EP1856199A1

EP1856199A1 - Plastic moulding with bidimensional or tridimensional image structures generated by inner laser engraving

Info

Publication number: EP1856199A1
Application number: EP06743190A
Authority: EP
Inventors: Klaus-Dieter SCHÜBEL; Jürgen Kreutz; Wilhelm Wolff; Günther Ittmann; Thomas Hasskerl; Harald HÄGER; Ralf Richter; Wolfgang Stuber
Original assignee: Evonik Degussa GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2005-03-09
Filing date: 2006-02-16
Publication date: 2007-11-21
Anticipated expiration: 2026-02-16
Also published as: EP1856199B1; ES2308743T3; ATE397639T1; WO2006094881A1; DE502006000883D1; TW200643079A; TWI383015B; DE102005011180A1

Abstract

Plastic mouldings are disclosed with bidimensional or tridimensional image structures generated by inner laser engraving on their inside. The plastic mouldings are made of plastic materials with a content of nanoscale metal oxides having a particle size ranging from 1 to 500 nm. Both the plastic material and the metal oxide contained therein are transparent to the laser light used to generate the image structures. The plastic materials of which the mouldings are made contain, in particular, 0.001 to 0.1 % by weight metal oxides with a particle size ranging from 5 to 100 nm. Typical metal oxides are nanoscale indium tin oxide or antimony tin oxide.

Description

Plastic moldings with two-dimensional or three-dimensional image structures produced by laser engraving

description

The invention relates to plastic moldings with two- or three-dimensional image structures produced internally by internal laser engraving, wherein the plastic moldings consist of plastic materials which have a content of nanoscale metal oxides with a particle size of 1 to 500 nm, and both the plastic material and the metal oxide contained the laser light used to generate the image structures is transparent.

The introduction of optical information in plastic materials by laser radiation is known per se. A distinction is made between laser marking and laser engraving.

The marking of plastics by laser marking acts on the object surface or in the near-surface region. Decisive here is the absorption of the laser energy in the plastic material by direct interaction with the polymer or with an additive added to the plastic material, such as an organic dye or an inorganic pigment which absorbs the laser radiation. In any case, the absorption of the laser energy causes a chemical change in the material and thus a visible local discoloration of the plastic.

The laser markability depends on the wavelength - specific absorption behavior of the

Plastic materials or the underlying polymers, of the wavelength-specific Absorption behavior of any laser-sensitive additives as well as the wavelength and radiation power of the laser radiation to be used. In addition to CO ₂ and excimer lasers, Nd: YAG lasers (neodymium-doped yttrium aluminum Garnet lasers) with the characteristic wavelengths of 1064 nm and 532 nm are increasingly being used in this technique.

Laser-markable plastic materials which contain laser-sensitive additives in the form of dyes and / or pigments generally have a more or less pronounced coloring and / or lack of transparency. Often, the equipment is to be set as laser-absorbing molding compounds by the introduction of carbon black.

Highly transparent plastic materials which can be made laser-markable by adding nanoscale laser-absorbing metal oxides are described in German Utility Model 20 2004 003362.3 and in German patent application 10 2004 010504.9, which is not prior-published.

The technology of the inner engraving of transparent to laser radiation glasses and plastics by laser beams are exemplified the writings DE 44 07 547 and US 5,206,496.

In contrast to the laser marking, the laser engraving has to work in any depth of the material. This presupposes that the material is essentially transparent to the incident laser radiation, since otherwise it would already be absorbed in the surface region.

When focusing a laser beam of sufficiently high power density into the interior of the material which is transparent to the laser light, optical effects cause a limited development of thermal energy in the laser focus. This heat development results in locally limited microcracking in the material. Such microcracks have a dot diameter of 25-40 microns. In visible light transparent glasses and plastics, the microcracks appear as bright spots due to the scattering of daylight at the crack edges.

By deflecting the laser radiation via mirrors and the movement of the workpiece as well as by a synchronization between the movement sequence and the laser pulses corresponding structures can be composed of individual microcracks in the workpiece.

The pulse repetition frequency of the lasers typically used in this case allows the generation of structures with up to about 1000 points per minute.

The starting point is a 3D representation of the later motif in a CAD program. The surface or the entire structure of the model is computationally resolved as a point cloud whose individual points are converted by the laser beam in the glass or plastic as microcracks. The denser the point cloud through which the object is displayed, the more accurate and clean the model is mapped.

In the laser engraving of plastics with laser light, for which the plastic is actually transparent, a marking is generated in the interior of the material in the form of microcracks by appropriate focusing of the laser beam. This can lead to uncontrolled cracking and crack propagation. This is a weakening of the material. Therefore, it should be attempted to minimize this weakening.

In glass, this cracking can even lead to a subsequent destruction of the molding, some of which only days or even weeks after the laser engraving occurs. In plastics, in addition to the cracking, a local destruction of the material and carbonization may additionally occur, which is undesirable in the interior engraving of materials that are transparent in visible light because of the dark discoloration.

Another problem of laser engraving with methods and materials according to the prior art is the insufficient imaging accuracy in detailed, filigree patterns, both in glass and in plastics. Theoretically, one can see the imaging accuracy by increasing the

Improve point cloud density. In practice, however, the dots run into each other at a certain point density due to the uncontrolled propagation of cracks and are no longer resolved, so that the imaging accuracy even suffers.

No. 5,761,111 describes a method for crack-free internal laser engraving by laser pulses in the femtosecond range. However, suitable lasers for technical use are not yet available and would also be very expensive.

In US Pat. No. 6,537,479, the problem of crack formation is circumvented by performing the laser marking in the plasticized state of the material and either leaving the object in this state (covered by a solid protective cover) or subsequently hardening it. This method is very complex and also limited in the case of subsequent curing on materials that show no shrinkage during curing, otherwise the filigree geometry of the laser engraving would be destroyed again. On the common in technical application

Polymer materials, this process is only conditionally applicable and then with considerable overhead.

The present invention therefore an object of the invention to find plastic materials and to provide two-dimensional or three-dimensional image structures with significantly improved imaging accuracy by means of laser engraving while avoiding uncontrolled cracking and crack propagation. In this case, the commercially available commercially available laser sources should be used.

Surprisingly, it has been found that in the interior of plastic moldings, which consist of plastic materials which have a content of nanoscale metal oxides with a particle size of 1 to 500 nm, three-dimensional image structures of the highest fineness and detail can be produced by means of internal laser engraving, if laser light is used for that both the plastic material and the metal oxide contained is transparent, irradiated by imaging.

The invention thus relates to plastic moldings with two- or three-dimensional image structures produced in the interior by internal laser engraving, which are characterized in that the plastic moldings consist of plastic materials which have a content of nanoscale metal oxides with a particle size of 1 to 500 nm, wherein both the Plastic material and the metal oxide contained is transparent to the laser light used to generate the image structures.

The invention further relates to a process for the production of two- or three-dimensional image structures in the interior of plastic moldings by internal laser engraving, in which moldings consisting of plastic materials having a content of nanoscale metal oxides with particle size of 1 to 500 nm, with Laser light for which both the plastic material and the metal oxide contained is transparent, imagewise irradiated. Transparent plastic materials should be understood as meaning those which are essentially transparent in a wavelength range of 300 to 1300 nm. On the one hand, the visible wavelength range of 400 to 800 nm is preferred. Corresponding materials are particularly suitable for introducing visually perceptible structures by internal laser engraving, for example in the form of art objects. On the other hand, plastic materials with laser transparency in the wavelength range from 800 to 1300 nm are preferred. Corresponding materials which may also appear colored and / or opaque or completely opaque in their visual appearance are suitable for introducing visually imperceptible structures by internal laser engraving. for example as bar codes or data matrix codes for, for example, security purposes.

The transmission of the plastic material in the selected wavelength range of typically commercially used, commercially available laser sources should be greater than 80%, preferably greater than 85% and particularly preferably greater than 90%. The haze in the wavelength range from 400 to 800 nm should be less than 5, preferably less than 2 and in particular less than 1%. The determination of transmission and haze is carried out according to ASTM D 1003.

Nanoscale metal oxides are understood as meaning all inorganic-metallic oxides, such as metal oxides, metal mixed oxides, complex oxides and mixtures thereof, which cause little or no absorption in the characteristic wavelength range of the laser to be used.

Overall, care must be taken to ensure that both the transparent molded plastic body and the nanoscale metal oxide are transparent to the laser light to be used.

By nanoscale is meant that the largest dimension of the discrete particles of these laser-sensitive metal oxides smaller than 1 μm, that is in the nanometer range. This size definition refers to all possible particle morphologies such as primary particles as well as any aggregates and agglomerates.

Preferably, the particle size of the laser-sensitive

Metal oxides 1 to 500 nm and in particular 5 to 100 nm. When the particle size is below 100 nm, the metal oxide particles are no longer visible per se and do not affect the transparency of the plastic matrix.

In the plastic material, the content of inorganic nanoparticles is suitably 0.0001 to 0.1 wt.%, Preferably 0.0005 to 0.05 wt.% And particularly preferably 0.001 to 0.01 wt.%, Based on the plastic material. In this concentration range is usually and for all eligible

Plastic materials a controlled crack formation and thus a visible depth mark with high imaging accuracy causes.

With a suitable choice of particle size and concentration in the specified ranges is also in the visible

Wavelength range of highly transparent matrix materials excluded any impairment of intrinsic transparency. Thus, it is expedient for nanoparticles with particle sizes above 100 nm to choose the lower concentration range, while at particle sizes below 100 nm, higher concentrations can also be selected.

Suitable inorganic nanoparticles for the production of laser-deep-markable plastic materials are preferably doped indium oxide, doped tin oxide, doped zinc oxide, doped aluminum oxide, doped antimony oxide and corresponding mixed oxides.

Even with opaque plastic materials, which are irradiated in the wave range between 800 and 1300 nm nano particles with particle sizes of less than 100 nm are usefully used, since a homogeneous distribution of the metal oxides in the polymer matrix can be achieved, which is crucial for controlled crack formation.

Particularly suitable inorganic nanoparticles are indium tin oxide (ITO) or antimony tin oxide (ATO) and doped indium or antimony tin oxides. Particularly preferred is indium tin oxide, and in turn, the "blue" indium tin oxide obtainable by a partial reduction process. The unreduced "yellow" indium tin oxide may cause a visually perceptible slightly yellowish hue of the plastic material at higher concentrations and / or particle sizes at the top, while the "blue" indium tin oxide will not cause any discernible color change. At most, a faint blueness is observed, which is regarded by the viewer but rather as high quality, as a yellow cast.

The inorganic nanoparticles to be used according to the invention are known per se and are also commercially available in nanoscale form, that is to say with particle sizes below 1 μm, and in particular in the preferred size range, often in the form of dispersions. As supplied, the inorganic nanoparticles are generally agglomerated. The agglomerates, whose particle size is between 1 .mu.m and several mm, can be broken down into nanoscale particles by means of strong shearing. The determination of the Agglomerationagrades takes place in the sense of DIN 53206 (from August 1972).

Nanoscale metal oxides can be prepared, for example, by pyrolytic processes. Such processes are described, for example, in EP 1 142 830 A, EP 1 270 511 A or DE 103 11 645. Furthermore, inorganic nanoparticles can be prepared by precipitation processes, as described for example in DE 100 22 037. The nanoscale metal oxides can be incorporated into virtually any plastic system to impart laser markability. Typical are plastic materials in which the plastic matrix on poly (meth) acrylate, polyamide, polyurethane, polyolefins, styrene polymers and styrene copolymers, polycarbonate, silicones, polyimides, polysulfone, polyethersulfone, polyketones, polyether ketones, PEEK, polyphenylene sulfide, polyester (such as PET, PEN, PBT ), Polymethylene oxide, polyurethane, polyolefins or fluorine-containing polymers (such as PVDF, EFEP, PTFE). It is also possible to incorporate them into blends containing the above-mentioned plastics as components, or into polymers derived from these classes which have been modified by subsequent reactions. These materials are widely known and commercially available. The advantage according to the invention of the inorganic nanoparticles is found in particular in highly transparent plastic systems such as polycarbonates, transparent polyamides (for example Grilamid® TR55, TR90, Trogamid® T5000, CX7323),

Polyethylene terephthalate, polysulfone, polyethersulfone, cycloolefin copolymers (Topas®, Zeonex®),

Polymethyl methacrylate and their copolymers wear because they do not affect the transparency of the material. Furthermore, transparent polystyrene and polypropylene are to be mentioned, furthermore all semicrystalline plastics which can be processed by the use of nucleating agents or special processing conditions to transparent moldings.

The transparent polyamides of the invention are generally prepared from the building blocks: branched and unbranched aliphatic (6 C to 14 C atoms), alkyl-substituted or unsubstituted cycloaliphatic (14 C to 22 C atoms), araliphatic diamines (C14 - C22) and aliphatic and cycloaliphatic dicarboxylic acids (C6 to C44); The latter can be partly due to aromatic Dicarboxylic acids are replaced. In particular, the transparent polyamides may additionally consist of monomer units with 6 C atoms, 10 C atoms, 11 C atoms or 12 C atoms, which are derived from lactams or ω-aminocarboxylic acids.

Preferably, but not exclusively, the transparent polyamides according to the invention are prepared from the following building blocks: laurolactam or ω-aminododecanoic acid, azelaic acid, sebacic acid, dodecanedioic acid, fatty acids (C18-C36;

Trade name Pripol®), cyclohexanedicarboxylic acids, partial or partial replacement of these aliphatic acids by isoterephthalic acid, terephthalic acid, naphthalenedicarboxylic acid, tributylisophthalic acid. Furthermore, the use of decanediamine, dodecanediamine, nonanediamine, hexamethylenediamines branched, unbranched or substituted, and as representatives of the class of alkyl-substituted / unsubstituted cycloaliphatic diamines bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) - methane, bis (4-aminocyclohexyl) propane, bis (amino-cyclohexane), bis (aminomethyl) -cyclohexane, isophoronediamine or substituted pentamethylenediamines.

Examples of corresponding transparent polyamides are described, for example, in EP 0 725 100 and EP 0 725 101.

Particularly preferred are highly transparent plastic systems based on polymethyl methacrylate, bisphenol A polycarbonate, polyamide and so-called

Cycloolefin copolymers of norbornene and OC-olefins which can be made laser-marked with the aid of the inorganic nanoparticles according to the invention without impairing the transparency of the material.

Of course, the nanoscale metal oxides can also be used in colored high-transparency systems become. Here is particularly advantageous that the neutral color of these additives allows a free choice of color.

The transparent plastic materials which can be structured according to the invention by internal laser engraving can be present as plates, shaped bodies, semi-finished products or molding compositions. In this case, only a part of the plates, moldings, semi-finished products and molding compounds can be set laser-engravable inside.

The production of the laser-engravable plastic materials is carried out in a conventional manner according to common in plastics production and processing techniques and methods. It is possible to enter the nanoparticulate additives before or during the polymerization or polycondensation into individual starting materials or Eduktgemische or even during the reaction, wherein the known in the art specific manufacturing process for the plastics in question are used. In the case of polycondensates such as polyamides, for example, incorporation of the additive into one of the monomer components can take place. This monomer component can then with the other reactants in the usual way a

Polykondensationsreaktion be subjected. Furthermore, after the formation of macromolecules, the resulting high molecular weight intermediates or end products can be mixed with the nanoparticulate additives, it also being possible in this case for all methods familiar to the person skilled in the art to be used.

Depending on the formulation of the plastic matrix material liquid, semi-liquid and solid formulation ingredients or monomers and optionally required additives such as polymerization initiators, stabilizers (such as UV absorbers, heat stabilizers), optical brighteners, Anstistatika, plasticizers, mold release agents, lubricants, dispersing aids, antistatic agents but also Fillers and reinforcing agents or impact modifiers, etc. in customary devices and equipment such as reactors, stirred tanks, mixers, roll mills, extruders, etc. blended and homogenized, optionally shaped and then cured. The nanoscale

Metal oxides are introduced at the appropriate time in the material and incorporated homogeneously. Particularly preferred is the incorporation of the nanoscale metal oxides in the form of a concentrated masterbatch with the same or a compatible plastic material.

It is advantageous if the incorporation of the nanoscale metal oxides in the plastic matrix takes place under high shear in the plastic matrix. This can be done by appropriate adjustment of the mixer, roller mills, extruder. This will be a possible agglomeration or

Aggregation of nanoscale metal oxide particles effectively prevented larger units; any larger particles that are present are comminuted. The skilled worker is familiar with the corresponding techniques and the respective process parameters to be selected.

Plastic moldings and semi-finished products are obtainable by injection molding or extruding from molding materials or by casting from the monomers and / or prepolymers.

The polymerization is carried out by methods known to the person skilled in the art, for example by adding one or more polymerization initiators and inducing the polymerization by heating or irradiation. For the complete conversion of the monomer or monomers, an annealing step can follow the polymerization.

After production of plastic moldings from the nano-scale metal oxides containing plastic materials can be marked by irradiation with laser light. The internal laser engraving can be carried out on a commercially available laser marking device, for example from Cerion (Cerion X2, compact, green 532 nm) with a writing speed of 300 to 1000 points / s, a pulse frequency of 3 kHz and a pulse energy of 1 to 2 mJ , The shaped bodies to be engraved are placed in the device and, after irradiation with a focused laser beam, obtain white to dark gray image structures with sharp contours and high contrast. The required settings can be determined in individual cases without further ado.

As laser crystals, for example, the following materials may also be used:

Ti: A12O3 (wavelength adjustable from 680 to 1100 nm)

Yb: YAG (wavelength 1030 nm, 1st harmonic: 515 nm, 2nd harmonic: 343 nm)

Nd: YAG and Nd: Ce: Tb: YAG (wavelength 1064 nm, 1st harmonic: 532 nm, 2nd harmonic: 355 nm)

Ho: Cr: Tm: YAG (wavelength 2097 nm, 1st harmonic: 1048.5 nm, 2nd harmonic: 699 nm)

Er: YAG (wavelength 2940 nm, 1st harmonic: 1470 nm, 2nd harmonic: 980 nm)

Of course, diode lasers emitting at wavelengths of 808, 940 and 980 nm can also be used.

The transparent plastic materials can according to the invention very advantageous for the production of

Plastic moldings with three-dimensional image structures produced under the surface by internal laser engraving be used. In addition to technical applications, in particular, artistic objects can be realized.

The transparent polymers can also be colored. It makes sense to use colors that match the laser light do not absorb. The coloring can be transparent, translucent but also covered.

Particularly interesting art objects are obtained when fluorescent dyes are used. By illuminating the edges of such art objects particularly valuable appearing art objects can be produced.

In the following, the production of nanoparticles / plastic mixtures and the implementation of the interior engraving by laser depth marking is an example

Polymethylmethacrylat- and polyamide systems are explained.

Example 1:

Production of a cast polymethyl methacrylate block (PLEXIGLAS® GS) with 100 ppm indium tin oxide

1. Dispersion of indium tin oxide Nano.IT0 IT-05 C5000 from Nanogate in PMMA molding compound PLEXIGLAS® 7N on a two-roll mill Polymix 110 L from Schwabenthan:

90g PMMA molding compound PLEXIGLAS® 7N are melted on the preheated two-roll mill. The roll temperature is on the front roller 166 ⁰ C and G on the rear roller 148 ⁰ C. Another 90 PMMA molding composition PLEXIGLAS 7N be premixed with 20g Nano®ITO IT-05 C5000 and loaded with about 5g of stearic acid on the rollers. The rear roller is rotated a little faster, creating a friction. Within 6 minutes, the rolled sheet is pulled off the roll 10 times, folded and returned to the roll. Then you pull the roller skin from the roller, allowed to cool and crushed. 2. Preparation of a stock solution with the rolled skin:

Weigh into a 11 wide mouth bottle:

50.0 g 10% roller skin (from 1.)

87.5 g dispersing agent (eg PLEX® 8684 F from DEGUSSA AG / Röhm)

750.0 g MMA

750.0 g MMA / PMMA syrup with 25% PMMA with MW of 170000

To loosen the roller skin and the polymeric dispersant, the bottle is closed and rolled on a roll bar for 50 hours.

3. Preparation of the polymerization batch:

Preparation of the polymerization batch of 1000 g with 0.01 ^! Nano® ITO IT-05 C5000.

34.50 g stock solution

0.80 g initiator (2,2'-azobis (2,4-dimethylvaleronitrile)

0.20 g to 1.0 g of release agent (lecithin)

960.00 g MMA / PMMA syrup with 25% PMMA with MW of 170000

The polymerization mixture is stirred for 30 min, allowed to stand for 10 min, filled into the polymerization and then immediately placed in a water bath.

4. Polymerization in a polymerization chamber From two 6mm thick float glass panes, a spacer cord and some metal clips, a polymerization chamber size of 10 x 200 x 200 mm size is built. The polymerization is set up vertically, allowed to run slowly the polymerization mixture and sealed the chamber. The filled polymerisation is horizontally inserted into the to 5O ⁰ C heated water bath at 45 and as long are allowed to be polymerized to the polymerization mixture into a solid mass. After removal of the clamps and the spacer cord, the polymerization chamber is 4h end polymerized in a pre-heated to 115 ⁰ C tempering, then allowed to cool in a tempering and removed from the mold.

Visible light transmission is 90% and Haze 1%.

The material was laser-marked with a frequency-doubled Nd: YAG laser (emission wavelength 532 nm power level 3, duration 4 min).

Comparative Example 2:

Production of an undoped cast polymethyl methacrylate block (PLEXIGLAS® GS)

The procedure is analogous to the procedure of Example 1. Only the process steps 3 and 4 are carried out. On the production of a rolled sheet can be omitted. The appropriate amount of stock solution from step 3 can be replaced by an appropriate amount of MMA / PMMA syrup.

Visible light transmission is 90% and Haze 1%. The material was laser-marked with a frequency-doubled Nd: YAG laser (emission wavelength 532 nm, power level 3, duration 4 min).

Example 3:

Production of a polyamide / ITO compound

Trogamid® CX 7323, a commercial product of Degussa AG, Business Unit High Performance Polymers, Mari, is coated with nano-scale indium tin oxide Nano® IT0 05-C5000 from Nanogate in a concentration of 0.01 wt.% On a Berstorff ZE 2533 D extruder 300 ⁰ C compounded and granulated. From the granules plates were produced by injection molding with the dimensions 10 x 100 x 100 mm.

The light transmission in the visible range is 90% and the Haze 1.5%.

The material was laser-marked with a frequency-doubled Nd: YAG laser (emission wavelength 532 nm, power level 4, duration 1 min).

Comparative Example 4

Production of undoped polyamide plates

From Trogamid® CX 7323, a commercial product of Degussa AG, Business Unit High Performance Polymers, Mari, plates with the dimensions 10 x 100 x 100 mm were produced by injection molding.

The light transmission in the visible range is 90% and the Haze 1.5%. The material was laser-marked with a frequency-doubled Nd: YAG laser (emission wavelength 532 nm, power level 4, duration 1 min).

Example 5:

Results of the laser depth marking on PMMA compounds

The following images were prepared from internally engraved molded articles using a frequency-doubled Nd: YAG laser (emission wavelength 532 nm).

Figure 1 shows the result with the material

Example 1. A clear line pattern was produced in the polymer material doped with ITO.

Figure 2 shows the result with the undoped polymer material from Example 2. A line structure is difficult to detect. The differences in the

Imaging accuracy can be clearly seen.

Even when writing letters a significantly better imaging accuracy of the doped PMMA samples can be seen.

Figure 3 shows the result with the material from example 1. With the doped material every single point in the letter is clearly visible. All points are separated. A confluence of dots due to uncontrolled cracking is not observed.

Figure 4 shows the result with the undoped polymer material from Example 2. Here, the letter "a" is traversed by cracks and the edge appears very blurred. In comparison to lead crystal glass, which is commonly used for the production of art objects by laser engraving, the superiority of the imaging accuracy of doped PMMA in laser engraving is clearly visible.

While in Figure 5 (material of Example 1) the point cloud pattern can be seen with high imaging accuracy, a very blurred line pattern is obtained in the lead crystal glass. Figure 6 shows the result of the interior engraving in lead crystal glass (same point cloud file as in Figure 5).

The outstanding imaging accuracy of the doped PMMA is also observed in the third dimension.

Figure 7 shows the side view of the letter "S" from Figure 5 (material from Example 1). A line pattern of approximately 10 lines that are completely separated from each other can be observed.

Figure 8 shows the same image structure in the lead crystal block. The approximately 10 lines are much wider and more offset than the lines in Figure 7.

Claims

claims

1. plastic moldings with internally by internal laser engraving produced two- or three-dimensional image structures, characterized in that the plastic moldings consist of plastic materials having a content of nanoscale metal oxides with particle size of 1 to 500 nm, wherein both the plastic material and the contained Metal oxide is transparent to the laser light used to generate the image structures.

2. Plastic molding according to claim 1, characterized in that the particle size of the metal oxides contained in the plastic material is 5 to 100 nm.

3. Plastic molding according to claims 1 or 2, characterized in that the content of metal oxides 0.0001 to 0.1 wt .-%, preferably 0.001 to 0.01% by weight, based on the plastic material, is.

4. Plastic molding according to claims 1 to 3, characterized in that in the plastic material as nanoscale metal oxide doped indium oxide, doped tin oxide, doped zinc oxide, doped aluminum oxide or doped antimony oxide is included.

5. Plastic molding according to claim 4, characterized in that contained in the plastic material as nanoscale metal oxide indium tin oxide, antimony tin oxide or doped indium or antimony tin oxides.

6. Plastic molding according to claim 5, characterized in that contained in the plastic material as nanoscale metal oxide blue indium tin oxide.

7. Plastic molding according to claims 1 to 6, characterized in that the plastic matrix on poly (meth) acrylate, polyamide, polyurethane, polyolefins, styrene polymers and styrene copolymers, polycarbonate, silicones, polyimides, polysulfone, polyethersulfone, polyketones, polyether ketones, polyphenylene sulfide, polyester , Polyethylene oxide, polyurethane, polyolefins and chlorine- or fluorine-containing polymers.

8. Plastic molding according to claims 1 to 7, characterized in that the plastic matrix is based on polymethylmethacrylate.

9. Plastic molding according to claims 1 to 7, characterized in that the plastic matrix is based on bisphenol A polycarbonate.

10. Plastic molding according to claims 1 to 7, characterized in that the plastic matrix is based on polyamide.

11. Plastic moldings according to claims 1 to 7, characterized in that the plastic matrix based on cycloolefin copolymers of norbornene and 0C olefins.

12. Plastic molding according to claims 1 to 11, characterized in that the plastic molding for laser light of the wavelength of 300 to 1300 nm is transparent.

13. Plastic molding according to claim 12, characterized in that the plastic molding for laser light of the wavelength of 400 to 800 nm is transparent.

14. Plastic molding according to claim 12, characterized in that the molded plastic body for Laser light of wavelength from 800 to 1300 nm is transparent.

15. A process for the production of two- or three-dimensional image structures in the interior of plastic moldings by internal laser engraving, characterized in that molding bodies, which consist of plastic materials which have a content of nanoscale metal oxides with particle size of 1 to 500 nm, with laser light for that both the plastic material and the metal oxide contained is transparent, irradiated by imaging.