TWI383015B - Plastic molded bodies having two-dimensional or three-dimensional image structures produced through laser subsurface engraving - Google Patents

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 molded body having a two-dimensional or three-dimensional image structure manufactured by laser surface molding

The present invention relates to a plastic molded body having a two-dimensional or three-dimensional image structure which is internally molded by laser lower surface molding, and the plastic molded body is oxidized by a nano-sized metal having a particle diameter of 1 to 500 nm. The contents of the material are made of a plastic material, and the plastic material and the metal oxide included are transparent to the laser light used to fabricate the image structure.

The introduction of optical information into the plastic material itself by laser radiation is known per se. For this purpose, we distinguish between the laser marking and the laser surface molding.

The laser marks the plastic to act on the surface of the object and/or in the area closest to the surface. For this purpose, the absorption of laser energy directly interacting with the polymer or additives added to the plastic material, such as organic colorants or inorganic pigments that absorb laser radiation, plays a decisive role in the plastic material. In any case, chemical material changes and thus local visible discoloration of the plastic are produced by laser energy absorption.

Laser markability is a function of the specific wavelength absorption properties of the plastic material and/or its polymer based, the specific wavelength absorption properties of any laser sensitive additive, and the wavelength and radiant power of the laser radiation to be used. In addition to CO ₂ and excimer lasers, Nd:YAG lasers (ytterbium-doped yttrium aluminum garnet lasers) with characteristic wavelengths of 1064 nm and 532 nm are increasingly being used in this technology.

Laser-markable plastic materials containing laser-sensitive additives in the form of colorants and/or pigments generally have more or less pronounced color and/or translucency. Therefore, a molding compound used as a laser absorbent is usually equipped by introducing carbon black.

A highly transparent plastic material which is laser-markable by the addition of a nano-scale laser absorbent metal oxide is described in German Utility Model No. 20 2004 003362.3 and German Patent Application No. 10 2004 010504.9, which has not previously been disclosed.

The publications DE 44 07 547 and US 5,206,496 are cited as examples of glass and plastic lower surface engraving techniques which are transparent to the laser radiation of a laser beam.

Unlike laser marking, the laser's lower surface engraving will work at any depth of the material. It requires that the material be substantially transparent to incident laser radiation, as otherwise it would have been absorbed in the surface area.

In the process of focusing a laser beam having a sufficiently high power density inside the material itself which is transparent to the laser light, the thermal energy occurring in the laser focusing is limited due to the optical effect.

This thermal energy occurs to cause localized micro-cracks that are locally reluctant. This type of microcrack has a dot diameter of 25-40 microns. In transparent glass and plastics in visible light, at the edge of the crack, microcracks appear as bright spots due to daylight scattering.

The corresponding structures formed by individual microcracks can be combined in the workpiece by the deflection of the laser radiation by the mirror and the movement of the workpiece, and by the synchronization between the moving sequence and the laser pulse.

The pulse sequence frequency of a laser typically used for this purpose allows fabrication of structures up to about 1000 points per minute.

The starting point is the 3-D description of the graphic in the CAD program. The surface or the entire structure of the model is decomposed by the computer as a point cloud, and its individual points are implemented by laser beams as microcracks in glass or plastic. It shows that the more dense the point cloud is, the more accurate and clean the model is.

In the laser lower surface engraving process of a plastic using a laser that is transparent to the plastic, a mark in the form of microcracks inside the material is produced by corresponding focusing of the laser beam. Uncontrolled crack formation and crack propagation can occur in this case. It indicates that the material is weakened. Therefore, try to keep the weakening as small as possible.

In glass, this crack formation can even lead to the destruction of the later molded body, which sometimes occurs only days or weeks after the laser surface is molded.

In plastics, in addition to crack formation, localized destruction and carbonization of the material may occur, which is undesirable in surface molding of materials that are transparent in visible light due to deep discoloration.

Another problem with laser lower surface engraving using methods and materials according to the related art is that the precision of the fine gold silk decorative pattern in glass and plastic is insufficient. In theory, imaging accuracy can be improved by increasing the density of point clouds. However, for a certain point density, since the uncontrolled crack propagation actually extends to the next point and is no longer decomposed, the imaging accuracy is even impaired.

A method for crack-free laser lower surface engraving of laser pulses on the order of femtoseconds is described in US 5,761,111. However, lasers suitable for this purpose are not yet available for technical use and are additionally extremely expensive.

In US 6,537,479, the problem of crack formation is avoided since the laser marking is performed in the plasticized state of the material and the article remains in this state (encapsulated by the solid protective layer) or subsequently hardened. This method is very complicated and, in addition, in the case of subsequent hardening, the method is limited to materials that do not exhibit shrinkage after hardening, because otherwise the gold wire decorative geometry of the laser engraving will be destroyed again. This method is only available in a limited way for typical polymer materials in technical applications and is even extremely time consuming.

The present invention is therefore based on the discovery and provision of plastic materials in which two-dimensional or three-dimensional image structures can be fabricated using laser lower surface dicing while avoiding uncontrolled crack formation and crack propagation with significantly improved imaging accuracy. For this purpose, commercially available laser sources commonly found in technical applications will be used.

Surprisingly, it has been found in the interior of plastic molded bodies made of plastic materials having a nano-sized metal oxide content of from 1 to 500 nm, if irradiated with laser light (plastic materials and included) The metal oxide is transparent to the image to create an image, and the extremely fine and detailed three-dimensional image structure can be fabricated using a laser undersurface mold.

Therefore, the object of the present invention is a plastic molded body having a two-dimensional or three-dimensional image structure which is internally molded by a laser lower surface, which is distinguishable because the plastic molded body has a particle diameter of 1 to 500 nm. The nano-scale metal oxide is made of a plastic material, and the image structure is made of the laser light transparent plastic material used and the metal oxide included.

Further, the object of the present invention is a method for fabricating a two-dimensional or three-dimensional image structure by laser-surface molding into a plastic molded body, wherein the content of a nano-sized metal oxide having a particle diameter of 1 to 500 nm is contained. The molded body made of the plastic material of the object is irradiated with transparent laser light by the plastic material and the metal oxide included to produce an image.

It will be appreciated that the transparent plastic material is a material that is substantially transparent in the wavelength range of 300 to 1300 nm. A visible wavelength range of 400 to 800 nm is preferred. Corresponding materials are particularly suitable for introducing visually perceptible structures, such as art forms, through laser lower surface engraving. Further, a plastic material having a laser transparency in a wavelength range of 800 to 1300 nm is preferred. Corresponding materials that visually represent colored and/or opaque or fully opaque are suitable for introducing visually imperceptible structures through laser lower surface engraving, such as bar codes or material matrix codes for security purposes.

The transmittance of the plastic material in the selected wavelength range of commercially available laser sources found in typical technical applications is greater than 80%, preferably greater than 85%, and is preferably greater than 90%. The turbidity in the wavelength range of 400 to 800 nm is less than 5%, preferably less than 2%, and especially less than 1%. Transmittance and turbidity were determined according to ASTM D 1003.

It should be understood that the nanoscale metal oxides are all inorganic metal oxides, such as metal oxides, mixed metal oxides, mixed oxides, and mixtures thereof, which do not induce absorption or only in the characteristic wavelength range of the laser used. Produces a little absorption.

In short, it must be strictly ensured that the transparent plastic molded body and the nano-sized metal oxide are transparent to the laser light used.

The nanoscale is understood to mean that the largest dimension of the discrete particles of the laser-sensitive metal oxide is less than 1 micron, ie in the nanometer range. In this case, the size definition is related to all possible particle morphologies, such as initial particles, aggregates, and agglomerates.

The particle size of the laser-sensitive metal oxide is preferably from 1 to 500 nm and especially from 5 to 100 nm. If the selected particle size is less than 100 nanometers, the metal oxide particles themselves are no longer visible and do not impair the transparency of the plastic matrix.

In the plastic material, the content of the inorganic nanoparticles is suitably from 0.0001 to 0.1% by weight, preferably from 0.0005 to 0.05% by weight, and especially from 0.001 to 0.01% by weight, relative to the plastic material. For all plastic materials considered, controlled crack formation and thus visible lower surface markings with high imaging accuracy are typically produced in this concentration range.

Appropriate selection of the particle size and concentration within a particular range, even for matrix materials that are highly transparent in the visible wavelength range, can be dispensed with by impairing the inherent transparency. It is therefore advantageous to select a lower concentration range for nanoparticles having a particle size greater than 100 nanometers, and a higher concentration for nanoparticles having a particle size of less than 100 nanometers.

Preferably, the doping of indium oxide, doped tin oxide, doped zinc oxide, doped alumina, doped yttrium oxide and the corresponding mixed oxide are considered as inorganic nanoparticles for manufacturing a plastic material which can be marked by a lower surface by laser. Particles.

Nanoparticles having a particle size of less than 100 nanometers are also suitably used for opaque plastic materials which are irradiated in the wavelength range between 800 and 1300 nm to produce an image, as this can be achieved in a polymer matrix in this manner. A uniform distribution of metal oxides that is decisive for controlled crack formation.

Particularly suitable inorganic nanoparticles are indium tin oxide (ITO) or antimony tin oxide (ATO), and doped indium tin oxide and/or doped tin antimony oxide. Indium tin oxide is especially preferred, and is followed by "blue" indium tin oxide obtainable by a partial reduction process. Non-reducing "yellow" indium tin oxide allows the plastic material to have a visually perceptible yellowish color at higher concentrations and/or upper particle sizes, while "blue" indium tin oxide does not cause any appreciable color change. However, the observer believes that the light blue color is higher than the light yellow color.

The inorganic nanoparticles used in accordance with the present invention are known per se, and are even commercially available in dispersed form, even in nanoscale form (i.e., having a particle size of less than 1 micron and especially within the size range favored herein). In its delivery form, the inorganic nanoparticles are typically agglomerated. Aggregates having a particle size between 1 micrometer and several millimeters can be decomposed into nanoscale particles using strong shear. The degree of agglutination is determined as defined in DIN 53206 (August 1972).

Nano-sized metal oxides can be produced, for example, by thermal decomposition. Such methods are described, for example, in EP 1 142 830 A, EP 1 270 511 A or DE 103 11 645. Furthermore, the inorganic nanoparticles can be produced by precipitation, as described, for example, in DE 100 220 37.

In fact, nanoscale metal oxides can be incorporated into all plastic systems to provide them with markability. The plastic matrix is made of poly(meth)acrylate, polyamide, polyurethane, polyolefin, styrene polymer and styrene copolymer, polycarbonate, polyoxymethylene, polyimine, Polyfluorene, polyether oxime, polyketone, polyether ketone, polyetheretherketone, PEEK, polyphenylene sulfide, polyester (such as PET, PEN, PBT), polyoxymethylene, polyurethane, poly Plastic materials dominated by olefins or fluorinated polymers such as PVDF, EFEP, PTFE are typical. It is also possible to incorporate a blend containing the above-mentioned plastic as a component, or a polymer derived from such a kind, which is changed by subsequent reaction. Such materials are known in a variety of forms and are commercially available. Advantages of the invention according to the invention of inorganic nanoparticles are particularly manifested in highly transparent plastic systems, such as polycarbonate, transparent polyamides such as Grilamid TR55, TR90, Trogamid T5000, CX7323), polyethylene terephthalate, polyfluorene, polyether oxime, cycloolefin copolymer (Topas , Zeonex ), polymethyl methacrylate and its copolymers, as it does not affect the transparency of the material. Further, reference will be made to transparent polystyrene and polypropylene, as well as to partially crystalline plastics which can be processed into transparent molded bodies using nucleating agents or special processing conditions.

The transparent polyamines according to the invention are generally made from the following components: branched and unbranched aliphatic (6 C to 14 C atoms), alkyl substituted or unsubstituted cycloaliphatic (14 C to 22) C atom), araliphatic diamine (C 14-C 22) and aliphatic and cycloaliphatic dicarboxylic acid (C 6-C 44); the latter can be partially replaced by an aromatic dicarboxylic acid. In particular, the transparent polyamine can be additionally composed of monomer components having 6 C atoms, 10 C atoms, 11 C atoms and/or 12 C atoms, which are derived from indoleamine or ω-amine. Carboxylic acid.

The transparent polyamines according to the invention are preferably, but not exclusively, manufactured from the following components: glyceryl laurate or ω-aminododecanoic acid, sebacic acid, sebacic acid, dodecane Diacids, fatty acids (C18-C36; for example, under the trade name Pripol ), cyclohexanedicarboxylic acid and a partial replacement of such aliphatic acids (isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid or tributyl isophthalic acid). In addition, branched, unbranched or substituted forms of decanediamine, dodecanediamine, decanediamine, hexamethylenediamine, and representatives of the following types are used: alkyl substituted/unsubstituted cycloaliphatic di Amine bis-(4-aminocyclohexyl)-methane, bis-(3-methyl-4-aminocyclohexyl)-methane, bis-(4-aminocyclohexyl)-propane, bis-(amino group Cyclohexane), bis-(aminomethyl)-cyclohexane, isophoronediamine or even substituted pentamethylenediamine.

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

The highly transparent plastic system is mainly composed of polymethyl methacrylate, bisphenol-A-polycarbonate, polydecylamine and cycloolefin copolymer composed of norbornene and olefin, and can be utilized by means of the inorganic naphthalene according to the invention. The rice particles are laser-coated to allow surface marking without impairing material transparency.

Of course, nanoscale metal oxides can also be used in color highly transparent systems. The neutral intrinsic color of such additives allows for free choice of color and is particularly advantageous herein.

The transparent plastic material structurable by laser lower surface molding according to the present invention can be provided as a thick plate, a molded body, a semi-finished product or a molding compound. In this case, only a part of the thick plate, the molded body, the semi-finished product or the molding compound can also be embodied as a lower surface engraving by laser.

The plastic material which can be engraved from the lower surface of the laser is manufactured in a manner known per se in accordance with typical techniques and methods of plastics manufacturing and processing. In this case, it is possible to introduce a nanoparticle additive before or during the polymerization or condensation of the individual starting materials or starting material mixture, or even to add it in the reaction, to be known to the person skilled in the art. Manufacturing methods are used for related plastics. In the case of a polycondensate such as polyamine, the additive may, for example, be incorporated into one of the monomer components. The monomer component can then be subjected to a polycondensation reaction in a typical manner with the remaining reaction partners. In addition, after formation of the macromolecule, the resulting high molecular weight intermediate or finished product can be mixed with the nanoparticle additive, and all methods known to those skilled in the art can be used in this case.

Depending on the formulation of the plastic matrix material, liquid, semi-liquid and solid formulation components or monomers and such as polymerization initiators, stabilizers (such as ultraviolet (UV) absorbers, heat stabilizers), optical brighteners, anti- Additives, such as electrostatic agents, softeners, mold removers, lubricants, dispersants and antistatic agents, as well as fillers and reinforcing agents or impact modifiers, etc., may be mixed and homogenized, possibly molded It is then cured in a typical apparatus and apparatus (such as a reactor, a stirred vessel, a mixer, a roll mill, an extruder, etc.) for this purpose. For this purpose, nanoscale metal oxides are introduced into the material at appropriate times and uniformly incorporated. It is especially preferred to incorporate a nanoscale metal oxide in the form of a concentrated precursor mixture having the same or compatible plastic material.

It is advantageous if the nanoscale metal oxide is incorporated into the plastic matrix under high shear conditions in a plastic matrix. It can be carried out by appropriately setting the mixture, a roll mill or an extruder. In this way, any possibility of agglomeration or aggregation of the nano-sized metal oxide particles into larger units can be effectively avoided; any larger particles present are ground. The selection of the corresponding technology and specific method parameters is common to those skilled in the art.

Plastic molded bodies and semi-finished products can be obtained by injection molding or extrusion from a molding compound or by casting from a monomer and/or a prepolymer.

For example, the polymerization is carried out according to a method known to those skilled in the art by adding one or more polymerization initiators and inducing polymerization by heating or irradiation. A tempering step can be carried out after the polymerization in order to complete the reaction of the monomers.

After the plastic molded part is manufactured from a plastic material containing a nano-sized metal oxide, it can be marked by laser light irradiation.

The laser lower surface engraving can be performed on commercially available laser marking devices, such as from Cerion (Cerion X2, compact, green 532 nm), which has a write speed of 300 to 1000 dots per second and a pulse frequency of 3 It is kilohertz and has a pulse energy of 1 to 2 millijoules. The molded body to be molded is embedded in the device, and after being irradiated with the focused laser beam, a white to dark gray image structure having a clear outline and high contrast is obtained. The required settings can be determined without any other individual case.

For example, the following materials can also be used as laser crystals: Ti:Al ₂ O ₃ (wavelength can be set, from 680 to 1100 nm) Yb:YAG (wavelength 1030 nm, first harmonic: 515 nm, second harmonic Wave: 343 nm) Nd: YAG and Nd: Ce: Tb: YAG (wavelength 1064 nm, first harmonic: 532 nm, second harmonic: 355 nm) Ho: Cr: Tm: YAG (wavelength 2097) Nano, first harmonic: 1048.5 nm, second harmonic: 699 nm) Er: YAG (wavelength 2940 nm, first harmonic: 1470 nm, second harmonic: 980 nm)

Of course, a diode laser can also be used, which emits at wavelengths of 808 nm, 940 nm and 980 nm.

The use of a transparent plastic material in accordance with the present invention is particularly advantageous for the manufacture of plastic molded bodies having a three-dimensional image structure fabricated under the surface by a laser-depressed surface. In addition to technical applications, in particular, artistic purposes can also be achieved.

The transparent polymer can also be dyed. Appropriate use does not absorb the color of the laser light. Dyeing can be carried out as transparent, translucent or even soft.

If you use fluorescent pigments, you get a particularly interesting piece of art. By illuminating the edge of this type of artwork, you can create works that look like great value.

Hereinafter, the manufacture of the nanoparticle/plastic mixture and the execution of the lower surface engraving of the lower surface mark by the laser will be explained based on the polymethyl methacrylate and polyamine system as an example.

Example 1: Manufacture of cast polymethyl methacrylate blocks with 100 ppm indium tin oxide (PLEXIGLAS) GS)

1. Indium Tin Oxide Nano from Nanogate on a dual roll mill Polymix 110 L from Schwabenthan ITO IT-05 C5000 is dispersed in PMMA molding compound PLEXIGLAS 7N: 90 grams of PMMA molding compound PLEXIGLAS 7N was melted on a preheated two roll mill. The roll temperature of the front reel was 166 ° C, and the roll temperature of the rear reel was 148 ° C. Put another 90 grams of PMMA molding compound PLEXIGLAS 7N and 20 gram Nano ITO IT-05 C5000 was premixed and applied to a roll having about 5 grams of stearic acid. The rear reel can rotate slightly faster and thus create friction. Within 6 minutes, the rolled sheet was removed from the roll, folded, and placed on a roll, repeated 10 times. Subsequently, the rolled sheet is pulled from the roll, cooled and ground.

2. Using a rolled sheet to make a stock solution: The following materials were weighed in a 1 liter wide neck flask: 50.0 grams of 10% rolled sheet (from 1) 87.5 grams of dispersant (eg, from DEGUSSA AG/R Hm's PLEX 8684 F) 750.0 grams of MMA 750.0 grams of MMA/PMMA slurry having 25% PMMA having a molecular weight of 170,000 is a melt rolled sheet and a polymeric dispersant, the flask is sealed and shaken on a reel for 50 hours.

3. Manufacturing of polymeric raw materials: manufacturing with 0.01% Nano 1000 gram of polymerization raw material of ITO IT-05 C5000.

34.50 grams of stock solution 0.80 grams of initiator (2,2'-azobis-(2,4-dimethylvaleronitrile)) 0.20 grams to 1.0 grams of separating agent (lecithin) having 25% PMMA with a molecular weight of 170,000 960.00 g of MMA/PMMA slurry The polymerization starting material was stirred for 30 minutes, allowed to stand for 10 minutes, poured into a polymerization chamber, and then immediately placed in a water bath.

4. The polymerization chamber of the polymerization size of 10 x 200 x 200 mm in the polymerization chamber consists of two 6 mm thick floating flat glass plates, a remote cable and several metal clamps. The polymerization chamber is placed vertically, the polymeric material allows for slow movement and the chamber is sealed. The full polymerization chamber was placed horizontally in a water bath, heated to 45 to 50 ° C, and allowed to stand until the polymerization starting material polymerized into a solid compound. After removal of the clamp and the remote cable, the polymerization chamber was stopped for 4 hours in a tempering oven heated to 115 °C, then allowed to cool in the tempering box and removed from the mold.

The light transmittance in the visible range was 90%, and the turbidity was 1%. The material was internally labeled with a frequency doubled Nd:YAG laser (emission wavelength 532 nm, power level 3, duration 4 minutes).

Comparative example 2: Manufacture of undoped cast polymethyl methacrylate blocks (PLEXIGLAS) GS)

A method similar to the guide of Example 1 was used. In this case, only method steps 3 and 4 are performed. The rolled sheet can be dispensed with. The appropriate amount of stock solution from step 3 can be replaced by the corresponding amount of MMA/PMMA slurry.

The light transmittance in the visible range was 90%, and the turbidity was 1%.

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

Example 3: Production of polyamine/ITO compounds

Trogamid CX 7323 (Degussa AG, High Performance Polymers Division, commercial product of Marl) and Nanogate indium tin oxide Nano ITO IT-05 C5000 was compounded at a concentration of 0.01 weight percent on a Berstorff ZE 2533 D extruder at 300 ° C and pelletized. A slab having a size of 10 x 100 x 100 mm was produced from the pellet by injection molding.

The light transmittance in the visible range was 90%, and the haze was 1.5%.

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

Comparative Example 4: Manufacture of undoped polyamine thick plates

Injection molding from Trogamid CX 7323 (Degussa AG, High Performance Polymers Division, a commercial product of Marl) manufactured a slab having a size of 10 x 100 x 100 mm.

The light transmittance in the visible range was 90%, and the haze was 1.5%.

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

Example 5: Results of laser deep marking of PMMA compounds

The following images were fabricated from an internally molded molded body using a frequency doubled Nd:YAG laser (emission wavelength 532 nm).

Figure 1 shows the results of using the material of Example 1. A clear line pattern is produced in the ITO-doped polymer material.

Figure 2 shows the results of using the undoped polymer material of Example 2. The line structure can only be recognized with difficulty. The difference in imaging accuracy can be clearly seen.

Significantly better imaging accuracy can also be discerned in doped PMMA samples when writing letters.

Figure 3 shows the results of using the material of Example 1. In the doped material, individual points in the letter can be clearly distinguished. All points are separated from each other. The dots are not in contact with each other due to uncontrolled crack formation.

Figure 4 shows the results of using the undoped polymer material of Example 2. Here the letter "a" is interspersed with cracks and the edges are only obscured.

The superiority of the imaging accuracy of doped PMMA for laser lower surface engraving is also evident in comparison with lead crystal glass, which is commonly used for the art of making art by laser surface molding.

In Fig. 5 (from the material of Example 1), the point cloud pattern can be recognized with high imaging accuracy, and a very blurred line pattern is obtained in the lead crystal glass.

Figure 6 shows the results of the lower surface engraving in the lead crystal glass (same as the point cloud in Fig. 5).

The unusual imaging accuracy of doped PMMA was also observed in the third dimension.

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

Figure 8 shows the same image structure in a lead crystal block. About 10 lines are significantly wider and more offset than the lines in Figure 7.

Figure 1 shows the results of using the material of Example 1. A clear line pattern is produced in the ITO-doped polymer material.

Figure 2 shows the results of using the undoped polymer material of Example 2. The line structure can only be recognized with difficulty. The difference in imaging accuracy can be clearly seen.

Significantly better imaging accuracy can also be discerned in doped PMMA samples when writing letters.

Figure 3 shows the results of using the material of Example 1. In the doped material, individual points in the letter can be clearly distinguished. All points are separated from each other. The dots are not in contact with each other due to uncontrolled crack formation.

Figure 4 shows the results of using the undoped polymer material of Example 2. Here the letter "a" is interspersed with cracks and the edges are only obscured.

The superiority of the imaging accuracy of doped PMMA for laser lower surface engraving is also evident in comparison with lead crystal glass, which is commonly used for the art of making art by laser surface molding.

In Fig. 5 (from the material of Example 1), the point cloud pattern can be recognized with high imaging accuracy, and a very blurred line pattern is obtained in the lead crystal glass.

Figure 6 shows the results of the lower surface engraving in the lead crystal glass (same as the point cloud in Fig. 5).

The unusual imaging accuracy of doped PMMA was also observed in the third dimension.

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

Figure 8 shows the same image structure in a lead crystal block. About 10 lines are significantly wider and more offset than the lines in Figure 7.

Claims (16)

A plastic molded body having a two-dimensional or three-dimensional image structure which is internally molded by laser lower surface molding, characterized in that the plastic molded body is composed of a nano-sized metal oxide having a particle diameter of 1 to 500 nm. The contents are made of a plastic material that is transparent to the laser light used to fabricate the image structures. The plastic molded body of claim 1, characterized in that the metal oxides included in the plastic material have a particle diameter of 5 to 100 nm. A plastic molded body according to claim 1 or 2, which is characterized in that the metal oxide content is 0.0001 to 0.1% by weight relative to the plastic material. A plastic molded body according to claim 3, which is characterized in that the metal oxide content is from 0.001 to 0.01% by weight relative to the plastic material. A plastic molded body according to claim 1 or 2, characterized by doped indium oxide, doped tin oxide, doped zinc oxide, doped alumina or doped yttrium oxide as the nano-sized metal oxide In the plastic material. A plastic molded body according to claim 5, characterized in that indium tin oxide, antimony tin oxide or doped indium tin oxide or doped antimony tin oxide is contained in the plastic material as the nano-sized metal oxide. A plastic molded body according to claim 6, characterized in that blue indium tin oxide is contained in the plastic material as the nano-sized metal oxide. A plastic molded body according to claim 1 or 2, characterized in that the plastic matrix is copolymerized with poly(meth)acrylate, polyamine, polyurethane, polyolefin, styrene polymer and styrene. , polycarbonate, polyoxane, polyimine, polyfluorene, polyether oxime, polyketone, polyether ketone, polyphenylene sulfide, poly Ester, polyethylene oxide, polyurethane, polyolefin and chlorinated or fluorinated polymers. A plastic molded body according to claim 1 or 2, characterized in that the plastic matrix is mainly polymethyl methacrylate. A plastic molded body according to claim 1 or 2, characterized in that the plastic matrix is mainly bisphenol-A-polycarbonate. A plastic molded body according to claim 1 or 2, characterized in that the plastic matrix is mainly polyamide. A plastic molded body according to claim 1 or 2, characterized in that the plastic matrix is mainly a cycloolefin copolymer made of norbornene and an α-olefin. A plastic molded body according to claim 1 or 2, characterized in that the plastic molded body is transparent to laser light having a wavelength of from 300 to 1300 nm. A plastic molded body according to claim 13 which is characterized in that the plastic molded body is transparent to laser light having a wavelength of from 400 to 800 nm. A plastic molded body according to claim 13 which is characterized in that the plastic molded body is transparent to laser light having a wavelength of from 800 to 1300 nm. A method for fabricating a two-dimensional or three-dimensional image structure by laser imaging a lower surface of a plastic molded body, which is characterized by a plastic material having a content of a nano-sized metal oxide having a particle diameter of 1 to 500 nm. The molded body is formed by irradiating the transparent material with the plastic material and the metal oxide included to produce an image.