EP3825014A1 - Process for coating a polymeric component, and polymeric component - Google Patents

Abstract

The invention relates to a method for coating a plastic component (10) with the following steps: (A) irradiating at least one partial area (12) of the surface (14) of the plastic component (10) with ultraviolet light (30), the partial area (12) is irradiated with a radiation intensity of at least 20,000 µW / cm ² 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 ( The invention also relates to a plastic component (10) with a coating (26) produced using such a method.

Description

Background of the invention

The present invention relates to a method for coating a plastic component. The invention also relates to a plastic component with a coating produced using such a method.

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, cf. DE 10 2004 060 453 A1 , the DE 10 2004 060 481 A1 or the DE 10 2014 002 438 disclosed method. In particular in the industrial series production of coated plastic components, efforts are also made to increase the adhesion of the coating to the respective plastic component.

Underlying task

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.

Solution according to the invention

According to the invention, this object is achieved with a method having the features of independent claim 1.

1. (A) Bestrahlen wenigstens einer Teilfläche der Oberfläche des Kunststoffbauteils mit ultraviolettem Licht, wobei die Teilfläche mit einer Strahlungsintensität von wenigstens 20000 µW/cm² (dies entspricht also 20000 mal 10^-6 W/cm²) für eine Dauer von wenigstens 5 Sekunden bestrahlt wird bestrahlt wird, und
2. (B) nach Schritt A Aufbringen wenigstens einer Schicht eines Beschichtungsmittels auf die Teilfläche.

The method according to the invention for coating a plastic component has the following steps:

1. (A) Irradiating at least a partial area of the surface of the plastic component with ultraviolet light, the partial area being 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 period of at least 5 seconds is being irradiated, and
2. (B) after step A, applying at least one layer of a coating agent to the partial area.

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

In step A, at least a partial area of the surface of the plastic component is irradiated with ultraviolet light, the partial area being irradiated with a radiation intensity of at least 20,000 μW / cm ² for a duration of at least 5 seconds, or in step A the partial area with ultraviolet light irradiated with a radiation intensity of at least 20,000 μW / cm ² for a duration of at least 5 seconds. It goes without saying that in step A the partial area or the entire surface is in each case completely irradiated with the ultraviolet light in 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.

It goes without saying that the radiation intensity of at least 20,000 μW / cm ² according to step A is the radiation intensity present at the sub-area or at the location or locations of the sub-area which, as is known, deviates from the radiation intensity at the distance to the sub-area is present when the sub-area is irradiated by means of a UV light source spaced apart from the sub-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 sub-area (or radiation intensity present at the location or locations of the sub-area), which is determined, for example, by measuring the radiation intensity and / or can be set or provided according to its values by calculating the radiation intensity before the method according to the invention is carried out. So one could, for example, those at the location of the partial area or at the locations of the partial area Measure the existing radiation intensity 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.

In step A, the entire surface or at least a partial area of the surface is ^{irradiated with the ultraviolet light with a radiation intensity of at least 20,000 μW / cm 2} for a duration of at least 5 seconds. It goes without saying that the irradiation can be carried out successively or all at once with the intensity and duration specified in accordance with step A. In the case of successive irradiation, areas or sections which together form the entire partial area can each be irradiated in succession for a period of at least 5 seconds, for example using a movable industrial robot. Depending on the size of the partial area to be irradiated or the entire surface, however, it would also be possible to completely use the partial area or the entire surface by means of a suitable UV light source with a single irradiation or with a single irradiation process lasting at least 5 seconds continues to irradiate, provided that this single irradiation process covers the entire surface or the entire partial area.

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

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 entirely is covered with the layer or the at least one layer. The at least one layer can be applied by means of customary methods known to the person skilled in the art, in particular, for example, by spraying, pouring or knife-coating. The coating agent can in particular be a lacquer, for example. It has been shown experimentally in paint adhesion tests with subsequent steam jet tests that with the method according to the invention, in particular with a paint as a coating agent, a significantly increased or improved adhesion or adhesion compared to known solutions can be achieved. This is also demonstrated by the following examples. Steps A and B of the method according to the invention can advantageously be implemented in a particularly simple manner and therefore advantageously integrated as process steps into an existing series production without great effort.

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 both after step A and / or during step A, which advantageously enhances the positive effect of the irradiation with the ultraviolet light increased on the liability, as has been shown experimentally. The heating can be carried out, for example, by irradiating the partial area or the entire surface of the plastic component with infrared radiation.

• (C) Bestrahlen der in Schritt B auf die Teilfläche aufgebrachten ersten Schicht mit ultraviolettem Licht, wobei die erste Schicht mit einer Strahlungsintensität von wenigstens 20000 µW/cm² für eine Dauer von wenigstens 5 Sekunden bestrahlt wird, und
• (D) nach Schritt C Aufbringen einer zweiten Schicht eines zweiten Beschichtungsmittels auf die erste Schicht.

In a preferred embodiment of the method according to the invention, a first layer of a first coating agent is applied to the partial area in step B and the following steps are carried out after step B:

• (C) irradiating the first layer applied to the partial area in step B with ultraviolet light, the first layer being ^{irradiated with a radiation intensity of at least 20,000 μW / cm 2} for a period of at least 5 seconds, and
• (D) after step C, applying a second layer of a second coating agent to the first layer.

As a result of the positive effect of the irradiation according to step A already set out above, the two layers produced according to this preferred embodiment of the method according to the invention have a high degree of adhesion to the plastic component and among each other. In this preferred embodiment, the first and / or the second coating agent is / are preferably a lacquer which comprises acrylate or consists of acrylate. It has been shown experimentally by paint adhesion tests with steam jet tests that in this preferred embodiment of the method according to the invention, in particular with a paint that comprises acrylate or consists of acrylate, a significantly increased or improved adhesion or liability can be achieved compared to known solutions. This is also proven the following examples.

Step B is particularly preferably carried out within 2 to 6 minutes after step A has been completed. The positive effects of improving paint adhesion are also found if there is a period of four weeks between step A and step B.

It goes without saying that the first coating agent can be a coating agent that differs from the second coating agent. However, the first coating agent can also be identical to the second coating agent or the first coating agent can be a coating agent identical to the second coating agent.

The ultraviolet light or the light used in step A to irradiate the partial area or the entire surface is particularly preferably an 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 only works with one wavelength.

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

In particular, the plastic component can have a thermoplastic plastic material or consist of a thermoplastic plastic material. A thermoplastic plastic material is particularly suitable for injection molding and / or extrusion production a variety of different plastic components. It has been shown experimentally, in particular through measurements of contact angles and the calculated disperse and polar portion of the surface energy of the partial area irradiated in step A or the entire surface irradiated in step A (calculated e.g. with the known method of Owens and Wendt) that In particular, the adhesion of the respective irradiated surface could be increased significantly as a result of the irradiation with the ultraviolet light carried out according to step A, which was shown by a clear increase in the polar component of the surface energy. A particularly high level of adhesion was found for a plastic component which has polycarbonate or consists of polycarbonate. In this respect, the thermoplastic plastic material, which the plastic component can preferably have or which it can preferably consist of, can particularly preferably be a polycarbonate or a polycarbonate.

It has also been shown by measurements of contact angles and the calculated disperse and polar portion of the surface energy of the partial area irradiated in step A or the entire surface irradiated in step A that with a wavelength of the light used for irradiation in step A in the range from 150 nm (nanometers) to 450 nm (nanometers), a particularly high level of adhesion can be achieved, which was 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 from 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, with a wavelength of 365 nm (nanometers), a very high level of adhesion could be achieved in tests.

The plastic component can be any plastic component. It can be a plastic component for a motor vehicle, for example. 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 which 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 which consists of a plastic material. The inventive method can (more generally) also be a method for coating a plastic component for a motor vehicle, for example.

In particular, the plastic component can also be, for example, a spoiler or a radiator grille or a sill for a motor vehicle, the plastic component particularly preferably also being a bumper for an electric vehicle or a radiator grille replacement for an electric vehicle, so that thus the method according to the invention can in particular also be used or used for coating these plastic components listed by way of example.

The invention also 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 an adhesion between the plastic component and the coating, which is significantly increased or improved compared to an adhesion achievable with a known coating method or the adhesion achievable with a known coating method is significantly increased or is significantly improved.

Brief description of the drawing

Fig.1A- 1C

schematische Darstellungen zur Veranschaulichung eines ersten Ausführungsbeispiels eines erfindungsgemäßen Verfahrens,

Fig. 2A- 2F

schematische Darstellungen zur Veranschaulichung eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Verfahrens,

Fig. 3A-3B

Disperse und polare Anteile aus Kontaktwinkelmessungen berechneten Oberflächenenergien, und

Fig. 4

eine Tabelle, in welcher die Ergebnisse von Versuchen zur Dampfstrahlprüfung nach Temperaturwechseltests zusammengefasst sind.

Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. In the drawing shows

Figures 1A-1C

schematic representations to illustrate a first embodiment of a method according to the invention,

Figures 2A-2F

schematic representations to illustrate a second exemplary embodiment of a method according to the invention,

Figures 3A-3B

Disperse and polar fractions surface energies calculated from contact angle measurements, and

Fig. 4

a table in which the results of experiments on the steam jet test after temperature change tests are summarized.

1. (A) Bestrahlen einer Teilfläche 12 der Oberfläche 14 eines Kunststoffbauteils 10 mit ultraviolettem Licht 30, wobei die Teilfläche 12 mit einer Strahlungsintensität von 20000 µW/cm² bis maximal 200000 µW/cm² für eine Dauer von 5 Sekunden bis maximal 300 Sekunden bestrahlt wird (vgl. Fig. 1A), und
2. (B) nach Schritt A Aufbringen einer Schicht 16 eines Beschichtungsmittels 18 auf die Teilfläche 12 (vgl. Fig. 1B).

That by means of the Figures 1A to 1C The illustrated first exemplary embodiment of a method according to the invention for coating a plastic component 10 has the following steps A (cf. Figure 1A ) and B (cf. Figure 1B ) on:

1. (A) Irradiating a partial area 12 of the surface 14 of a plastic component 10 with ultraviolet light 30, the partial area 12 being 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 (see. Figure 1A ), and
2. (B) after step A, applying a layer 16 of a coating agent 18 to the partial area 12 (cf. Figure 1B ).

The plastic component 10 is a grid replacement component 10 for an electric vehicle, which consists at least partially or entirely of polycarbonate or a blend of the polycarbonate and is illustrated only very schematically in the form of a sectional illustration. To irradiate the plastic component 10 with the ultraviolet light with the intensity and duration specified in step A, an ultraviolet light-emitting diode 24, shown only schematically, is used, which is moved over the partial surface 12 by means of an industrial robot, not shown, so that the entire partial surface 12 with the desired intensity and duration is irradiated. The partial area 12 of the surface or the entire surface of the plastic component 10 is an area 12 which, among other things, also comprises or includes the area of the front side of the plastic component 10, which is visible from outside the motor vehicle when it is attached to the motor vehicle . The wavelength of the ultraviolet light used is 365 nm (nanometers). It goes without saying that the partial area 12 as an alternative to the successive irradiation used here - in which areas or sections that together form the entire partial area 12 are irradiated in succession for a period of 5 seconds with the specified intensity - by means of a suitable UV light source can be completely irradiated with a single irradiation or with a single irradiation process that lasts 5 seconds.

The layer 16 of the coating agent 18 is applied to the partial area 12 by means of a painting device 28, which is moved over the partial area 15 by means of an industrial robot (not shown) to apply or apply the layer 16 to the entire partial area 12. The layer 16 with a thickness of approximately 15 μm is involved is a lacquer layer 16 made of acrylate, so that the coating agent 18 is a lacquer made of acrylate.

The Figure 1C illustrates the fully coated plastic component 10 present after the method according to the invention has been completed. The plastic component 10 is therefore after Figure 1C a plastic component 10 with a coating 26 produced using the above-described method according to the invention, or the plastic component 10 is accordingly Figure 1C a plastic component 10 which has a coating 26 which has been produced using the above-described method according to the invention.

• (C) Bestrahlen der in Schritt B auf die Teilfläche 12 aufgebrachten ersten Schicht 16 mit ultraviolettem Licht 30, wobei die erste Schicht 16 mit einer Strahlungsintensität von 20000 µW/cm² bis maximal 200000 µW/cm²für eine Dauer von 5 Sekunden bis maximal 300 Sekunden bestrahlt wird (vgl. Fig. 2D), und
• (D) nach Schritt C Aufbringen einer zweiten Schicht 20 eines zweiten Beschichtungsmittels 22 auf die erste Schicht (16) (vgl. Fig. 2E).

The Figures 2A-2F show schematic representations to illustrate a second exemplary embodiment of the method according to the invention. In the second embodiment of the method according to the invention, after step A (cf. Figure 2A and above, step A is identical to step A according to FIG Figure 1A ) in step B a first layer 16 of a first coating agent 18 is applied to the partial area 12 (cf. Figure 2B and above, step B is identical to step B according to FIG Figure 1B ) and after step B the following steps C and D are carried out:

• (C) irradiating the first layer 16 applied to the partial surface 12 in step B with ultraviolet light 30, the first layer 16 having 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 Is irradiated for 300 seconds (cf. Figure 2D ), and
• (D) after step C, applying a second layer 20 of a second coating agent 22 to the first layer (16) (cf. Figure 2E ).

The irradiation in steps A and C takes place with the same or 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 also takes place with the same or the same painting device 28 as in the first exemplary embodiment, which is used for applying or applying the layers 16 and 20 to the partial surface 12 or to the first layer 16 is moved over the entire partial area 12 or the entire first layer 16 by means of an industrial robot (not shown). The coating means 18, 22 of the layers 16, 20 are, as in the first exemplary embodiment, a lacquer consisting of acrylate, so that the two layers 16, 20 are lacquer layers made of acrylate. The The thickness of the lacquer 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 or the same plastic component 10 as the plastic component 10 to be coated according to the first exemplary embodiment.

The Figure 2F illustrates the finished coated plastic component 10 present after completion of the second exemplary embodiment of the method according to the invention. The plastic component 10 is therefore after Figure 2F a plastic component 10 with a coating 26 produced with the above-described second exemplary embodiment of the method according to the invention, or the plastic component 10 is therefore in accordance with Figure 2F a plastic component 10 which has a coating 26 which has been produced with the above-described second exemplary embodiment of the method according to the invention.

The Figure 2C also illustrates the state of the plastic component 10 that is present after step B has been carried out and before step C has been carried out. In this state, the plastic component 10 is completely coated with the first layer 16.

The Figures 3A and 3B show disperse fractions in percent (cf. Figure 3B ) and polar proportions in percent (cf. Figure 3A ) the surface energy (unit mN / m) calculated from contact angle measurements using the well-known method of Owens and Wendt. The left bar of the Figure 3A illustrates the percentage polar portion of the surface energy of a partial area of a plastic component made of polycarbonate that was not irradiated with the ultraviolet light in accordance with step A of the method according to the invention. The right 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, which was irradiated with the ultraviolet light according to step A of the method according to the invention. You can see a very high increase in the percentage polar share (from 3.43 percent to 13.42 percent). As a result of the irradiation, the disperse portion of the surface tension of this partial area was correspondingly reduced (from 96.57 percent to 86.58 percent - cf. Figure 3B , there the left bar illustrates the disperse percentage share without irradiation and the right bar illustrates the disperse percentage share with irradiation according to step A). The Figures 3A and 3B show that the adhesion of the partial surface for a coating agent as a result of the irradiation carried out according to step A with the ultraviolet light could be increased significantly, which is particularly evident in a Shows an 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 improved compared to an adhesion achievable with a known coating method.

In particular, it was possible to demonstrate experimentally on the basis of steam jet tests after temperature change tests that the adhesion of the coating to the plastic component can be significantly increased by means of the method according to the invention compared to known coating methods. The steam jet tests after temperature change tests, including results, test conditions, test components, test equipment and implementation, are described below, with parts being understood as parts by weight.

• Wörwag Haftprimer schiefergrau leitfähig, erhalten von KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG
• Basislack Schwarz uni MB 9040, erhalten von BASF Coatings
• Wörwag Hochglanzklarlack 11141, erhalten von KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG
• Peter-Lacke Iridium silber matt Einschichtlack, erhalten von Peter-Lacke GmbH
• Mankiewicz Ink Jet Tinte CYCONJET-LED-Ink 680-05, erhalten von Mankiewicz GmbH & Co KG
• WW Einheitshärter, erhalten von KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG.

Plastic components in the form of plates or platelets made of polycarbonate were used as test components, namely made of a polycarbonate (abbreviation “PC”) of the Makrolon AP 2677 type, obtained from Covestro AG (also referred to as PC-Mak for short in the figure). During the tests, the plastic components made of the polycarbonate were coated with the following coating agents:

• Wörwag adhesive primer slate gray conductive, obtained from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG
• Basecoat black uni MB 9040, obtained from BASF Coatings
• Wörwag high-gloss clear lacquer 11141, obtained from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG
• Peter-Lacke Iridium silver matt single-layer paint, obtained from Peter-Lacke GmbH
• Mankiewicz Ink Jet Ink CYCONJET-LED-Ink 680-05, obtained from Mankiewicz GmbH & Co KG
• WW standard hardener, obtained from KARL WÖRWAG Lack- und Farbenfabrik GmbH & Co KG.

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

The primer and isocyanate were prepared as follows:
100 parts of Wörwag adhesive primer, slate gray conductive, and 10 parts of WW standard hardener were mixed for 3 minutes just before the primer was applied at 600 rpm (revolutions per minute) and a stirring disk known to the person skilled in the art.

The preparation of the clear lacquer and the isocyanate was carried out as follows:
100 parts of high-gloss clearcoat 11141 and 35 parts of WW standard hardener were mixed for 3 minutes at 600 rpm (revolutions per minute) and a stirring disk known to the person skilled in the art shortly before the clearcoat was applied.

• Primer: Wörwag Haftprimer schiefergrau leitfähig wurde im Kreuzgang mit einer Pistole so gespritzt, dass eine Schichtdicke von 12 µm erreicht wurde. Es wurde für 25 min bei 85 °C getrocknet und dann wurde in Abhängigkeit der Beispiele der Basislack aufgetragen.
• Basislack: Basislack schwarz uni MB 9040 wurde im Kreuzgang mit einer Pistole so gespritzt, dass die Schichtdicke von 15 µm erreicht wurde. Es wurde für 20 min bei 85 °C getrocknet und dann wurde der Hochglanzklarlack aufgetragen.
• Hochglanzklarlack: Wörwag Hochglanzklarlack 11141 wurde im Kreuzgang mit der Pistole so gespritzt, dass die Schichtdicke von 35 µm erreicht wurde. Es wurde für 30 min bei 85 °C getrocknet.
• Einschichtlack: Einschichtlack Peter-Lacke Iridium silber matt wurde im Kreuzgang mit der Pistole so gespritzt, dass die Schichtdicke von 35 µm erreicht wurde. Es wurde für 30 min bei 85 °C getrocknet.
• Inkjet Druck: Die Mankiewicz Ink Jet Tinte CYCONJET-LED-Ink 680-05 wurde auf der Maschine bei Mankiewicz von FPT Prototyp je nach Beispiel auf das Poylcarbonat aufgebracht mittels einer UV-LED Lampe bei 395 nm gepinnt und mit einer Hg-Niederdrucklampe endgehärtet.

The platelets or plastic components or their partial area or entire surface were irradiated at a distance of 60 mm with an Hg low-pressure lamp at a wavelength of 285 nm for a duration of 5 seconds to a maximum of 300 seconds, so that on the partial area or surface the respective platelet had a radiation intensity of 20,000 µW / cm ² to a maximum of 200,000 µW / cm ² . After this irradiation or activation, the platelets or their partial areas or surfaces, depending on the examples, were coated with primer, basecoat and clearcoat in this order (i.e. first layer: primer, second layer: basecoat, third layer: clearcoat) under the following conditions :

• Primer: Wörwag adhesive primer slate gray conductive was sprayed crosswise with a gun so that a layer thickness of 12 µm was achieved. It was dried for 25 min at 85 ° C. and then, depending on the examples, the basecoat was applied.
• Basecoat: Basecoat black uni MB 9040 was sprayed crosswise with a gun so that a layer thickness of 15 µm was achieved. It was dried for 20 min at 85 ° C. and then the high-gloss clear lacquer was applied.
• High-gloss clear lacquer: Wörwag high-gloss clear lacquer 11141 was sprayed crosswise with the gun so that a layer thickness of 35 µm was achieved. It was dried at 85 ° C. for 30 min.
• Single- layer paint: Peter-Lacke Iridium silver matt single-layer paint was sprayed crosswise with the gun so that a layer thickness of 35 µm was achieved. It was dried at 85 ° C. for 30 min.
• Inkjet printing: The Mankiewicz Ink Jet Ink CYCONJET-LED-Ink 680-05 was applied to the carbonate on the machine at Mankiewicz from FPT Prototyp using a UV-LED lamp at 395 nm and finally cured with a Hg low-pressure lamp.

Technical paint tests were carried out after maturation. The coated panels were therefore subjected to the following tests:

Steam jet test (HDW)

The abbreviation "HDW" is derived from the term "high pressure water jet". This test, i.e. the steam jet test (HDW), is used to test the paint adhesion of top-coated or coated external plastic parts and to test for delamination.

• A Probenvorbereitung: plan, Größe > 5 x 13 cm (bauteil- und geometrieabhängig), Ausnahmen möglich
• B Beschädigung: Andreaskreuz (in Anlehnung an DIN 55662 1. Ritz >12 cm, 2. Ritz >5 cm)
• C Positionierung: starr, deckend über einen Ritz, Strahlzentrum über Schnittpunkt des Andreaskreuz, Positionierung Probekörper und Dampfstrahllanze wurden während gesamter Prüfung fixiert
• D Prüfung: Probekörper wurde mit vorgegebenen Prüfparametern (Volumenstrom, Temperatur, Strahllänge und -breite, DIN 55662) belastet.
• E Auswertung: visuelle Begutachtung unter Vergleich mit Standardbildern
• F Bewertung: Auswertung erfolgte mittels Vergleich mit Standardbildern der DIN 55662, dabei ist:
  • Kennwert 0 und 1 = grün,
  • Kennwert 2 = gelb,
  • Kennwert 3 bis 5 = rot.

Execution:

• 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 over a scratch, the center of the beam over the intersection of the St. Andrew's cross, positioning of the specimen and the steam jet lance were fixed during the entire test
• D Test : The test specimen was loaded with specified test parameters (volume flow, temperature, beam length and width, DIN 55662).
• E Evaluation: visual assessment and comparison 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.

Here, the characteristic value 0 indicates an excellent value. The parameter 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

The device pressure was regulated with a prescribed nozzle so that the specified volume flow was maintained. The test pressure was deliberately omitted because it is defined by the volume flow and the test nozzle.

Cutter: For all materials Sikkens scribe, blade 1 mm. Possible manufacturers Erichsen or mtv Messtechnik.

Test nozzle:

Manufacturer: Spraying Systems GmbH
Paul-Straehle-Strasse 10
73614 Schorndorf
Tel. 07181/40970
Name: PowerWashJet
Order number: ¼ PMEG-2506
Calming section: linear, at least 30 cm in front of the nozzle
Jet pattern: see DIN 55662
Radiation force distribution: trapezoidal, no pressure peaks

The results of the steam jet test after temperature change test (HDW according to TWT) are shown in the table below Fig. 4 summarized. The test duration was 3 cycles. Every 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 temperature cycle test are shown in the table below Fig. 4 summarized. It was determined five times, for example on five plates or on five small plates made of the polycarbonate.

The results - see the corresponding characteristic values in the table Fig. 4 - show: The inventive irradiation of the partial areas or entire surfaces of the plastic or plastic component, ie the plates or platelets made of the polycarbonate (PC) with the ultraviolet light improves or increases the adhesion or the basic adhesion in a coating with three layers - in this case primer (first layer), basecoat (second layer) and clearcoat or high-gloss clearcoat (third layer) - compared to a known conventional painting process in which the three layers are applied without irradiation according to the invention with ultraviolet light (cf. . in the table according to Fig. 4 Experiments 1 and 2, where in the entire table under "PC untreated" is to be understood in each case an experiment in which there was no inventive irradiation with ultraviolet light).

The inventive irradiation with ultraviolet light also improves the adhesion or basic 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 inventive irradiation with ultraviolet light to be provided (cf. in the table after Fig. 4 experiments 5 and 6).

List of reference symbols

10

Plastic component

12th

Partial area

14th

surface

16

Shift (first)

18th

Coating agent (first)

20th

Shift (second)

22nd

Coating agent (second)

24

Ultraviolet light emitting diode

26th

Coating

28

Painting facility

30th

Ultraviolet light

Claims (9)

Method for coating a plastic component (10) with the following steps: (A) irradiating at least one partial area (12) of the surface (14) of the plastic component (10) with ultraviolet light (30), the partial area (12) with a radiation intensity of at least 20,000 µW / cm ² for a period of at least 5 seconds is irradiated, and (B) after step A, applying at least one layer (16) of a coating agent (18) to the partial area (12). Method according to claim 1, wherein in step B a first layer (16) of a first coating agent (18) is applied to the partial area (12) and wherein after step B the following steps are carried out: (C) irradiating the first layer (16) applied to the partial surface (12) in step B with ultraviolet light (30), the first layer (16) having a radiation intensity of at least 20,000 μW / cm ² for a duration of at least 5 Seconds is irradiated, and (D) after step C, applying a second layer (20) of a second coating agent (22) to the first layer (16). Method according to claim 2, wherein the first and / or the second coating agent (18, 22) is a lacquer which comprises acrylate or consists of acrylate. A method according to any one of the preceding claims, wherein the ultraviolet light is ultraviolet light generated by a low pressure mercury lamp. A method according to any one of claims 1 to 3, wherein the ultraviolet light is an ultraviolet light generated by an ultraviolet light-emitting diode (24) and / or an ultraviolet light generated by an ultraviolet laser. Method according to one of the preceding claims, wherein the plastic component (10) has a thermoplastic plastic material or consists of a thermoplastic plastic material. The method of claim 6, wherein the thermoplastic plastics material is a polycarbonate. A method according to any one of the preceding claims, wherein the ultraviolet light (30) has a wavelength within a range of 150 nm (nanometers) to 450 nm (nanometers). Plastic component (10) with a coating (26) produced by a method according to one of Claims 1 to 8.

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