Process for coating a polymeric component, and polymeric component

Abstract

The invention relates to a method for coating a plastic component (10) comprising the following steps: (A) irradiating at least a partial area (12) of the surface (14) of the plastic component (10) with ultraviolet light (30), wherein the partial area (12) is irradiated with a radiation intensity of at least 20,000 µW / cm² for a duration of at least 5 seconds, and (B) after step A, applying at least one layer (16) of a coating agent (18) to the partial area (12). The invention also relates to a plastic component (10) with a coating (26) produced by such a method.

Description

[0001] The present invention relates to a method for coating a plastic component.

[0002] Methods for coating plastic components - such as plastic bumpers - with a coating agent - such as in particular a paint - are known in numerous variants and are subject to constant optimization processes. See, for example, the methods disclosed in DE 10 2004 060 453 A1, DE 10 2004 060 481 A1 or DE 10 2014 002 438. Furthermore, EP 1 273 357 A1 describes a method for painting composite material components in which the component is first activated by means of UV radiation, then covered with a primer coating with a low content of organic solvent, then exposed to UV radiation for a few seconds and finally at least one layer of paint is applied to the primary coating thus exposed.Furthermore, EP 0 643 997 A1 discloses a method for treating lenses made of a transparent plastic material, wherein the surface of each lens is exposed to ultraviolet radiation prior to the application of a protective layer, and the lenses are made of polycarbonate. WO 2011 / 012294 A1 also discloses a method for producing a multilayer product from a substrate having at least one substrate layer containing a thermoplastic polymer and at least one protective layer obtainable from a coating composition. After application, the coating composition is cured by actinic radiation to form a thermosetting protective layer, and the protective layer(s) are applied inline immediately after the substrate is produced.Further methods for coating plastic components are known, for example, from DE 10 2011 076148 A1, EP 0 447 239 A2, US 5 059 447 A, US 4 018 939 A, EP 0 527 633 A1, EP 0 487 323 A1, US 2007 / 065656 A1, FR 2 121 735 A1 and WO 99 / 29438 A1.

[0003] Especially in the industrial series production of coated plastic components, efforts are made to increase the adhesion of the coating to the respective plastic component. Underlying task

[0004] The invention is therefore based on the object of specifying a method for coating a plastic component with which the adhesion of the coating to the plastic component can be significantly increased compared to known coating methods. Inventive solution

[0005] This object is achieved according to the invention by a method having the features of independent claim 1.

[0006] The method according to the invention for coating a plastic component comprises the following steps: (A) irradiating at least a partial area of ​​the surface of the plastic component with ultraviolet light, wherein the partial area is irradiated with a radiation intensity of at least 20,000 µW / cm 2< (this corresponds to 20,000 times 10 -6< W / cm 2< ) for a duration of at least 5 seconds, and (B) after step A, applying at least one layer of a coating agent to the partial area.

[0007] The method according to the invention is a method for coating at least a partial surface of the surface or the entire surface of the plastic component or the plastic component to be coated.

[0008] In step A, at least a partial area of ​​the surface of the plastic component is irradiated with ultraviolet light, wherein the partial area is irradiated with a radiation intensity of at least 20,000 µW / cm 2 for a duration of at least 5 seconds, or wherein in step A the partial area is irradiated with ultraviolet light with a radiation intensity of at least 20,000 µW / cm 2 for a duration of at least 5 seconds. It is understood that in step A, the partial area or the entire surface is respectively entirely with the ultraviolet light at the intensity and duration specified in step A. Or in other words: The irradiation in step A covers the partial area or the entire surface in its entirety.

[0009] It is understood that the radiation intensity of at least 20,000 µW / cm 2< according to step A is the radiation intensity present at the partial area or at the location(s) of the partial area, which is known to differ from the radiation intensity present at a distance from the partial area when the partial area is irradiated by means of a UV light source spaced from the partial area. The radiation intensity of at least 20,000 µW / cm 2< according to step A of the method according to the invention is therefore the radiation intensity present at the partial area (or radiation intensity present at the location(s) of the partial area), the value of which can be set or provided, for example, by measuring the radiation intensity and / or by calculating the radiation intensity before carrying out the method according to the invention. For example, the radiation intensity present at the location of the partial area orMeasure the radiation intensity present at the locations of the partial area as a function of the device-specific intensity setting of the UV light source spaced from the partial area and / or calculate it from the radiation characteristics of the UV light source used.

[0010] In step A, the entire surface or at least a portion of the surface is irradiated with ultraviolet light at a radiation intensity of at least 20,000 µW / cm² for a duration of at least 5 seconds. It is understood that the irradiation can be carried out successively or all at once at the intensity and duration specified in step A. With successive irradiation, areas or sections which together form the entire partial area can each be irradiated one after the other for a duration of at least 5 seconds, e.g. using a movable industrial robot. Depending on the size of the partial area or the entire surface to be irradiated, it would also be possible, however, to irradiate the partial area or the entire surface entirely with a single irradiation or exposure using a suitable UV light source.to be irradiated with a single irradiation process lasting at least 5 seconds, provided that this single irradiation process covers the entire surface or the entire partial area.

[0011] It has been shown experimentally - in particular by measuring contact angles and the disperse and polar portions of the surface energy calculated therefrom of the partial area irradiated in step A or of the entire surface irradiated in step A (calculated, for example, using the known method of Owens and Wendt) - that the adhesion of the partial area to the coating agent (cf. step B) could be significantly increased as a result of the irradiation with ultraviolet light carried out in step A, which was shown by a significant increase in the polar portion of the surface energy, so that a coating produced according to the method according to the invention has an adhesion to the plastic component which is significantly increased or significantly improved compared to an adhesion achievable with a known coating method.which is significantly increased or improved compared to the adhesion achievable with a known coating process.

[0012] In step B, after step A, at least one layer of a coating agent is applied to the partial area or to the entire partial area or to the entire surface, so that after step A the partial area or the entire surface is completely covered with the layer or the at least one layer. The at least one layer can be applied using conventional methods known to those skilled in the art, in particular, for example, by spraying, pouring or doctor blade coating. The coating agent can in particular be a varnish, for example. Experiments have shown in varnish adhesion tests followed by steam jet tests that the method according to the invention can achieve significantly increased or improved adhesion compared to known solutions, particularly when a varnish is used as the coating agent. This is also demonstrated by the following examples.Steps A and B of the method according to the invention can advantageously be implemented particularly easily and can therefore be advantageously integrated as process steps into an existing series production without great effort.

[0013] Particularly preferably, the partial area or the entire surface of the plastic component can be heated to a temperature of at least 50 degrees Celsius before step A and also after step A and / or during step A, which advantageously increases the positive effect of irradiation with ultraviolet light on adhesion, as has been shown experimentally. The heating can be achieved, for example, by irradiating the partial area or the entire surface of the plastic component with infrared radiation.

[0014] In the method according to the invention, in step B, a first layer of a first coating agent is applied to the partial surface and after step B, the following steps are carried out: (C) irradiating the first layer applied to the partial area in step B with ultraviolet light, wherein the first layer is irradiated with a radiation intensity of at least 20,000 µW / cm 2 for a duration of at least 5 seconds, and (D) after step C, applying a second layer of a second coating agent to the first layer.

[0015] As a result of the positive effect of the irradiation in step A already outlined above, the two layers produced according to the inventive method exhibit high adhesion to the plastic component and to each other. According to the invention, the first and / or the second coating agent is / are preferably a paint that contains acrylate or consists of acrylate. It has been experimentally demonstrated by paint adhesion tests using steam jet tests that, in the inventive method, significantly increased or improved adhesion or adherence can be achieved with a paint that contains acrylate or consists of acrylate compared to known solutions. This is also demonstrated by the following examples.

[0016] It is particularly preferable to perform step B within 2 to 6 minutes after completing step A. However, the positive effects of improving paint adhesion are also observed if there is a period of four weeks between step A and step B.

[0017] It is understood that the first coating agent may be a coating agent that differs from the second coating agent. However, the first coating agent may also be identical to the second coating agent, or the first coating agent may be a coating agent that is identical to the second coating agent.

[0018] Particularly preferably, the ultraviolet light, or the light used in step A to irradiate the partial area or the entire surface, is ultraviolet light generated by a low-pressure mercury lamp. With a low-pressure mercury lamp, the activation or increase of the polar component of the surface energy can be achieved significantly better than with an LED lamp that operates at only one wavelength.

[0019] In particular, the ultraviolet light can also be generated by an ultraviolet light-emitting diode and / or an ultraviolet laser. These UV light sources can achieve advantages in terms of paint adhesion or in terms of increasing the polar component of the surface energy through the specific wavelength, power, distance, and speed.

[0020] In particular, the plastic component can comprise or consist of a thermoplastic material. A thermoplastic material is particularly suitable for injection molding and / or extrusion production of a wide variety of plastic components. It has been shown experimentally, in particular through measurements of contact angles and the resulting calculated disperse and polar components of the surface energy of the partial area irradiated in step A or of the entire surface irradiated in step A (calculated, for example, using the well-known method of Owens and Wendt), that the adhesion of the respective irradiated surface could be significantly increased as a result of the irradiation with ultraviolet light carried out in step A, which was reflected in a significant increase in the polar component of the surface energy.Particularly high adhesion has been observed for a plastic component that comprises or consists of polycarbonate. Therefore, the thermoplastic material that the plastic component can preferably comprise or consist of can particularly preferably be a polycarbonate or a polycarbonate.

[0021] It has also been shown by measurements of contact angles and the disperse and polar components of the surface energy of the partial area irradiated in step A or of the entire surface irradiated in step A calculated therefrom that particularly high adhesion can be achieved with a wavelength of the light used for irradiation in step A in the range of 150 nm (nanometers) to 450 nm (nanometers), which is demonstrated by a corresponding increase in the polar component for this wavelength range. In this respect, the ultraviolet light particularly preferably has a wavelength within a range of 350 nm (nanometers) to 450 nm (nanometers), or in this respect, the ultraviolet light used for irradiation in step A particularly preferably has a wavelength within a range of 350 nm (nanometers) to 420 nm (nanometers). In particular, very high adhesion was achieved in tests with a wavelength of 365 nm (nanometers).

[0022] The plastic component can be any desired plastic component. It can, for example, be a plastic component for a motor vehicle. In particular, the plastic component can be, for example, a bumper for a motor vehicle or a rear spoiler for a motor vehicle. In this respect, the method according to the invention can, in particular, be, for example, a method for coating a bumper for a motor vehicle that consists of a plastic material. In this respect, the method according to the invention can, in particular, also be, for example, a method for coating a rear spoiler for a motor vehicle that consists of a plastic material. The method according to the invention can (more generally) also be, for example, a method for coating a plastic component for a motor vehicle.

[0023] In particular, the plastic component can also be, for example, a spoiler or a radiator grille or a sill for a motor vehicle, wherein the plastic component can particularly preferably also be a bumper for an electric vehicle or a radiator grille replacement for an electric vehicle, so that the method according to the invention can also be used or employed in particular for coating these plastic components listed as examples.

[0024] The invention further relates to a plastic component with a coating produced using the method according to the invention. In such a plastic component, as already explained above, there is a bond between the plastic component and the coating that is significantly increased or significantly improved compared to the bond achievable with a known coating method, or that is significantly increased or significantly improved compared to the bond achievable with a known coating method. Short description of the drawing

[0025] In the following, exemplary embodiments of the invention are explained in more detail with reference to the accompanying drawings. Fig. 1A-1C schematic representations to illustrate a first embodiment of a method according to the invention, Fig. 2A-2F schematic representations to illustrate a second embodiment of a method according to the invention, Fig. 3A-3B disperse and polar components surface energies calculated from contact angle measurements, and Fig. 4 a table in which the results of steam jet testing experiments after temperature cycling tests are summarized.

[0026] The Fig. 1A to 1C The first exemplary embodiment of a method according to the invention for coating a plastic component 10 illustrated in FIG. 1 comprises the following steps A (cf. Fig. 1A ) and B (cf. Fig. 1B ) on: (A) Irradiating a partial area 12 of the surface 14 of a plastic component 10 with ultraviolet light 30, wherein the partial area 12 is irradiated with a radiation intensity of 20,000 µW / cm 2 < to a maximum of 200,000 µW / cm 2 < for a duration of 5 seconds to a maximum of 300 seconds (cf. Fig. 1A ), and (B) after step A, applying a layer 16 of a coating agent 18 to the partial surface 12 (cf. Fig. 1B ).

[0027] The plastic component 10 is a grille replacement component 10 for an electric vehicle, which consists at least partially or entirely of polycarbonate or a blend of polycarbonate and is only illustrated very schematically in the form of a sectional view. To irradiate the plastic component 10 with ultraviolet light at the intensity and duration specified in step A, an ultraviolet light-emitting diode 24, shown only schematically, is used. This ultraviolet light-emitting diode 24 is moved over the partial surface 12 by means of an industrial robot (not shown), so that the entire partial surface 12 is irradiated with the desired intensity and duration. The partial surface 12 of the surface or the entire surface of the plastic component 10 is a surface 12 that, among other things, also comprises or includes the surface of the front side of the plastic component 10, which is visible from outside the motor vehicle when attached to the motor vehicle.The wavelength of the ultraviolet light used is 365 nm (nanometers). It is understood that, as an alternative to the successive irradiation used here—in which areas or sections that together form the entire partial surface 12 are irradiated successively with the specified intensity for a duration of 5 seconds each—the partial surface 12 can be irradiated entirely with a single irradiation or with a single irradiation process lasting 5 seconds using a suitable UV light source.

[0028] The application of the layer 16 of the coating agent 18 to the partial surface 12 is carried out by means of a painting device 28, which is moved over the partial surface 15 by means of an industrial robot (not shown) to apply the layer 16 to the entire partial surface 12. The layer 16, with a thickness of approximately 15 µm, is a paint layer 16 made of acrylate, so that the coating agent 18 is a paint consisting of acrylate.

[0029] The Fig. 1C illustrates the finished coated plastic component 10 after completion of the process according to the invention. The plastic component 10 according to Fig. 1C a plastic component 10 with a coating 26 produced by the method according to the invention described above or the plastic component 10 according to Fig. 1Ca plastic component 10 having a coating 26 produced by the method according to the invention described above.

[0030] The Fig. 2A-2F show schematic representations to illustrate a second embodiment of the method according to the invention. In the second embodiment of the method according to the invention, after step A (cf. Fig. 2A and above, step A identical to step A according to Fig. 1A ) in step B a first layer 16 of a first coating agent 18 is applied to the partial surface 12 (cf. Fig. 2B and above, step B identical to step B according to Fig. 1B ) and after step B, the following steps C and D are carried out: (C) Irradiating the first layer 16 applied to the partial area 12 in step B with ultraviolet light 30, wherein the first layer 16 is irradiated with a radiation intensity of 20,000 µW / cm 2 < to a maximum of 200,000 µW / cm 2 < for a duration of 5 seconds to a maximum of 300 seconds (cf. Fig. 2D ), and (D) after step C, applying a second layer 20 of a second coating agent 22 to the first layer (16) (cf. Fig. 2E ).

[0031] The irradiation in steps A and C is carried out using the same ultraviolet light-emitting diode 24 as in the first exemplary embodiment. The application of the coating agents 18, 22 in steps B and D is also carried out using the same painting device 28 as in the first exemplary embodiment, which is moved over the entire partial area 12 or the entire first layer 16 by means of an industrial robot (not shown) to apply the layers 16 and 20 to the partial area 12 or to the first layer 16. The coating agents 18, 22 of the layers 16, 20 are, as in the first exemplary embodiment, a paint consisting of acrylate, so that the two layers 16, 20 are paint layers made of acrylate. The thickness of the paint layers 16, 20 is approximately 15 µm. The plastic component 10 to be coated according to the second exemplary embodiment of the method according to the invention is the same.the same plastic component 10 as the plastic component 10 to be coated according to the first embodiment.

[0032] The Fig. 2F illustrates the finished coated plastic component 10 present after completion of the second embodiment of the method according to the invention. The plastic component 10 according to Fig. 2F a plastic component 10 with a coating 26 produced with the above-described second embodiment of the method according to the invention or the plastic component 10 according to Fig. 2F a plastic component 10 having a coating 26 which has been produced using the second embodiment of the method according to the invention described above.

[0033] The Fig. 2Cillustrates the state of the plastic component 10 after performing step B and before performing step C. In this state, the plastic component 10 is completely coated with the first layer 16.

[0034] The Fig. 3A and 3B show dispersed fractions in percent (cf. Fig. 3B ) and polar fractions in percent (cf. Fig. 3A ) of the surface energy (unit mN / m), which were calculated from contact angle measurements according to the well-known method of Owens and Wendt. The left bar of the Fig. 3Aillustrates the percentage polar portion of the surface energy of a partial area of ​​a plastic component made of polycarbonate that was not irradiated with ultraviolet light according to step A of the inventive method. The right-hand bar, on the other hand, illustrates the percentage polar portion of the surface energy of this partial area of ​​the plastic component made of polycarbonate that was irradiated with ultraviolet light according to step A of the inventive method. A very large increase in the percentage polar portion can be seen (from 3.43 percent to 13.42 percent). The irradiation correspondingly reduced the disperse portion of the surface tension of this partial area (from 96.57 percent to 86.58 percent - see Fig. 3B , where the left bar illustrates the dispersed percentage without irradiation and the right bar illustrates the dispersed percentage with irradiation according to step A). Fig. 3A and 3Bshow that the adhesion of the partial surface for a coating agent could be significantly increased as a result of the irradiation with ultraviolet light carried out according to step A, which is shown in particular by a significant increase in the polar component of the surface energy, so that a coating produced according to the method according to the invention has an adhesion to a partial surface of the plastic component made of polycarbonate, which is significantly increased or significantly improved compared to an adhesion achievable with a known coating method.

[0035] In particular, it was experimentally demonstrated using steam jet tests following thermal cycling tests that the method according to the invention can significantly increase the adhesion of the coating to the plastic component compared to known coating methods. The steam jet tests following thermal cycling tests, including results, test conditions, test components, test equipment, and procedure, are described below. Parts are by weight.

[0036] Plastic components in the form of plates or plates made of polycarbonate were used as test components, namely a polycarbonate (abbreviation "PC") of the type Makrolon AP 2677, obtained from Covestro AG (hereinafter also referred to as PC-Mak called).

[0037] During the tests, the plastic components made of polycarbonate were coated with the following coating agents: Wörwag adhesion primer slate grey conductive, received from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG Base coat black uni MB 9040, received from BASF Coatings Wörwag high gloss clear coat 11141, received from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG Peter-Lacke iridium silver matt single-coat paint, received from Peter-Lacke GmbH Mankiewicz Ink Jet ink CYCONJET-LED-Ink 680-05, received from Mankiewicz GmbH & Co KG WW unit hardener, received from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG.

[0038] The first five coating agents are raw materials for paints. The last coating agent is an additive or additives.

[0039] The primer and isocyanate were prepared as follows: 100 parts of Wörwag slate grey conductive adhesion primer and 10 parts of WW standard hardener were mixed for 3 minutes shortly before primer application at 600 rpm (revolutions per minute) using a stirring disc known to those skilled in the art.

[0040] The preparation of the clear coat and isocyanate was as follows: 100 parts of high-gloss clear coat 11141 and 35 parts of WW standard hardener were mixed for 3 minutes shortly before application of the clear coat at 600 rpm (revolutions per minute) using a stirring disk known to those skilled in the art.

[0041] The plates or plastic components, or their partial areas or entire surfaces, were irradiated at a distance of 60 mm with a low-pressure mercury lamp at a wavelength of 285 nm for a duration of 5 seconds to a maximum of 300 seconds, resulting in a radiation intensity of 20,000 µW / cm 2 to a maximum of 200,000 µW / cm 2 on the partial area or surface of the respective plate. After this irradiation or activation, the platelets or their partial areas or surfaces were coated with primer, basecoat, and clearcoat in this order (i.e., first coat: primer, second coat: basecoat, third coat: clearcoat) under the following conditions: Primer: Wörwag slate gray conductive primer was sprayed crosswise with a gun to achieve a film thickness of 12 µm. It was dried for 25 minutes at 85 °C, and then the basecoat was applied as required. Basecoat:The basecoat black solid MB 9040 was sprayed crosswise with a gun to achieve a film thickness of 15 µm. It was dried for 20 minutes at 85 °C, and then the high-gloss clear coat was applied. High-gloss clear coat: Wörwag High-Gloss Clear Coat 11141 was sprayed crosswise with the gun to achieve a film thickness of 35 µm. It was dried for 30 minutes at 85 °C. Single-layer paint: The single-coat Peter-Lacke Iridium Silver matte was sprayed crosswise with a gun to achieve a film thickness of 35 µm. It was dried for 30 minutes at 85 °C. Inkjet printing: The Mankiewicz Ink Jet ink CYCONJET-LED-Ink 680-05 was applied to the polycarbonate on the machine at Mankiewicz by FPT Prototyp, depending on the example, using a UV-LED lamp at 395 nm and finally cured with a low-pressure Hg lamp.

[0042] After maturation, technical coating tests were conducted. The coated panels were subjected to the following tests: Steam jet testing (HDW)

[0043] The abbreviation "HDW" is derived from the term "high-pressure water jet." This test, also known as steam jet testing (HDW), is used to test the paint adhesion of topcoated or coated plastic exterior parts and to test for delamination. Implementation:

[0044] A Sample preparation: flat, size > 5 x 13 cm (depending on component and geometry), exceptions possible B Damage: St. Andrew's Cross (based on DIN 55662 1st scratch >12 cm, 2nd scratch >5 cm) C Positioning: rigid, covering a scribe, jet center over intersection of the St. Andrew's cross, positioning of test specimen and steam jet lance were fixed during the entire test D Test:The test specimen was loaded with specified test parameters (volume flow, temperature, jet length and width, DIN 55662). E Evaluation: visual assessment comparing with standard images F Evaluation: Evaluation was carried out by comparison with standard images of DIN 55662, where: characteristic value 0 and 1 = green, characteristic value 2 = yellow, characteristic value 3 to 5 = red.

[0045] Here, the value 0 indicates an excellent value. The value 1 indicates a very good value. The value 2 indicates a good value, and the value 3 indicates a satisfactory value. Test parameters: Test parameters according to DIN 55662 method B

[0046] The device pressure was regulated using a specified nozzle to ensure the specified flow rate was maintained. The test pressure was deliberately omitted, as this is defined by the flow rate and the test nozzle.

[0047] Cutting device: For all materials, use a Sikkens scoring tool with a 1 mm blade. Manufacturers include Erichsen or mtv Messtechnik. Test nozzle:

[0048] Manufacturer: Spraying Systems GmbH Paul-Strähle-Straße 10 73614 Schorndorf Tel. 07181 / 40970 Designation: PowerWashJet Order number: ¼ PMEG-2506 Settling distance: linear, min. 30 cm in front of nozzle Spray pattern: see DIN 55662 Jet force distribution: trapezoidal, no pressure peaks

[0049] The results of the steam jet test after temperature cycling test (HDW after TWT) are shown in the table after Fig. 4 The test duration was 3 cycles. Each cycle consisted of 15 h at 105 °C, 30 min at 23 ± 2 °C; 8 h at -40 °C and 30 min at 23 ± 2 °C, followed by the steam jet test described above. The results of the steam jet test after the thermal cycling test are shown in the table below. Fig. 4It was determined five times, for example, on five plates or five polycarbonate plates.

[0050] The results - see the corresponding parameters in the table after Fig. 4 - show: The inventive irradiation of the partial areas or entire surfaces of the plastic or plastic component, i.e. the plates or flakes made of polycarbonate (PC) with ultraviolet light improves or increases the adhesion or basic adhesion in a coating with three layers - in this case primer (first layer), base coat (second layer) and clear coat or high-gloss clear coat (third layer) - compared to a known conventional painting process in which the three layers are applied without providing an inventive irradiation with ultraviolet light (cf. in the table after Fig. 4Experiments 1 and 2, whereby in the entire table, "PC untreated" refers to an experiment in which no irradiation with ultraviolet light according to the invention took place).

[0051] The inventive irradiation with ultraviolet light also improves the adhesion or primer adhesion of so-called "primerless applications", compared to a known conventional painting process in which two layers or two layers of paint are applied without providing an inventive irradiation with ultraviolet light (cf. in the table after Fig. 4 Experiments 5 and 6). List of reference symbols

[0052] 10Plastic component 12Partial surface 14Surface 16Layer (first) 18Coating agent (first) 20Layer (second) 22Coating agent (second) 24Ultraviolet light-emitting diode 26Coating 28Painting device 30Ultraviolet light

Claims

1. A method for coating a plastic component (10), comprising the following steps: (A) irradiating at least one portion (12) of the surface (14) of the plastic component (10) with ultraviolet light (30), wherein the portion (12) is irradiated with a radiation intensity of at least 20,000 µW / cm2 for a period of at least 5 seconds, and (B) after step A, applying at least one layer (16) of a coating agent (18) to the portion (12), wherein in step B a first layer (16) of a first coating agent (18) is applied to the portion (12), and wherein after step B the following steps are carried out: (C) irradiating the first layer (16) applied to the portion (12) in step B with ultraviolet light (30), wherein the first layer (16) is irradiated with a radiation intensity of at least 20,000 µW / cm2 for a period of at least 5 seconds, and (D) after step C, applying a second layer (20) of a second coating agent (22) to the first layer (16), wherein the first and / or the second coating agent (18, 22) is a lacquer that contains acrylate or consists of acrylate.

2. The method according to claim 1, wherein the ultraviolet light is an ultraviolet light generated by a low-pressure mercury lamp.

3. The method according to claim 1, wherein the ultraviolet light is an ultraviolet light generated by an ultraviolet light-emitting diode (24) and / or by an ultraviolet laser.

4. The method according to one of the preceding claims, wherein the plastic component (10) contains a thermoplastic material or consists of a thermoplastic material.

5. The method according to claim 4, wherein the thermoplastic material is a polycarbonate.

6. The method according to one of the preceding claims, wherein the ultraviolet light (30) has a wavelength within a range from 150 nm (nanometres) to 450 nm (nanometres).

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