HK1098428B - Highly transparent laser-markable and laser-weldable plastic materials - Google Patents

Description

High-transparency laser-markable and laser-weldable plastic material

Technical Field

The present invention relates to highly transparent plastic materials which are capable of laser-markable and/or laser-weldable due to the presence of nanoscale laser-sensitive metal oxides, to a process for the preparation of such plastic materials and to the use thereof.

Background

The identification of plastics by laser marking and the welding of plastics also using laser energy are known per se. Both of these are caused by the absorption of laser energy in the plastic material either directly through interaction with the polymer or indirectly using a laser sensitive agent added to the plastic material. The laser-sensitive agent may be an organic colorant or pigment which causes a locally significant discoloration of the plastic material by absorption of laser energy. It may be a compound which changes from an invisible, colorless form to a visible form upon irradiation with laser light. In laser welding, the plastic material is strongly thermalized in the connecting region by absorption of laser energy so that the material melts and the two parts are welded to each other.

Identification of production products is becoming increasingly important in almost all branches of industry. To such an extent that, for example, production date, lot number, expiration date, product identification, bar code, company logo, etc. must be used. Laser marking is significantly faster than conventional identification techniques such as printing, embossing, stamping and labeling, since it does not require a touch operation and is therefore more accurate and can be applied to even uneven surfaces without further measurement. Since laser markings are produced subsurface in the material, they are permanent, stable and significantly more resistant to deletion, alteration or even counterfeiting. For this reason, contact with other media, for example in a liquid container and closed, is also immaterial-the first requirement being that the plastic matrix be resistant. The safety and permanence of product identification, as well as freedom from contamination, are of particular importance, for example, in the packaging of pharmaceuticals, foods and beverages.

In practice, the principle of the formation of a compound between the connection portions in laser welding is based on the fact that the connection portions facing the laser source have a transparency sufficient for the light of the laser source having a specific wavelength to enable the radiation to reach the connection portions situated below where the radiation is absorbed. Due to this absorption, heat is released so that in the contact area of the connecting portion, not only the absorbing material but also the transparent material is locally melted and partially mixed, by which cooling a composite is formed. As a result of which the two parts are welded to one another in this manner.

Laser markability or laser weldability is a function of the nature of the plastic material and/or polymer on which it is based, the nature and content of all laser-sensitive additives, and also the wavelength and radiation energy of the laser used. In addition to carbon dioxide and excimer lasers, Nd: YAG lasers (neodymium-doped yttrium-aluminum-garnet lasers) with typical wavelengths of 1064nm and 532nm are increasingly used in this technology, even diode lasers being used in recent years. In laser marking, good recognizability-as dark as possible in front of a bright background-and a high contrast are desirable.

Laser-markable or laser-weldable plastic materials containing laser-sensitive additives in the form of colorants and/or pigments, generally have a more or less pronounced coloring effect and/or opacity. In the case of laser welding, the molding compounds used to prepare the laser absorbers are most often prepared in this way by incorporating carbon black.

For example, laser-markable plastic materials comprising pigments made of doped tin oxide containing electrically conductive layers are described in EP 0797511B 1. These pigments are contained in the material in concentrations of 0.1 to 4% by weight, based on a transparent or translucent matrix in the form of platelets, in particular layered silicates such as mica. Transparent thermoplastic materials containing such pigments exhibit metallic shimmer, which can, however, be completely masked by the addition of masking pigments. Thus, laser-markable plastic materials of high transparency can be prepared without the use of such pigments.

In WO 01/00719, laser-markable products are described which comprise antimony trioxide having a particle size of more than 0.5 μm as laser-marking pigment. A dark mark on a bright background and a good contrast can be obtained. However, due to the particle size of the pigment, the product is no longer transparent.

Only a few polymer systems are inherently laser markable or laser weldable without further addition of laser sensitive additives. For this purpose, polymers containing a ring-shaped or aromatic structure which are prone to carbonisation under the action of laser radiation are preferably used. Such polymeric materials are not resistant to weathering due to their composition. The contrast of the inscription is poor and can only be improved by the addition of laser-sensitive particles or colorants. These polymeric materials are also not weldable due to the lack of laser transparency.

WO 98/28365 describes a laser-markable polymer composition made of polymethacrylate containing acrylate comonomers and a second polymer made of styrene and maleic anhydride, which may further contain additives. Due to the content of styrene and maleic anhydride, no additional laser-sensitive pigments are required. The molded article has a haze of about 5-10%. Plastic molded bodies having a haze of approximately 5 to 10% do not meet the existing requirements, however. Haze of less than 1%, or at least less than 2%, is necessary for high transparency requirements.

DE 10054859 a1 describes a method for laser welding of plastic molded parts, in which a laser beam is guided through a laser-transparent molded part I and is caused to heat in a laser-absorbing molded part II, so that welding takes place. The molded article comprises laser-transparent and laser-absorbent colorants and pigments, in particular carbon black, which cooperate with one another in such a way that a homogeneous color undertone is produced. The material is naturally opaque.

Highly transparent laser-markable and laser-weldable plastic materials, in particular those additionally resistant to weathering, are not known from the prior art.

Disclosure of Invention

The invention is therefore based on the object of providing a laser-markable and laser-weldable plastic material with high transparency. In particular, these materials for laser-sensitive additives for plastic materials can be used to make laser-markable and/or laser-weldable materials without impairing the transparency of the materials.

The inventors have surprisingly found that highly transparent plastic materials can be made laser markable and/or laser weldable plastic materials without compromising transparency by incorporating an amount of a nano-scale laser sensitive metal oxide.

The object of the present invention is therefore highly transparent plastic materials which are characterized in that they are laser markable and/or laser weldable due to the fact that they contain laser-sensitive metal oxides on a nanoscale.

The object of the present invention also includes the use of laser-sensitive metal oxides of nanometric dimensions for the preparation of high transparency laser-markable and/or laser-weldable plastic materials.

Furthermore, the object of the present invention consists of a process for the preparation of high-transparency laser-markable and/or laser-weldable plastic materials by means of nanoscale, laser-sensitive metal oxides which are incorporated into the plastic matrix under the action of high shear.

The present invention is based on the recognition that laser marking pigments known from the related art are unsuitable for use in high transparency systems in terms of their particle size and their morphology, since they typically exceed the critical dimension of one quarter of the wavelength of visible light of about 80nm to a great extent. Laser-sensitive pigments having particle sizes with primary particles below 80nm are well known, but these are not provided in the form of isolated primary particles or small aggregates, as is the case in carbon black, but are obtained, for example, only as highly aggregated, partially aggregated particles having a considerably larger particle diameter. The known laser marking pigments therefore lead to considerable light scattering and thus to a whitening of the plastic material.

According to the invention, laser-sensitive metal oxides of nanometric dimensions are incorporated into plastics materials, in particular those which are inherently highly transparent, in order to make them laser-markable and/or laser-weldable plastics materials.

High-transparency plastic materials are understood to be those which have a transmission of more than 85%, in particular more than 90%, and a haze of less than 3%, preferably less than 2%, in particular less than 1%, at a material thickness of 2 mm. Transmission and haze were measured according to ASTM D1003.

Laser-sensitive metal oxides are understood to be all inorganic metal oxides such as metal oxides, mixed metal oxides and complex oxides which absorb in the characteristic wavelength range of the laser used and are thus capable of producing locally visible changes in the plastic matrix into which they are incorporated.

Nanoscale is understood to mean that the largest diameter of discrete particles of these laser-sensitive metal oxides is less than 1 μm, i.e. in the nanometer range. In this case, this size definition relates to all possible particle morphologies such as primary particles and possible aggregates and agglomerates. The particle size of the laser sensitive metal oxide is preferably 1 to 500nm, particularly 5 to 100 nm. If the particle size is chosen below 100nm, the metal oxide particles are no longer visible as such and do not impair the transparency of the plastic matrix.

The content of the laser-sensitive metal oxide in the plastic material is preferably 0.0001 to 0.1 wt%, more preferably 0.001 to 0.01 wt%, based on the plastic material. In this concentration range, sufficient laser-markability or laser-weldability of the plastic matrix usually results for all plastic materials initially considered.

If the particle size and concentration are appropriately selected within the given ranges, damage to the intrinsic transparency can be avoided even for high-transparency matrix materials. It is thus preferred to select a lower concentration range for laser-sensitive pigments having a particle size above 100nm, while higher concentrations may also be selected for particle sizes below 100 nm.

Doped indium oxide, doped tin oxide and doped antimony oxide are preferably initially considered as laser-sensitive metal oxides on the nanoscale for producing laser-markable and/or laser-weldable plastic materials of high transparency.

Particularly suitable metal oxides are indium-tin oxide (ITO) or antimony-tin oxide (ATO) and doped indium-tin and/or antimony-tin oxides. Indium-tin oxide is particularly preferred and its "blue" indium-tin oxide can in turn be obtained by a partial reduction process. The non-reduced "yellow" indium-tin oxide may lead to a visually perceptible slight yellow spot of the plastic material at higher concentrations and/or particle sizes in the upper range, whereas the "blue" indium-tin oxide does not cause any visible color change.

The laser-sensitive metal oxides to be used in accordance with the invention are well known per se and are commercially available even in nanoscale form, i.e. as discrete particles having a size below 1 μm, in particular in the size range preferred here, usually in the form of a dispersion.

The laser-sensitive metal oxide is typically provided as agglomerated particles, for example, as agglomerates whose particle size can range from 1 μm to several millimeters. These agglomerates can be incorporated into a plastic matrix using the method according to the invention under strong shear, wherein the agglomerates are broken up into primary particles of nanometric dimensions.

The degree of agglomeration was determined according to DIN 53206 (8.1972).

Nanoscale metal oxides can be prepared in particular, for example, by pyrogenic processes. Such a process is described, for example, in EP 1142830A, EP 1270511 a or DE 10311645. Furthermore, nanoscale metal oxides can also be prepared by precipitation methods, for example as described in DE 10022037.

Nanoscale laser-sensitive metal oxides can be mixed into almost all plastic systems to provide their laser markability or laser weldability. Plastic materials in which the plastic matrix is based on poly (meth) acrylates, polyamides, polyurethanes, polyolefins, styrene polymers and styrene copolymers, polycarbonates, silicones, polyimides, polysulfones, polyether sulfones, polyketones, polyether ketones, PEEK, polyphenylene sulfides, polyesters (such as PET, PEN, PBT), polyethylene oxides, polyurethanes, polyolefins or polymers containing fluorine (such as PVDF, EFEP, PTFE) are customary. It is also possible to mix them into dopes which comprise the abovementioned plastics materials as constituents, or into polymers which are derived from such polymers by subsequent reaction. These materials are well known and commercially available in a variety of forms. The advantages of the nanoscale metal oxides according to the invention are particularly attributed to the high transparency of plastic systems such as polycarbonates, transparent polyamides (e.g.Grilamid)TR55、TR90、TrogamidT5000, CX7323), polyethylene terephthalate, polysulfone, polyethersulfone, cycloolefin copolymer (Top)as、Zeonex) Polymethacrylates and their copolymers, since they do not affect the transparency of the material. Furthermore, transparent polystyrene and polypropylene and crystalline plastics which can be processed in all parts into transparent films or mouldings by using nucleating agents or special processing conditions can be cited.

The transparent polyamides according to the invention are generally prepared from the following components: branched and unbranched aliphatic (6 to 14C atoms), alkyl-substituted or unsubstituted alicyclic (14 to 22C atoms), arylaliphatic diamines (C14 to C22) and aliphatic and alicyclic dicarboxylic acids (C6 to C44); the latter may be partially substituted by aromatic dicarboxylic acids. In particular, the transparent polyamide may additionally consist of monomer components having 6C atoms, 11C atoms and/or 12C atoms, which are derived from lactams or ω -aminocarboxylic acids.

Preferably, but not exclusively, the transparent polyamide according to the invention is prepared from the following components: glyceryl trilaurate lactam or omega-aminododecanoic acid, azelaic acid, sebacic acid, n-dodecanedioic acid, fatty acids (C18-C36; for example under the trade name Pripol) Cyclohexane dicarboxylic acids, these aliphatic acids being partially or totally substituted by iso-terephthalic acid, naphthalene dicarboxylic acid, tributyl isophthalic acid. Furthermore, typical representatives of decaalkanediamines, dodecanediamines, nonanediamines, hexamethylenediamine and alkyl-substituted/unsubstituted cycloaliphatic diamines, which are present in unbranched, branched and substituted forms, are bis- (4-aminocyclohexyl) -methane, bis- (3-methyl-4-aminocyclohexyl) -methane, bis- (4-aminocyclohexyl) -propane, bis- (aminocyclohexane), bis- (aminomethyl) -cyclohexane, isophorone diamine or even substituted pentamethyldiamines, can also be used.

Examples of corresponding transparent polyamides are described, for example, in EP 0725100 and EP 0725101.

High-transparency plastic systems based on polymethacrylates, bisphenol-a-polycarbonates, polyamides and cycloolefin copolymers made from norbornene and α -olefins are particularly preferred, which can be produced by means of the nanoscale metal oxides according to the invention into laser-markable or laser-weldable plastic materials without impairing the transparency of the materials.

The high-transparency laser-markable plastic material according to the invention can be provided as a molded body, a semifinished product, a molding compound or a lacquer. The high-transparency laser-weldable plastic material according to the invention is usually provided as a molded body or semi-finished product.

The preparation of the laser-markable and/or laser-weldable plastic materials of high transparency according to the invention is carried out in a manner known per se in accordance with the processes and methods in the manufacture and processing of current plastic materials. The laser-sensitive additives can be introduced into the individual reactants or reaction mixtures before or during the polymerization or polycondensation or they can also be added during the reaction, using the specific manufacturing processes for the corresponding plastic materials known to the person skilled in the art. In the case of polycondensates, such as polyamides, it is possible, for example, to mix additives into one of the monomers of the monomer component. This monomer component can then be subjected to polycondensation in the usual manner together with the remaining reactants. Furthermore, after the formation of the macromolecules, the resulting high molecular weight intermediate or end products can also be mixed with laser-sensitive additives, in which case all methods known to the person skilled in the art can likewise be used.

In the customary apparatus and devices for this purpose, such as reactors, stirred tanks, mixers, roll mills, extruders and the like, fluid, semifluid and solid formulation components or monomers and, if necessary, additives, such as polymerization initiators, stabilizers (e.g.UV absorbers, heat stabilizers), visual brighteners, antistatics, softeners, mold release agents, lubricants, dispersants, antistatics, including also fillers and reinforcing agents or impact modifiers, are mixed and homogenized, if appropriate shaped, and then cured, depending on the compounding composition of the plastic base material. For this purpose, nanoscale laser-sensitive metal oxides are added to the material at appropriate times and mixed homogeneously. The mixing of the laser-sensitive metal oxide on a nanoscale with the same or compatible plastic material in the form of a concentrated premix (masterbatch) is particularly preferred.

It is preferred if the mixing of the laser-sensitive metal oxide of nanometric dimensions into the plastic matrix is carried out under high shear in the plastic matrix. This can be done by appropriate setting of the stirrer, roll mill and extruder. In this way, any possible nano-scale metal oxides can be effectively prevented from agglomerating or aggregating into larger chunks; all large particles present were broken up. The corresponding process and specific process parameters to be selected are well known to those skilled in the art.

The plastic mouldings and semifinished products can be obtained from the monomers and/or prepolymers by injection moulding or extrusion from moulding compounds or by casting processes.

The polymerization can be carried out by methods known to the person skilled in the art, for example by adding one or more polymerization initiators and initiating the polymerization by heating or radiation. In order to obtain complete conversion of the monomers, the polymerization may be followed by a tempering step.

Laser-markable and laser-weldable lacquers are obtained by dispersing nanoscale laser-sensitive oxides in customary lacquer formulations, brushing and drying or hardening the lacquer layer.

Suitable paint sets include, for example, powder paints, physically drying paints, radiation-curable paints, one-component or multi-component reaction paints such as two-component polyurethane paints.

After plastic moldings or lacquers are produced from plastic materials containing laser-sensitive metal oxides on a nanoscale, they can be marked or welded by irradiation using a laser.

Laser marking can be performed on commercially available laser marking equipment, such as StarMark SMM65 type lasers manufactured by Baasel with an average laser output of 65W and recording speeds of 1-200 mm/s. The molded body to be inscribed is inserted into the apparatus and written on a colourless side in white to dark grey with a clear outline and good readability, the radiation resulting in a transparent substrate. In one embodiment, it may also be preferable to focus the laser beam over the substrate. Most pigment particles are excited and strengthened in such a way that a high contrast inscription imprint can be obtained even at low pigment concentrations. The required energy corresponding to the writing speed is a function of the composition and amount of the laser sensitive oxide used. The higher the oxide content, the lower the energy required corresponding to a higher maximum writing speed of the laser beam. The settings necessary in the individual case can also be determined without any further influence.

Laser welding can be performed on commercially available laser marking equipment, such as StarMarkSMM65 type lasers manufactured by Baasel with 0.1-22 Amp output and 1-100 mm/s advance speed. When setting the laser energy and the forward speed, it should be ensured that the output is not chosen too high and the forward speed is not chosen too low in order to avoid undesirable carbonization. At too low an output and too high an advancing speed, welding may be insufficient. The settings necessary in individual cases can also be determined for this purpose without any further influence.

For welding plastic molded bodies or plastic semi-finished products, it is necessary that at least one of the parts to be joined comprises a plastic material according to the invention at least in the surface region, the joining surface being irradiated with a laser that is sensitive to the metal oxides contained in the plastic material. This method is suitably carried out so that the connecting portion facing the laser beam does not absorb the laser energy, and the second connecting portion is made of a plastic material according to the invention, which portion is strongly thermalized at the phase boundary so that the two portions are welded to each other. A certain contact pressure is necessary to obtain the bonding of the materials.

The use of the high-transparency laser-sensitive plastic materials according to the invention for producing laser-markable production products is particularly preferred. The identification of the manufactured products made of these plastic materials is carried out by irradiating them with a laser sensitive to the metal oxides contained in the plastic materials.

Detailed Description

Comparative example a:

trogamid, a commercial product of Marl, a high-performance polymer division of Degussa AGCX7323 as a plastic molding compound. Iriodin from Merck KgaA at a concentration of 0.2% by weight Darmstadt was usedLS800 as a laser sensitive pigment.

The light transmittance in the visible light range was 80%, and the haze was 5%.

Comparative example B:

commercial product Plexiglas from Degussa AG methacrylate department Darmstadt7N were compounded and pelletized at 240 ℃ in a Storck 35 type extruder with a degassing zone. Iriodin from Merck KgaA at a concentration of 0.2% by weight Darmstadt was usedLS800 as a laser sensitive pigment.

The light transmittance in the visible light range was 85%, and the haze was 4%.

Example 1:

preparation of high-transparency laser-sensitive plastic mouldings

A plastic molding compound comprising a laser-sensitive nanoscale pigment is melted in an extruder and injected into an injection mold to form a plastic molded body in the form of a sheet or extruded to form a flat plate, film or tube.

The mixing of the laser-sensitive pigment into the plastic molding compound is carried out under strong shear in order to break up the agglomerated particles that may be present into primary particles of nanometric dimensions.

Embodiment A)

Trogamid, a commercial product of Marl, a high-performance polymer division of Degussa AGCX7323 as a plastic molding compound. A nanoscale indium-tin oxide Nano manufactured by Nanogate was used at a concentration of 0.01 wt%ITO IT-05C 5000 is used as a laser sensitive pigment. The light transmittance in the visible light range was 90%, and the haze was 1.5%.

Embodiment B)

The commercial product Plexiglas from the methacrylate division Darmstadt of the Degussa AG company was used7N as a plastic molding compound. A nanoscale indium-tin oxide Nano manufactured by Nanogate was used at a concentration of 0.001 wt%ITO IT-05C 5000 is used as a laser sensitive pigment. In the case of extrusion, preference may also be given to using PlexiglasHigh molecular weight molding compounds of the 7H type. The light transmission in the visible range was 92% and the haze < 1%.

Example 2:

reduction of highly transparent laser-sensitive plastic molding compounds

Embodiment A)

Trogamid, a commercial product of Marl, a high-performance polymer division of Degussa AGCX7323 as a plastic molding compound with nanoscale indium-tin oxide Nano as a laser-sensitive pigment produced by Nanogate corporation at a concentration of 0.01 wt%ITO IT-05C 5000 was compounded and pelletized at 300 ℃ in a Berstorff ZE 2533D extruder. The light transmittance in the visible light range was 90%, and the haze was 1.5%.

Embodiment B)

Commercial product Plexiglas from Degussa AG methacrylate department DarmstadtNanoscale indium-tin oxide Nano, produced by Nanogate, 7N and 0.001% strength by weight, as laser-sensitive pigmentsCompounding ITO IT-05C 5000 in a Storck 35 type extruder with degassing zone at 240 deg.CAnd (6) granulating. The light transmission in the visible range was 92% and the haze < 1%.

Example 3:

preparation of high-transparency laser-sensitive lacquers and lacquers

Embodiment A)

A nano-sized indium-tin oxide VPAdNano produced by Degussa, 40 parts by weight of pentaerythritol triacrylate, 60 parts by weight of hexane diol diacrylate, and 100 parts by weight ofRadiation-curable acrylate lacquer from ITO R50 and 200 parts by weight of ethanol were dispersed in a glass container on a roller bench for 66 hours while adding glass spheres of 1mm diameter, after which 2 parts of photoinitiator kgacure were mixed184 and is applied to a flat sheet of plastic material by knife coating with a doctor blade made of metal wire. Curing was carried out after a brief ventilation time by irradiation using a commercially available Fusion F400 UV dryer at an advancing speed of 1m/min under an inert gas blanket. The light transmission in the visible range was 90% and the haze < 2%.

Embodiment B)

By placing 100 parts by weight of nanoscale indium-tin oxide VP AdNano produced by Degussa in a glass container on a roll tableITO R50, 100 parts by weight of polymethacrylate (Degalan)742) And 200 parts by weight of butyl acetate were dispersed for 66 hours while adding 1mm diameter glass spheres to prepare a physically drying paint. By using 24 μm wireThe resulting blade was drawn down and the paint was dried at room temperature to effect coating.

The light transmission in the visible range was 90% and the haze < 2%.

Example 4:

implementing laser marking

(cast PMMA with 0.01% by weight ITO content)

A high transparency laser-sensitive plastic plate (size 100mm x 60mm x 2mm) made of cast PMMA with 0.01 wt% ITO content was inserted into the Starmark laser SMM65 tool manufactured by Baasel-Lasertechnik. Ensuring that the plate is maintained at a distance of at least 10mm from the underlying support surface of the tool. The focal point of the laser beam is set in the middle of the thickness of the plate. The laser control unit is provided with a frequency (2250Hz), a lamp current (21.0A) and a writing speed (100 mms)^-1) The parameter (c) of (c). After the desired inscription is entered, the laser is activated. At the end of the writing process, the plastic plate may be removed from the device.

The contrast was rated as 4.

The contrast was determined using the following qualitative method:

contrast level 0: no scribing is possible.

Contrast rating 1: discoloration of the surface of the plastic material was observed and no characters could be read.

Contrast rating 2: the inscription is well readable.

Contrast rating 3: inscriptions and inscriptions in bold of Arial 18 are well readable.

Contrast rating 4: inscriptions, the inscriptions in bold with Arial 18 and the inscriptions with Arial 12 are well readable.

Example 5:

implementing laser marking

(cast PMMA with 0.0001% by weight ITO content)

A high transparency laser sensitive plastic plate (size 100mm x 60mm x 2mm) made of cast PMMA with 0.0001 wt% ITO content was inserted into the Starmark laser SMM65 tool manufactured by Baasel-Lasertechnik. Ensuring that the plate is maintained at a distance of at least 10mm from the underlying support surface of the tool. The focal point of the laser beam was set 20mm above the middle of the plate thickness. The frequency (2250Hz), lamp current (22.0A) and writing speed (10 mms) are set on the control unit of the laser^-1) The parameter (c) of (c). After the desired inscription is entered, the laser is activated. At the end of the writing process, the plastic plate may be removed from the device.

The contrast was rated as 4.

Example 6:

implementing laser marking

(cast PMMA coated with PMMA lacquer containing 0.001 wt.% ITO)

A high transparency laser-sensitive plastic plate (size 100mm 60mm 2mm) made of cast PMMA containing 0.001 wt% ITO, coated on both sides with PMMA lacquer, was inserted into the Starmark laser SMM65 tool produced by Baasel-Lasertechnik. Ensuring that the plate is maintained at a distance of at least 10mm from the underlying support surface of the tool. The focal point of the laser beam was set 20mm above the middle of the plate thickness. The laser control unit is provided with a frequency (2250Hz), a lamp current (21.0A) and a writing speed (15 mms)^-1) The parameter (c) of (c). After the desired inscription is entered, the laser is activated. At the end of the writing process, the plastic plate may be removed from the device.

The contrast was rated as 4.

Example 7:

implementing laser marking

(PA 12 with 0.1% by weight ITO content)

A high transparency laser sensitive standard injection molded plastic plate (size 60mm by 2mm) made from PA12 with 0.1 wt% ITO content was inserted into the Starmark laser SMM65 tool manufactured by Baasel-Lasertechnik. Ensuring that the plate is maintained at a distance of at least 10mm from the underlying support surface of the tool. The focal point of the laser beam is set in the middle of the thickness of the plate. The frequency (2250Hz), lamp current (20.0A) and writing speed (50 mms) are set on the control unit of the laser^-1) The parameter (c) of (c). After the desired inscription is entered, the laser is activated. At the end of the writing process, the plastic plate may be removed from the device.

The contrast was rated as 4.

Example 8:

implementing laser marking

(PA 12 with 0.01% by weight ITO content)

A high transparency laser sensitive standard injection molded plastic plate (size 60mm by 2mm) made from PA12 with 0.01 wt% ITO content was inserted into the Starmark laser SMM65 tool manufactured by Baasel-Lasertechnik. Ensuring that the plate is maintained at a distance of at least 10mm from the underlying support surface of the tool. The focal point of the laser beam is set in the middle of the thickness of the plate. The frequency (2250Hz), lamp current (20.0A) and writing speed (50 mms) are set on the control unit of the laser^-1) The parameter (c) of (c). After the desired inscription is entered, the laser is activated. At the end of the writing process, the plastic plate may be removed from the device.

The contrast was rated as 4.

Example 9:

carrying out laser welding

(cast PMMA with 0.01% by weight ITO content)

A high-transparency laser-sensitive plastic plate (size 60mm by 2mm) made of cast PMMA with an ITO content of 0.01 wt.% was brought into contact with the surface to be welded of a second plastic plate made of undoped cast PMMA. The plates were inserted into the frit holders of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, in such a way that the undoped plates were placed on top, i.e. the undoped plates were first penetrated by the laser beam. The focal point of the laser beam is set to the contact surface of the two plates. The laser control unit is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (30 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values with 4 ratings were obtained using a hand tear test.

Adhesion was evaluated as follows:

0 had no adhesion.

1 slight adhesion.

2 has some adhesion; the separation is somewhat difficult.

3 good adhesion; separation is only possible in difficult situations and perhaps with the aid of tools.

4 inseparable adhesion; separation is only possible by cohesive failure.

Example 10:

carrying out laser welding

(PA 12 with 0.01% by weight ITO content)

A high-transparency laser-sensitive standard injection made of PA12 with an ITO content of 0.01 wt.%The injection molded plastic panel (size 60mm 2mm) was in contact with the surface to be welded of a second standard injection molded plastic panel (size 60mm 2mm) made of undoped PA 12. The plates were inserted into the frit holders of a Starmark laser SMM65, manufactured by Baasel-Lasertechnik, in such a way that the undoped plates were placed on top, i.e. the undoped plates were first penetrated by the laser beam. The focal point of the laser beam is set to the contact surface of the two plates. The laser control unit is provided with a parameter frequency (2250Hz), a lamp current (22.0A) and a forward speed (10 mms)^-1). At the input the size of the area to be welded (22 x 4 mm)²) After that, the laser is started. At the end of the welding process, the welded plastic panels may be removed from the apparatus.

Adhesion values with 4 ratings were obtained using a hand tear test.

Claims (13)

1. Use of a high transparency plastic material for laser marking and/or laser welding, said high transparency being a transmission of more than 85% and a haze of less than 3% at a material thickness of 2mm, measured according to ASTM D1003, characterized in that: the high-transparency plastic material contains doped indium oxide, doped tin oxide or doped antimony oxide as nano-scale laser-sensitive metal oxide which can be marked by laser and/or welded by laser, the particle size of the contained metal oxide is 5-100 nm, and the content of the metal oxide is 0.0001-0.1 wt% relative to the plastic material.

2. Use according to claim 1, characterized in that: the content of the metal oxide is 0.001 to 0.01 wt% with respect to the plastic material.

3. Use according to claim 1, characterized in that: the plastic material comprises indium-tin oxide or antimony-tin oxide as the nano-scale laser-sensitive metal oxide.

4. Use according to claim 3, characterized in that: the plastic material comprises blue indium-tin oxide as the nanoscale laser-sensitive metal oxide.

5. Use according to claim 1, characterized in that: the plastic matrix is based on poly (meth) acrylates, polyamides, styrene polymers and styrene copolymers, polycarbonates, silicones, polyimides, polysulfones, polyether sulfones, polyketones, polyether ketones, polyphenylene sulfides, polyesters, polyethylene oxides, polyurethanes, polyolefins or fluoropolymers.

6. Use according to claim 1, characterized in that: the plastic material is based on polymethyl methacrylate.

7. Use according to claim 1, characterized in that: the plastic material is based on bisphenol a-polycarbonate.

8. Use according to claim 1, characterized in that: the plastic material is based on polyamide.

9. Use according to claim 1, characterized in that: the plastic material is provided as a molded body, a semi-finished product, a molding compound or a lacquer.

10. Use of a laser-sensitive metal oxide of nanometric dimensions for the preparation of a laser-markable and/or laser-weldable plastic material of high transparency, meaning a transmission of more than 85% and a haze of less than 3%, measured according to ASTM D1003, at a material thickness of 2mm, characterized in that: doped indium oxide, doped tin oxide or doped antimony oxide is used as the laser sensitive metal oxide with the nanometer scale, the particle size of the metal oxide is 5-100 nm, and the content of the metal oxide is 0.0001-0.1 wt% relative to the plastic material.

11. Method for welding plastic mouldings or plastic semifinished products, at least one component to be joined comprising at least in the surface region a plastic material according to one of claims 1 to 9, which contains doped indium oxide, doped tin oxide or doped antimony oxide as a nanoscale, laser-sensitive metal oxide, the metal oxide being contained in a particle size of 5 to 100nm and in a content of 0.0001 to 0.1% by weight, relative to the plastic material, wherein the surface is joined by means of laser radiation which is sensitive to the metal oxide contained in the plastic material.

12. Use of a plastic material according to one of claims 1 to 9, containing doped indium oxide, doped tin oxide or doped antimony oxide as laser-sensitive metal oxide on a nanoscale, the metal oxide having a particle size of 5 to 100nm and the metal oxide being present in an amount of 0.0001 to 0.1% by weight, relative to the plastic material, for the production of laser-markable products.

13. A method for identifying manufactured products made of a plastic material according to one of claims 1 to 9, which contains doped indium oxide, doped tin oxide or doped antimony oxide as laser-sensitive metal oxide on a nanoscale, the metal oxide being contained in a particle size of 5 to 100nm and in a content of 0.0001 to 0.1% by weight relative to the plastic material, wherein these products are irradiated with laser light sensitive to the metal oxide contained in the plastic material.