ und R⁴ eine Alkylgruppe, insbesondere eine tert-Butylgruppe ist.Organometallic compounds used as infrared absorbers are, in particular, those having the structural formula IXa, IXb or IXc

wherein M is a metal such as nickel, cobalt or platinum; X denotes sulfur or oxygen; R = H, R = CH ₃ or R = OCH ₃ and R ^{4 is} an alkyl group, in particular a tert-butyl group.

worin M(II) ein zweiwertiges Metall, wie Kupfer oder Kobalt bezeichnet.Phthalocyanines, metal salts of phthalocyanines and compounds derived therefrom comprising benzene rings, in particular a compound having the structural formula XI, form a further group of infrared absorbers used according to the invention

wherein M (II) denotes a divalent metal such as copper or cobalt.

Quinones, in particular having the structural formula Xa, Xb, Xc or Xd, are also used as infrared absorbers

Another provided in the invention infrared absorber contains poly-3,4-ethylene-dioxythiophene (PEDOT). In particular, a compound of poly-3,4-ethylenedioxy-thiophene and polystyrene sulfonic acid is used, which is commercially available from Bayer AG under the product name Baytron ^® P.

The infrared absorbers preferably used within the scope of the invention absorb electromagnetic radiation having wavelengths in the range from 730 to 2500 nm. Infrared absorbers which have low absorption in the visible wavelength range from 380 to 780 nm and are substantially colorless are particularly preferred. Among others, compounds of the type described below are used as infrared absorbers.

worin X^- ein Anion bezeichnet, wie beispielsweise I^- (Jod). Die vorstehende Verbindung mit der Strukturformel IVf (= 2-[2-[2-chlor-3-[2-(3,3-dimethyl-1-ethyl-1,3-dihydro-benzo[e]indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]-ethenyl] -3,3-dimethyl-1-ethyl-3H-benzo[e]indolium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 815 nm und ist kommerziell erhältlich von American Dye Source Inc., Baie d'Urfé, Quebec, Kanada unter der Produktbezeichnung ADS815EI.A compound having the structural formula IVf

wherein X ^- denotes an anion, such as I ^- (iodine). The above compound having the structural formula IVf (= 2- [2- [2-chloro-3- [2- (3,3-dimethyl-1-ethyl-1,3-dihydro-benzo [e] indol-2-ylidenes ethylidene] -1-cyclohexen-1-yl] -ethenyl] -3,3-dimethyl-1-ethyl-3H-benzo [e] indolium X) has a maximum absorption at a wavelength of 815 nm and as solution in methanol is commercially available from American Dye Source Inc., Baie d'Urfé, Quebec, Canada under the product designation ADS815EI.

A compound having the structural formula IVg

The above compound having the structural formula IVg (= 2- [2- [2-chloro-3 - [(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidenes) ethylidenes] -1 -cyclohexen-1-yl] -ethenyl] -1,3,3-trimethyl-3H-indolium X), wherein X ^{- is} an anion , such as I ^- (iodine) or ClO ₄ ^- (perchlorate), has a maximum absorption at 775 nm wavelength as a solution in methanol and is commercially available from American Dye Source Inc. under the product designation ADS775MI, respectively ADS775MP.

A compound with the structural formula IVh

The above compound having the structural formula IVh (= 2- [2- [2-chloro-3 - [(3,3-dimethyl-1-propyl-1,3-dihydro-2H-indol-2-ylidenes) -ethylidenes] 1-cyclohexen-1-yl] -ethenyl] -3,3-dimethyl-1-propyl-3H-indolium X), wherein X ^- denotes an anion, such as I ^- (iodine) or ClO ₄ ^- (perchlorate) has a maximum absorption at 780 nm wavelength as a solution in methanol and is commercially available from American Dye Source Inc. under the product designation ADS775PI, respectively ADS775PP.

worin X^- ein Anion bezeichnet, wie beispielsweise ClO₄ ^- (Perchlorat). Die vorstehende Verbindung mit der Strukturformel IVi (= 2-[2-[2-chlor-3-[(3,3-dimethyl-1-(2-hydroxyethyl)-1,3 -dihydro-2H-indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(2-hydroxyethyl)-3H-indolium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 780 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS780HO.A compound with the structural formula IVi

wherein X ^- denotes an anion, such as ClO ₄ ^- (perchlorate). The above compound having the structural formula IVi (= 2- [2- [2-chloro-3 - [(3,3-dimethyl-1- (2-hydroxyethyl) -1,3-dihydro-2H-indol-2-ylidenes ) -ethylidene] -1-cyclohexen-1-yl] -ethenyl] -3,3-dimethyl-1- (2-hydroxyethyl) -3H-indolium X) has a maximum absorption at a wavelength of 780 nm as a solution in methanol and is commercially available from American Dye Source Inc. under the product designation ADS780HO.

worin X^- ein Anion bezeichnet, wie beispielsweise Cl^- (Chlor). Die vorstehende Verbindung mit der Strukturformel IVj (= 2-[2-[3-[2-(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidene)-ethylidene]-2-(1-phenyl-1H-tetrazol-5-yl-sulfanyl)-1-cyclohexen-1-yl]-ethenyl]-1,3,3-trimethyl-3H-indolium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 798 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS798SM.A compound having the structural formula IVj

wherein X ^- denotes an anion, such as Cl ^- (chlorine). The above compound having the structural formula IVj (= 2- [2- [3- [2- (1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidenes) -ethylidenes] -2- ( 1-phenyl-1H-tetrazol-5-yl-sulfanyl) -1-cyclohexen-1-yl] -ethenyl] -1,3,3-trimethyl-3H-indolium X) has maximum absorption as a solution in methanol Wavelength of 798 nm and is commercially available from American Dye Source Inc. under the product designation ADS798SM.

worin X^- ein Anion bezeichnet, wie beispielsweise CH₃(C₆H₄)SO₃ ^- (4-methyl-benzolsufonat). Die vorstehende Verbindung mit der Strukturformel IVk (= 2-[2-[2-(4-methyl-benzyloxy)-3-[2-(1,1,3-trimethyl-1,3-dihydro-2H-benzo[e]indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-1,1,3-trimethyl-3H-benzo[e]indolium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 811 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS800AT.A compound with the structural formula IVk

wherein X ^- denotes an anion, such as CH ₃ (C ₆ H ₄ ) SO ₃ ^- (4-methyl-benzenesulfonate). The above compound having the structural formula IVk (= 2- [2- [2- (4-methylbenzyloxy) -3- [2- (1,1,3-trimethyl-1,3-dihydro-2H-benzo [e ] indol-2-ylidenes) -ethylidenes] -1-cyclohexen-1-yl] -ethenyl] -1,1,3-trimethyl-3H-benzo [e] indolium X) has a maximum absorption in methanol as a solution in methanol Wavelength of 811 nm and is commercially available from American Dye Source Inc. under the product designation ADS800AT.

worin X^- ein Anion bezeichnet, wie beispielsweise CH₃(C₆H₄)SO₃ (4-methyl-benzolsufonat). Die vorstehende Verbindung mit der Strukturformel IV1 (= 2-[2-[2-chlor-3-[2-(1,1,3-trimethyl-1,3-dihydro-2H-benzo[e]indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-1,1,3-trimethyl-3H-benzo[e]indolium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 812 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS830AT.A compound with structural formula IVI

wherein X ^- denotes an anion, such as CH ₃ (C ₆ H ₄ ) SO ₃ (4-methyl-benzenesulfonate). The above compound having the structural formula IV1 (= 2- [2- [2-chloro-3- [2- (1,1,3-trimethyl-1,3-dihydro-2H-benzo [e] indol-2-ylidenes ) -ethylidene] -1-cyclohexen-1-yl] -ethenyl] -1,1,3-trimethyl-3H-benzo [e] indolium X) has a maximum absorption at a wavelength of 812 nm as solution in methanol commercially available from American Dye Source Inc. under the product name ADS830AT.

worin Z⁺ ein Kation bezeichnet, wie beispielsweise Na⁺ (Natrium). Die vorstehende Verbindung mit der Strukturformel IVm (= 2-[2-[2-chlor-3-[2-(3,3-dimethyl-1-(4-sulfobutyl)-1,3-dihydro-2H-indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(4-sulfobutyl)-1H-indolium Z) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 782 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS780WS.A compound with the structural formula IVm

wherein Z ⁺ denotes a cation, such as Na ⁺ (sodium). The above compound having the structural formula IVm (= 2- [2- [2-chloro-3- [2- (3,3-dimethyl-1- (4-sulfobutyl) -1,3-dihydro-2H-indole-2 -ylidene) -ethylidene] -1-cyclohexen-1-yl] -ethenyl] -3,3-dimethyl-1- (4-sulfobutyl) -1H-indolium Z) has a maximum absorption at a wavelength of 782 nm and is commercially available from American Dye Source Inc. under the product designation ADS780WS.

worin Z ein Kation bezeichnet, wie beispielsweise HN(CH₃)₃ ⁺ (Triethylammonium). Die vorstehende Verbindung mit der Strukturformel IVn (= 2-[2-[2-chlor-3-[2-(3-(4-sulfobutyl)-3H-benzothiazol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3-(4-sulfobutyl)benzothiazonium Z) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 803 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS795WS.A compound having the structural formula IVn

wherein Z denotes a cation, such as HN (CH ₃ ) ₃ ⁺ (triethylammonium). The above compound having the structural formula IVn (= 2- [2- [2-chloro-3- [2- (3- (4-sulfobutyl) -3H-benzothiazol-2-ylidenes) ethylidenes] -1-cyclohexene-1 -yl] -ethenyl] -3- (4-sulfobutyl) benzothiazonium Z) has a maximum absorption at 803 nm wavelength as a solution in methanol and is commercially available from American Dye Source Inc. under the product designation ADS795WS.

worin Z ein Kation bezeichnet, wie beispielsweise H⁺ (Wasserstoff). Die vorstehende Verbindung mit der Strukturformel IVo (= 2-[2-[2-chlor-3-[2-(3,3-dimethyl-1-(4-sulfobutyl)-1,3-dihydro-2H-benzo[e]indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-benzo[e]indolium Z) hat eine maximale Absorption bei einer Wellenlänge von 819 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS830WS.A compound with the structural formula IVo

wherein Z denotes a cation, such as H ⁺ (hydrogen). The above compound having the structural formula IVo (= 2- [2- [2-chloro-3- [2- (3,3-dimethyl-1- (4-sulfobutyl) -1,3-dihydro-2H-benzo [e ] indol-2-ylidenes) -ethylidenes] -1-cyclohexen-1-yl] -ethenyl] -3,3-dimethyl-1- (4-sulfobutyl) -3H-benzo [e] indolium Z) has maximum absorption at a wavelength of 819 nm and is commercially available from American Dye Source Inc. under the product name ADS830WS.

worin Z ein Kation bezeichnet, wie beispielsweise Na⁺ (Natrium). Die vorstehende Verbindung mit der Strukturformel IVp (=2-[2-[2-(4-amino-phenylsulfanyl)-3-[(3,3-dimethyl-1-(4-sulfobutyl)-1,3-dihydro-2H-indol-2-ylidene)-ethylidene]-1 -cyclohexen-1 -yl] -ethenyl] -3,3-dimethyl-1-(4-sulfobutyl)-3H-indolium Z) hat eine maximale Absorption bei einer Wellenlänge von 790 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS790WS.A compound having the structural formula IVp

wherein Z denotes a cation, such as Na ⁺ (sodium). The above compound having the structural formula IVp (= 2- [2- [2- (4-amino-phenylsulfanyl) -3 - [(3,3-dimethyl-1- (4-sulfobutyl) -1,3-dihydro-2H -indol-2-ylidenes) -ethylidene] -1-cyclohexene-1-yl] -ethenyl] -3,3-dimethyl-1- (4-sulfobutyl) -3H-indolium Z) has maximum absorption at a wavelength of 790 nm and is commercially available from American Dye Source Inc. under the product designation ADS790WS.

worin Z ein Kation bezeichnet, wie beispielsweise Na⁺ (Natrium). Die vorstehende Verbindung mit der Strukturformel IVq (= 2-[7-(3,3-dimethy-1-(4-sulfobutyl)1-1,3-dihydro-2H-benzo [e] indol-2-ylidene)-1,3,5 -heptatrienyl] -3,3 -dimethyl-1 -(4-sulfobutyl)-1H-benzo [e] indolium Z) hat eine maximale Absorption bei einer Wellenlänge von 785 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS785WS.A compound having the structural formula IVq

wherein Z denotes a cation, such as Na ⁺ (sodium). The above compound having the structural formula IVq (= 2- [7- (3,3-dimethy-1- (4-sulfobutyl) -1,3,3-dihydro-2H-benzo [e] indol-2-ylidenes) -1 , 3,5-heptatrienyl] -3,3-dimethyl-1- (4-sulfobutyl) -1H-benzo [e] indolium Z) has maximum absorption at a wavelength of 785 nm and is commercially available from American Dye Source Inc under the product name ADS785WS.

worin X ein Anion bezeichnet, wie beispielsweise SbF₆ (Antimonhexafluorid). Die vorstehende Verbindung mit der Strukturformel VIIIb (= 4,4',4"-tris(N,N-phenyl-3-methylphenylamino)-triphenylammonium X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 1075 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS1075A.A compound of structural formula VIIIb

wherein X denotes an anion, such as SbF ₆ (antimony hexafluoride). The above compound of structural formula VIIIb (= 4,4 ', 4 "-tris (N, N-phenyl-3-methylphenylamino) -triphenylammonium X) has a maximum absorption at 1075 nm wavelength as a solution in methanol and is commercial available from American Dye Source Inc. under the product name ADS1075A.

worin X^- ein Anion bezeichnet, wie beispielsweise ClO₄ ^- (Perchlorat) oder SbF₆ ^- (Antimonhexafluorid). Die vorstehende Verbindung mit der Strukturformel VIIIc (= N,N,N',N'-tetrakis(4-dibutylaminophenyl)-p-phenylen-diiminium 2X) hat als Lösung in Aceton eine maximale Absorption bei einer Wellenlänge von 1060 nm und ist kommerziell erhältlich von Organica Feinchemie GmbH, Wolfen, Deutschland unter der Produktbezeichnung Dye 1500.A compound of structural formula VIIIc

wherein X ^- denotes an anion, such as ClO ₄ ^- (perchlorate) or SbF ₆ ^- (antimony hexafluoride). The above compound having the structural formula VIIIc (= N, N, N ', N'-tetrakis (4-dibutylaminophenyl) -p-phenylene-diiminium 2X) has a maximum absorption at a wavelength of 1060 nm as the solution in acetone commercially available from Organica Feinchemie GmbH, Wolfen, Germany under the product name Dye 1500.

worin X^- ein Anion bezeichnet, wie beispielsweise ClO₄ ^- (Perchlorat) oder SbF₆ ^- (Antimonhexafluorid). Die vorstehende Verbindung mit der Strukturformel VIIId (= N,N,N',N'-tetrakis-(4-dibutylamino-phenyl)-p-benzochinon-bis-iminium 2X) hat als Lösung in Methanol eine maximale Absorption bei einer Wellenlänge von 1060 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS1065A.A compound of structural formula VIIId

wherein X ^- denotes an anion, such as ClO ₄ ^- (perchlorate) or SbF ₆ ^- (antimony hexafluoride). The above compound having the structural formula VIIId (= N, N, N ', N'-tetrakis- (4-dibutylamino-phenyl) -p-benzoquinone-bis-iminium 2X) has a maximum absorption at a wavelength of 1060 nm and is commercially available from American Dye Source Inc. under the product designation ADS1065A.

worin Z⁺ ein Kation bezeichnet, wie beispielsweise (C₄H₉)₄N⁺ (Tetrabutylammonium). Die vorstehende Verbindung mit der Strukturformel IXd (= Bis(3,6-dichlor-1,2-benzol-dithiolat)-nickelat Z) hat als Lösung in Aceton eine maximale Absorption bei einer Wellenlänge von 845 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS845MC.A compound having the structural formula IXd

wherein Z ⁺ denotes a cation, such as (C ₄ H ₉ ) ₄ N ⁺ (tetrabutylammonium). The above compound having the structural formula IXd (= bis (3,6-dichloro-1,2-benzene-dithiolate) nickelate Z) has as a solution in acetone a maximum absorption at a wavelength of 845 nm and is commercially available from American Dye Source Inc. under the product designation ADS845MC.

worin Z⁺ ein Kation bezeichnet, wie beispielsweise (C₄H₉)₄N⁺ (Tetrabutylammonium). Die vorstehende Verbindung mit der Strukturformel IXe (= bis(3,4,6-trichlor-1,2-benzol-dithiolat)-nickelat Z) hat als Lösung in Aceton eine maximale Absorption bei einer Wellenlänge von 865 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS870MC.A compound with the structural formula IXe

wherein Z ⁺ denotes a cation, such as (C ₄ H ₉ ) ₄ N ⁺ (tetrabutylammonium). The above compound having the structural formula IXe (= bis (3,4,6-trichloro-1,2-benzene-dithiolate) nickelate Z) has a maximum absorption at a wavelength of 865 nm as a solution in acetone and is commercially available from American Dye Source Inc. under the product name ADS870MC.

worin Z⁺ ein Kation bezeichnet, wie beispielsweise (C₄H₉)₄N⁺ (Tetrabutylammonium). Die vorstehende Verbindung mit der Strukturformel IXf (= bis(4-methyl-1,2-benzoldithiolat)-nickelat Z) hat als Lösung in Aceton eine maximale Absorption bei einer Wellenlänge von 892 nm und ist kommerziell erhältlich von American Dye Source Inc. unter der Produktbezeichnung ADS890MC.A compound having structural formula IXf

wherein Z ⁺ denotes a cation, such as (C ₄ H ₉ ) ₄ N ⁺ (tetrabutylammonium). The above compound having the structural formula IXf (= bis (4-methyl-1,2-benzenedithiolate) nickelate Z) has a maximum absorption at a wavelength of 892 nm as a solution in acetone and is commercially available from American Dye Source Inc. at the product name ADS890MC.

A compound having the structural formula IXg

The above compound of structural formula IXg (= bis (4,4'-dimethoxydithiobenzil) nickel) has a maximum absorption at 920 nm wavelength as a solution in acetone and is commercially available from American Dye Source Inc. under the product designation ADS920MC.

Instead of the abovementioned anions, the infrared absorbers according to the structural formulas IVf, IVg, IVh, IVi, IVj, IVk, IVI, VIIIc, VIIId may contain other monovalent, divalent, trivalent and higher-valued anions, for example Cl ^- , Br ^- , I ^- , HSO ₄ ^- , HSO ₃ ^- , ½SO ₄ ^2- , ½SO ₃ ^2- , CH ₃ SO ₃ ^- , CH ₃ C ₆ H ₄ SO ₃ ^- , NO ₃ ^- , HCOO ^- , CH ₃ COO ^- , H ₂ PO ₄ ^- , ½HPO ₄ ^2- , SCN ^- , BF ₄ ^- _, ClO ₄ ^- , SSO ₃ ^- , PF ₆ ^- , SbCl ₆ ^- , organic anions and mixtures of the above anions.

Instead of the aforementioned cations, the infrared absorbers according to the structural formulas IVm, IVn, IVo, IVp, IXd, IXe, IXf, IXg may contain other monovalent, divalent, trivalent and higher valued cations, such as H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , ½Mg ²⁺ , ½Ca ²⁺ , ½Sr ²⁺ , ½Ba ²⁺ , ⅓Al ³⁺ , NH ₄ ⁺ , organic cations and mixtures of the above anions.

According to the invention, one of the above compounds or a mixture of several of the above compounds is used as the infrared absorber.

wobei I(λ , z) die Intensität der elektromagnetischen Strahlung mit Wellenlänge λ, z die im Medium durchstrahlte Weglänge, ε(λ) den wellenlängenabhängigen Absorptionskoeffizienten des durchstrahlten Mediums und c die Dichte bzw. Konzentration des Mediums bezeichnet. Für eine polymere Folie mit einer Dicke d von weniger als 1 mm, die in normaler Richtung, d. h. senkrecht zu ihrer Oberfläche durchstrahlt wird, gelten für die transmittierte und absorbierte Intensität I_T(λ) und I_abs(λ) somit folgende Beziehungen (ii) und (iii) $$I_T\left(\lambda \right)=I_0\left(\lambda \right)e^{-\in \left(\lambda \right)\cdot c\cdot d}$$

$$I_{abs}\left(\lambda \right)=I_0\left(\lambda \right)\left(1-e^{-\in \left(\lambda \right)\cdot c\cdot d}\right)$$

The attenuation of the intensity of electromagnetic radiation of the wavelength λ, which is absorbed in a medium, can be described by the Lambert-Beer law (i) $$I\left(\mathrm{\lambda }\mathrm{.}z\right)=I_0\left(\mathrm{\lambda }\right)e^{-\mathrm{\epsilon }\left(\mathrm{\lambda }\right)\cdot c\cdot z}$$

where I (λ, z) designates the intensity of the electromagnetic radiation with wavelength λ, z the path length irradiated in the medium, ε (λ) the wavelength-dependent absorption coefficient of the irradiated medium and c the density or concentration of the medium. For a polymeric film with a thickness d of less than 1 mm, which is irradiated in the normal direction, ie perpendicular to its surface, the following relationships apply to the transmitted and absorbed intensity I _T (λ) and I _abs (λ) (ii ) and (iii) $$I_T\left(\lambda \right)=I_0\left(\lambda \right)e^{-\in \left(\lambda \right)\cdot c\cdot d}$$

$$I_{abs}\left(\lambda \right)=I_0\left(\lambda \right)\left(1-e^{-\in \left(\lambda \right)\cdot c\cdot d}\right)$$

The absorbed intensity I _abs (λ) as a function of the absorptivity ε (λ) · c · d of the film is in 1 shown graphically.

In the case of a thin, transparent and slightly absorbing film according to the invention, ie ε (λ) · c · d << 1, the relationship (iii) can be replaced to a good approximation by its linearized form (iv) $$I_{abs}\left(\lambda \right)=I_0\left(\lambda \right)\cdot \in \left(\lambda \right)\cdot c\cdot d$$

According to the relationship (iv), with a defined primary intensity I ₀ (λ), film condition or constant ε (λ) and film thickness d, the intensity I _abs (λ) absorbed in the film is proportional to the concentration c of the absorbing component (s). The radiation energy E _abs (λ) absorbed in the film per unit time Δt is proportional to the absorbed radiation intensity I _abs (λ), ie E _abs (λ) = I _abs (λ) · Δt. A certain part of the absorbed radiation energy in the film is converted into thermal energy, which causes an increase in temperature and possibly thermal decomposition and charring of the film. From the above consideration, especially the relationship (iv), it can be seen that the thermal energy deposited by absorbing electromagnetic radiation in a weakly absorbing film is proportional to the concentration c of the absorbing component.

$$\text{V}\sim {\text{I}}_0\left(\mathrm{\lambda }\right)\cdot \mathrm{\epsilon }\left(\mathrm{\lambda }\right)\cdot \text{c}\cdot \text{d}\cdot \mathrm{\Delta }\text{t}\cdot \left({\text{k}}_{\text{A}}\cdot {\text{C}}_{\text{FTA}}+{\text{k}}_{\text{B}}\cdot {\text{C}}_{\text{FTB}}\right)$$

If a sufficient amount of thermal energy is deposited in the film by means of electromagnetic radiation in order to thermally decompose and carbonize the polymeric material of the film, the degree of charring depends on the composition of the polymeric material of the film. In particular, the degree of charring is proportional to the proportions and char indices of the components making up the polymeric material. Is the polymeric material z. B. from two components A and B with concentration k _A , respectively k _B and charring index C _FTA , respectively C _FTB so for a given, absorbed in the film energy E _abs (λ) the degree of charring V is proportional to k _{A ·} C _FTA + k _B · C _FTB , ie it holds $$\text{V}~{\text{e}}_{\text{Section}}\left(\mathrm{\lambda }\right)\cdot \left({\text{k}}_{\text{A}}\cdot {\text{C}}_{\text{FTA}}+{\text{k}}_{\text{B}}\cdot {\text{C}}_{\text{FTB}}\right)$$

$$\text{V}~{\text{I}}_0\left(\mathrm{\lambda }\right)\cdot \mathrm{\epsilon }\left(\mathrm{\lambda }\right)\cdot \text{c}\cdot \text{d}\cdot \mathrm{\Delta }\text{t}\cdot \left({\text{k}}_{\text{A}}\cdot {\text{C}}_{\text{FTA}}+{\text{k}}_{\text{B}}\cdot {\text{C}}_{\text{FTB}}\right)$$

Examples

For experimental purposes, four-layer laser-writable composite films were produced, the structure of which in 2 is shown, wherein each of the laser active layers 1 and 4 and the white carrier layers 2 and 3 consist of films of the same type.

The four layers 1, 2, 3, 4 are laminated at a temperature of 130 ° C and 4 minutes pressing time to form a composite film with the in 2 to get shown construction. The films for the 100 μm thick laser-active layers 1 and 4 and for the 300 μm thick white carrier layers 2 and 3 are each produced by means of a roll calender.

The white carrier layer is made of a material having the following composition: Table 3: Composition of the white carrier layer component Wt .-% Cadence ^® copolyester GS5, amo rp hes glycol-modified polyethylene terephthalate, Eastman Chemical Company ^® 75.9 Impact additive based on methyl methacrylate-butadiene-styrene copolymer 9.3 Epoxidized soybean oil 0.3 High density oxidized polyethylene homopolymer 0.2 Loxiol ^® 3591, release agent Parafinbasis, Emery Oleochemicals Group 0.5 Process auxiliaries based on polymethylmethacrylate 2.8 wax 1.4 chalk 2.3 Titanium dioxide 7.4 total 100.0

For the laser-active layers 1 and 4 of the four-layer laser-writable composite films, a total of 13 films are produced from materials of different compositions. The composition of the various films Nos. 1-13 for the laser active layers 1 and 4 is shown in Table 4 below. Table 4: Composition of the films no. 1-13 for the laser-active layers Film for laser active layer, no. 1 2 3 4 5 6 7 8th 9 10 11 12 13 components Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Parts by weight Cadence ^® copolyester GS5 62 37 87 62 87 62 87 62 87 62 37 87 37 Lexan ^® SLX 1432, polycarbonate, Saudi Basic Industries Corporation 25 50 0 25 0 25 0 25 0 25 50 0 50 Impact additive based on methyl methacrylate-butadiene-styrene copolymer 8th 8th 8th 8th 8th 8th 8th 8th 8th 8th 8th 8th 8th Release agent in the form of a masterbatch of 77% by weight of polyester and 33% by weight of wax 4 4 4 4 4 4 4 4 4 4 4 4 4 Epoxidized soybean oil 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 High density oxidized polyethylene homopolymer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Loxiol ^® 3591 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 IR absorber I 0 0 0.5 0.5 0.7 0.7 0 0 0 0 0 0 0 IR absorber C 0 0 0 0 0 0 4 4 0 0 0 0 0 IR absorber S 0 0 0 0 0 0 0 0 1 1 1 3 3 Total parts by weight 100.0 100.0 100.5 100.5 100.7 100.7 104.0 104.0 101.0 101.0 101.0 103.0 103.0

The "I" type IR absorber consists of microscale mica particles coated with a layer of antimony-doped tin oxide (SnO ₂ : Sb). The "C" type of IR absorber is a microsphere pigment particle having a polycarbonate core and a shell of maleic anhydride compatibilized polyethylene and polypropylene, the core containing antimony trioxide (Sb ₂ O ₃ ). The type "S" IR absorber consists of micro-scale particles of a polymeric material containing as its main component polycarbonate and as an infrared-absorbing additive carbon black.

From the film for the white support layers 2 and 3 and each of the 13 different films No. 1-13 for the laser active layers 1 and 4 according to Table 4, a four-layer laser-writing composite film with the in 2 laminated structure shown.

Each of the 13 different composite films produced in this way is tested using a 15 kHz pulsed Nd-YAG labeling laser system of the Rofin company emitting a 1064 nm wavelength radiation with a test pattern of the type described in US Pat 3 labeled type.

This in 3 The laser marking pattern reproduced comprises 12 arrays, each having an area of 10 mm × 8 mm and being labeled with different operating parameters of the Nd-YAG marking laser system. The 12 fields are in the in 4 Numbered as shown.

The operating parameters of the Nd-YAG labeling laser system for labeling the fields 1-12 are shown in Table 5 below. Table 5: Operating parameters of the Nd-YAG laser marking system Field no. Writing grid [dpi] Interleave mode 1 400 y = 2, x = 1 2 450 y = 2, x = 1 3 500 y = 2, x = 1 4 400 unidirectional 5 450 unidirectional 6 500 unidirectional 7 400 y = 2, x = 1 8th 450 y = 2, x = 1 9 500 y = 2, x = 1 10 400 unidirectional 11 450 unidirectional 12 500 unidirectional

The blackening degree of the fields No. 1-12 of the laser inscription pattern of each of the 13 prepared laser-writing composite films 1-13 is measured by a densitometer according to FIG DIN 16536 and ISO 5 Measured in the reflection or remission mode. In the present invention, a device of the type RT 120 from Techkon GmbH is used for the densitometric measurement of the degree of blackening. The density degree D is calculated from the remission value R according to the relationship D = Ig (1 / R). By this relationship, high reflectance values give low density values and vice versa. The base density D ₀ = 0 is based on the remission R _{0 of} the film for the white carrier layers 2 and 3. Accordingly, the remission measured on the film for the white carrier layers 2 and 3 is set to R ₀ = 1 or the densitometric measuring device - in the present case a device of the RT 120 type - is calibrated accordingly.

In addition to the fields Nos. 1-12 of the laser marking pattern, densitometric measurement is also performed on an unlabelled area of the laser recordable composite sheets to determine the degree of blackening or haze of the laser active sheet 1 or 4, respectively. The corresponding densitometric measured values are subsequently marked with the note "Overlay" and, analogous to the fields No. 1-12, refer to the remission value R ₀ = 1 measured on the film for the white carrier layers 2 and 3.

Table 6 below shows densitometrically measured densities and optical density values for fields Nos. 6 and 9, a maximum density field, and an unspecified "overlay" region of each of the 13 laser-inscribed composite films produced. Table 6: Measured degrees of blackening (optical densities D) Composite foil no. 1 2 3 4 5 6 7 8th 9 10 11 12 13 overlay 0.11 0.13 0.15 0.13 0.16 0.14 0.11 0.11 0.15 0.13 0.16 0.26 0.20 Field no. 3 0.42 0.45 0.77 0.87 0.78 0.87 0.92 0.97 0.63 0.56 0.52 0.87 0.79 Field No. 9 0.37 0.39 0.63 0.70 0.64 0.75 0.86 0.83 0.56 0.84 0.59 0.81 1.10 Field with maximum blackness 0.42 0.45 0.77 0.89 0.78 0.91 0.92 0.97 0.63 0.91 1.14 0.87 1.29 Parts by weight of copolyester in laser-active position 62 37 87 62 87 62 87 62 87 62 37 87 37 Parts by weight of polycarbonate in laser-active position 25 50 0 25 0 25 0 25 0 25 50 0 50 Infrared absorber in laser-active position - - I I I I C C S S S S S Parts by weight infrared absorber - - 0.5 0.5 0.7 0.7 4.0 4.0 1.0 1.0 1.0 3.0 3.0

With regard to the type and parts by weight of the infrared absorber contained in the laser-active layer, the 13 composite films are assigned to six groups. Table 7: Grouping of the composite films group Composite foil no. 1 1.2 2 3.4 3 5.6 4 7.8 5 9, 10, 11 6 12, 13

Since polyester and polycarbonate only weakly absorb the infrared radiation emitted by the Nd-YAG laser marking system with a wavelength of 1064 nm, the thermal energy deposited by absorption in the 100 μm thin laser-active layer is determined primarily by the nature and the concentration or the parts by weight of the infrared absorber , Accordingly, when labeling the composite films Nos. 1-13 in the respective composite films belonging to one of the groups 1-6, approximately the same thermal energy is deposited in the laser-active layer or in the labeling fields 1-12.

With the same thermal energy deposited in the laser-active layer or in the labeling fields 1-12, the degree of charring depends solely on the content of copolyester and polycarbonate and the associated charring indices C _FT (see qualitative equation (vi) above).

The higher the degree of charring of the laser-active layer, the more the visible light incident on the composite foil and reflected by the white carrier layer is attenuated on its optical way back and forth through the laser-active layer. Accordingly, the optical remission is approximately inversely proportional to the degree of charring of the laser-active layer. Considering this relationship and the above relationship (vi), the densitometric data D shown in Table 6 and the associated remission values R for composite films in each of Groups 1-6 can be compared with each other. It should be noted that the densitometric measurements D and the reflectance values are logarithmically linked according to the relationship D = lg (1 / R) and 1 / R = 10 ^D, respectively.

The copolyester used in the laser active layer of the composite films 1-13 is glycol-modified polyethylene terephthalate (PETG). Accordingly, a char index C _FT = 1.25 is assumed for the copolyester (see Table 2). For the polycarbonate used in the laser active layer of composite films 1-13, C _FT = 5. According to the parts by weight of copolyester and polycarbonate, the following char indices result in arbitrary and relative units: Table 8: Charring indices of the laser active layer Parts by weight of copolyester 87 62 37 Parts by weight polycarbonate 0 25 50 C _FT [willk. Units] 87 × 1.25 = 108.75 62 × 1.25 + 25 × 5 = 202.5 37 × 1.25 + 50 × 5 = 296.25 C _FT [relative units] 1 1.9 2.7

Table 9 below shows the reciprocal remission values 1 / R and charring indices C _FT in relative units for the fields No. 3 and No. 9 of the composite films 3-13. Table 9: Remission values and charring indices Composite foil no. 3 4 5 6 7 8th 9 10 11 12 13 reciprocal remission value (1 / R) field no. 3 5.9 7.4 6.0 7.4 8.3 9.3 4.3 3.6 3.3 7.4 6.2 relative values (1 / R) field no. 3 1 1.3 1 1.2 1 1.1 1 0.8 0.8 1 0.8 reciprocal remission value (1 / R) field no. 9 4.3 5.0 4.4 5.6 7.2 6.8 3.6 6.9 3.9 6.5 12.6 relative values (1 / R) field no. 9 1 1.2 1 1.3 1 0.9 1 1.9 1.1 1 1.9 C _FT [relative units] 1 1.9 1 1.9 1 1.9 1 1.9 2.7 1 2.7

Claims (15)

Single or multilayer film with at least one laser-active layer of a polymeric material, characterized in that the material of the laser-active layer of - 35 to 80 wt .-% polyester; 10 to 65% by weight of a char forming tendency polymer of greater than 1.9 and 0.5 to 20% by weight of a char additive; 0 to 1% by weight of transesterification catalyst; 0.005 to 10% by weight of an infrared absorber for wavelengths greater than 780 nm; and from 1 to 20% by weight of other additives selected from color pigments, thermal stabilizers, polymeric modifiers, process aids and mixtures thereof; wherein the weight proportions are based on the total weight of the polymer material of the laser-active layer and total 100 wt .-% and the char additive is selected from aluminum phosphinate Al (H ₂ PO ₂ ) ₃ , aluminum isobutylphosphinate (CH ₃ ) ₂ CH-Al (H ₂ PO ₂ ) ₂ , tris (2-hydroxyethyl) -1,3,5-triazinetrione, organic halogen-free oxyimides containing at least one structural element of the formula IIIa

or mixtures of the above compounds. Slide after Claim 1 , characterized in that the polymer having a char index of greater than 1.9 is selected from polycarbonate, polyimide, polyetheretherketone, polyethylene naphthalate or a mixture of the above polymers. Slide after Claim 1 . 2 or 3 characterized in that the transesterification catalyst is selected from calcium acetate, magnesium acetate, zinc acetate, titanium tetrabutoxide, lanthanum (III) acetylacetonate, cobalt (II) acetylacetonate, lead acetate, hydrates of the above compounds and mixtures of the above compounds and their hydrates. Slide after Claim 1 . 2 . 3 or 4 , characterized in that the infrared absorber is selected from - micro- or nanoscale carbon black pigment (carbon black); - Metalloxiden, nickel oxide, tin oxide, antimony-doped tin oxide (SnO ₂ : Sb), titanium oxide, indium tin oxide (ITO), antimony oxide (Sb ₂ O ₃ ) and mixtures thereof, wherein the metal oxide is preferably nanoscale and / or on a micro- or nanoscale mineral carrier, in particular micro- or nanoscale bentonite or mica fixed and / or dispersed in micro-scale particles of a polymeric material; Aluminum-containing pigment having a metallic core with a content of elemental aluminum greater than or equal to 50 wt .-%, based on the weight of the metallic core, wherein the aluminum-containing pigment particles have a median diameter d ₅₀ between 0.5 and 25 have μm; - organic polymethine dyes, in particular organic cyanine dyes having the general structural formula (R ¹ N) - [CH = CH] _n CH = (N ⁺ R ¹ ) ↔ (R ¹ N ⁺ ) = CH [CH = CH] _n - (NR ¹ ) with 2 ≤ n ≤ 5, wherein (R ¹ N) and (N ⁺ R ¹ ) represent a nitrogen-containing heterocyclic group, such as imidazole, pyridine, pyrrole, quinone or thiazole, and the polyene chain CH [CH = CH] _n for stabilization optionally contains an aromatic ring system; - metal phosphates, copper (II) hydroxide phosphate,; Phthalocyanine, dithiolane or oxathiolane complexes of the metals Co, Cr, Cu, Fe, Ni, Pt or vandium oxide (VO); - Naphthaquinones and anthraquinones containing benzothiazole groups; - Squarylium dyes, in particular compounds having the structural formula Va

wherein R ^{2 represents} an aromatic ring system and (NR ³ ) or (N ⁺ R ³ ) nitrogen-containing groups; Croconium dyes, in particular compounds having the structural formula VIa or VIb

wherein R ^{4 represents} an aromatic ring system and (NR ⁵ ) or (N ⁺ R ⁵ ) nitrogen-containing groups; - Triphenylmethane dyes, in particular compounds having the structural formula VIIa or VIIb

Salts of the iminium cation, in particular a compound having the structural formula VIIIa

wherein X ^- represents an anion such as ClO ₄ ^- (perchlorate) or SbF ₆ ^- (antimony hexafluoride); Salts of the diimine cation, in particular compounds of the structural formula VIIIc (= N, N, N ', N'-tetrakis (4-dibutylaminophenyl) -p-phenylene-diiminium 2X)

wherein X ^- represents an anion such as ClO ₄ ^- (perchlorate) or SbF ₆ ^- (antimony hexafluoride); - Poly-3,4-ethylenedioxythiophene (PEDOT), in particular a compound of poly-3,4-ethylenedioxythiophene and polystyrenesulfonic acid; or mixtures of the above substances. Slide after Claim 1 or 2 , characterized in that the polyester of the laser active layer is an amorphous polyester. Slide after Claim 2 , characterized in that the polyester of the laser-active layer is glycolic or acid-modified polyethylene terephthalate. Slide after Claim 2 , characterized in that the polyester of the laser-active layer has a crystallization half-life of greater than 5 minutes, greater than 20 minutes, greater than 60 minutes or greater than 120 minutes. Foil after one or more of Claims 1 to 4 , characterized in that the laser-active layer has a thickness of 20 to 200 microns, 20 to 150 microns or 30 to 100 microns. Foil after one or more of Claims 1 to 5 , characterized in that the film comprises a carrier layer of a polymeric material and the laser-active layer is bonded to the carrier film by lamination. Slide after Claim 10 , characterized in that the polymeric material of the carrier layer to 40 to 90 wt .-% of polyester, based on the total weight of the polymeric material of the carrier layer. Slide after Claim 10 or 11 , characterized in that the polymeric material of the carrier layer contains 1 to 20 wt .-% of colored pigment, based on the total weight of the polymeric material of the carrier layer. Slide after Claim 10 . 11 or 12 , characterized in that the film comprises a disposed between the carrier layer and the laser-active layer color layer of a polymeric material and the color layer is laminated with the carrier layer and the laser-active layer. Slide after Claim 13 , characterized in that the polymeric material of the paint layer 40 to 90 wt .-% polyester and 1 to 20 wt .-% color pigments, wherein the weight fractions are based on the total weight of the polymeric material of the paint layer. Foil after one or more of Claims 1 to 14 , characterized in that the film comprises a cover layer of a polymeric material and the cover sheet is connected to the laser-active layer by lamination. Slide after Claim 15 , characterized in that the polymeric material of the cover layer to 40 to 95 wt .-% of polyester, based on the total weight of the polymeric material of the cover layer.

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