WO2006066719A2

WO2006066719A2 - Moulded plastic part and method for producing said part

Info

Publication number: WO2006066719A2
Application number: PCT/EP2005/012965
Authority: WO
Inventors: Gunther Ellenrieder; Arnulf Frisch; Reiner Jocher; Peter Lehmann; Klaus-Erik Schmid
Original assignee: Daimlerchrysler Ag
Priority date: 2004-12-17
Filing date: 2005-12-03
Publication date: 2006-06-29
Also published as: DE102004060810A1; WO2006066719A3

Abstract

The invention relates to a method for producing a moulded plastic part from a transparent plastic film material. According to said method, the film material is printed on one side by means of a printing method, is shaped by deep-drawing and after said shaping process is back injection moulded from the printed side with a transparent plastic. The aim of the invention is to improve a method of this type. To achieve this, the film material is provided with a scratch-resistant layer on the opposite side of the film material from the printing. The invention also relates to a moulded plastic part that has been produced by said method.

Description

Plastic molding and method for its production

The invention relates to a method for producing a plastic molding according to the preamble of patent claim 1 and a plastic molding produced by this method according to the preamble of patent claim 9.

For many industrial applications plastic moldings are used with different colored and / or transparent areas. This poses the problem of producing areas of different coloration and transparency within a molding.

From the generic DE 38 40 542 Cl a method for producing such a molded part is known. There, a film material made of plastic is provided with a color imprint, isostatically formed by means of a pressurized fluid into the shape of the later molded part and injected behind in an injection mold with thermoplastic material.

However, this method is only applicable for molded parts that are exposed to little or no environmental impact. Environmental influences in the form of scratches, blows, UV radiation or shocks, for example, play a role Plastic parts that are to be used on the outer skin of the body of a motor vehicle, a major role.

The invention has for its object to propose a plastic molding and a method for producing the molding, which has a high resistance to external influences in a simple and production-compatible production.

The object is achieved by the features of claims 1 and 9.

Thereafter, a plastic film material is printed on one side by means of a printing process for producing a plastic molding and provided on its side facing away from the printed side with a scratch-resistant layer. Furthermore, the film material is formed by a deep-drawing process and back-molded after forming from the printed side with a transparent plastic.

Thus, a robust plastic molded part can be produced in one step, which on the one hand in terms of decor, color and translucency is freely designable and on the other hand by the scratch-resistant coating has a high protection against shocks, shocks, UV radiation and scratches.

Advantageously, the film material is printed by means of a screen printing process. This is a proven and widely used industrial process. Furthermore, it offers in comparison to other printing processes a thick paint application (claim 2). Alternatively, the film material can be printed by means of an inkjet printing process. The ink-jet printing method offers the advantage over the screen printing method that all the colors can be applied in one process step, which eliminates the problem of exact positioning of the printed copies to the film (claim 3).

In an advantageous embodiment of the invention, an electrically conductive material is used as the color layer. In this case, the color layer of electrically conductive material on the one hand serve as an integrated into the plastic molding antenna. On the other hand, the color layer of electrically conductive material can serve as a heating element integrated into the plastic molded part. In this way, the number of components used in the motor vehicle by the integration of as many different functions and items in a single, easy to manufacture component can be reduced (claims 4 to 6).

Advantageously, the scratch-resistant layer is produced by spraying a Siloxanlackes on the film material. Thus, the scratch-resistant layer can be applied in a very simple manner (claim 7).

In an alternative advantageous embodiment, the scratch-resistant layer is produced together with the film material by coextrusion. In this way, the scratch-resistant plastic layer is firmly connected to the film material from the beginning of the process. Furthermore, as a scratch-resistant layer of constant thickness can be achieved (claim 8).

Furthermore, a plastic molded part produced by the method is proposed. The molded part comprises a plastic Film, a back-injected layer of transparent plastic, as well as a color layer between plastic film and back-injected plastic layer. Furthermore, the plastic molded part comprises a layer of a scratch-resistant plastic which adjoins the side of the film opposite the ink layer. In this way, a plastic molding with high impact, impact and scratch resistance can be made without additional measures, which combines both transparent and non-transparent areas with or without decor in a component without joints. As a result, a summary of individual components in a component with an associated cost savings is achieved (claim 9).

Advantageously, the material for the film material is polycarbonate. It is a high quality plastic with good use and processing properties (claim 10).

Also advantageous is the use of polymethyl methacrylate (PMMA) as a scratch-resistant plastic. It is a material with extremely high impact resistance, which allows the use of the plastic molding, for example as a light cover, disc or roof element. (Claim 11).

Further embodiments and advantages of the invention will become apparent from the remaining dependent claims and the description.

In the drawings, the invention is explained in more detail with reference to several embodiments. Show it :

Fig. 1 shows an embodiment of a plastic molding as a bumper with integrated light, Fig. FIG. 2 is a sectional view through the bumper of FIG.

1, Fig. 3 shows another embodiment as a printed

Roof element and Fig. 4 is a detail view of the roof element according to FIG. Third

Fig. 1 shows an exemplary embodiment of a plastic molded part 1. This is a bumper 3 for a motor vehicle with rear lights 5 integrated therein. A functional area 7 of the bumper 3 has a specific coloration, for example the vehicle color, while for the rear lights 5 a red color Outside area 9 and a round transparent inner area 11 is provided.

Fig. 2 shows a detailed view of this plastic molding 1. As can be seen, the molding 1 consists of four layers arranged on top of each other. These layers and their production will now be described in detail by means of an exemplary method for producing the plastic molded part 1.

In order to produce the plastic molding 1, a transparent film 13 made of a plastic is used as the basis. This film 13 consists of a thermoplastic, thermoformable plastic. For example, a transparent film material 14 based on polycarbonate, PMMA, PET (polyester tartrate), SAN (styrene-acrylonitrile copolymer) or PS (polystyrene), also in combination with suitable blend materials, has proved to be suitable. Also suitable, however, are, for example, polyesters, polyamides or polyimides or mixtures of these plastics in different compositions. This film 13 is first of the one side, hereinafter referred to as the printing side 15 is provided with a color layer 17 by a printing process.

The different colors of the bumper 3 described above can be realized by a color layer 17, which accordingly consists of an opaque dye for the functional area 7 and a transparent red or orange dye for the outdoor area 9.

As a method for applying the color layer 17, a screen printing method can be used. By a screen printing method, a relatively thick ink layer 17 can be applied. Alternatively, the ink layer 17 may be applied by an ink jet printing method. This offers the advantage that all required colors can be applied in one step by means of a print head, so that the print templates do not have to be repeatedly positioned with high precision during the printing process.

In the next step, the printed film 13 is brought into the shape corresponding to that of the subsequent molded part 1. This is done by a deep drawing process. In the method used here, the film 13 is drawn by heat and negative pressure in the form of a vacuum in a thermoforming mold, on whose wall it fits tightly.

In the following method step, a further plastic layer 25 of transparent plastic is sprayed onto the printed printing side 15 of the deformed film 13, on which the ink layer 17 is located, by an injection molding process. This plastic layer 25 is significantly thicker than the film 13 and serves to provide the plastic molded part 1 with a dimensional stability. The back-injected Plastic layer 25 consists in this embodiment of the same plastic material as the film 13, but it can also consist of another transparent, suitable for injection molding plastic. It would be conceivable in particular polyester, PC, PMMA, PS, ABS resin or polyfluorohydrocarbons.

In the next step, the film 13 of the side facing away from the color layer 17 outside 19 with a scratch-resistant layer 21 of a further transparent plastic, the z. B. Ensures scratch and UV resistance. As a material for this example Polymehtylmethacrylat

(PMMA), which is characterized by a high impact resistance and scratch resistance. This scratch-resistant layer 21 will lie in the later plastic molded part 1 on the outside facing the environment 23 of the plastic molded part 1. The scratch-resistant layer 21 is applied to the outside 19 of the film 13 by spraying a siloxane paint on the back of the printed film. As an alternative to spraying, the scratch-resistant layer 21 may also be formed by a dipping method, a plasma coating, a PVD

(Physical Vapor Deposition) - or a CVD (Chemical Vapor Deposition) - coating are applied.

Thus, optionally, the entire bumper 3 can be provided on the outside 23 with a scratch-resistant layer 21 or only the area of the integrated taillights. 5

After coating the outer skin, the plastic molded part 1 is completed and can be used in the vehicle. It has on the outer side 23 a correspondingly high resistance to shocks, bumps, scratches or UV radiation. As in this embodiment too can recognize, can thus be produced 1 molded parts with curved geometries.

Fig. 3 shows a further exemplary embodiment of a plastic molded part 1, in this case a roof element 27 for a motor vehicle. This roof element 27 must on the one hand at the edges 29, as shown, with a decor 31 in the form of opaque, for example, black dots 33 are provided. All other areas of the roof element 27 should be transparent. Furthermore, such a roof element 27, whose outer side 35 is constantly exposed to influences by the environment, high demands in terms of scratch, shock and wear resistance and resistance to UV radiation.

In this embodiment, the ink layer 17 comprises the dots 33 arranged at the edges 29. The other regions of the film 13 which are later to be transparent are accordingly not printed.

In Fig. 4, a detailed view of the roof element 27 is shown. The structure of the cross section substantially corresponds to that in FIG. 2 shown cross-section of the bumper 3, with the difference that here between the ink layer 17 and the back-injected plastic layer 25, a bonding agent 37 ^' is provided, since the plastic layer 25 and film 13 are made of different materials and therefore possibly. not stick together so well.

The preparation of the roof element 27 is similar to that of the bumper 3 of FIG. 1, with the difference that the scratch-resistant layer 21 is not sprayed on the film 13 here, but is connected directly to this during the production of the film 13 by a co-extrusion process. Coextrusion processes are already well known in industrial practice. It is possible to produce a multilayer film composed of up to seven layers by coextrusion. In this case, the application of the color layer 17 takes place on a two-layer composite already consisting of film 13 and scratch-resistant layer 21.

Such an integrated roof element 27 can therefore be produced easily and in a few process steps using the method.

Depending on the application, the order of the process steps for producing the plastic molded part 1 may vary. For example, it is possible in principle to apply the scratch-resistant layer 21 to the film 13 at six different times in the course of the process: It can

- Before the application of the ink layer 17 on the film 13,

after application of the color layer 17 to the film 13,

before the thermoforming of the film 13,

after deep drawing of the film 13,

- Before the injection of the plastic layer 25 or

- Be applied to the back of the plastic layer 25 on the outside 19 of the film 13. In the first case, it can, as shown in the second embodiment, be coextruded together with the film 13, while it is applied in the other cases, for example by spraying. The method is therefore very flexible and can be used to produce a wide range of plastic moldings 1.

Another application in addition to the production of plastic moldings 1 with different printed areas is the Application of a color layer 17 made of an electrically conductive material.

Thus, it is possible, for example, a transparent roof element 27 as shown in FIG. 3 with an integrated antenna using the method produce. Furthermore, heating elements in the form of printed heating wires can thus be introduced directly as a color layer, for example in the case of rear windows. Antenna and heating wires are protected by the film 13 and the scratch-resistant layer 21 from the environment.

Furthermore, all combinations of printed areas, transparent areas with opaque or transparent or electrically conductive dyes in a color layer 17 can be produced by this method, with the great advantage that the moldings thus produced are used because of the scratch-resistant layer 21 everywhere on the outside of a motor vehicle can.

Further exemplary embodiments are all plastic parts arranged on the outside of the motor vehicle body, which have differently colored and / or transparent regions or incorporated conductive elements. These may be, for example, light covers, especially for taillights, brake lights or turn signals, which are installed individually or integrated into existing elements such as exterior mirror housings, windows or bumpers. Conceivable is the use of such plastic moldings 1 as rear windows or side windows, as transparent roofs, as exterior mirror housings with integrated turn signal or other integrated display elements, eg. B. for parking aids. The invention is not limited to the illustrated methods or moldings. Depending on the application, for example, the order of the individual process steps can be changed.

Furthermore, in addition to the illustrated thermoforming process with the help of vacuum, another thermoforming process is conceivable, for example deep drawing under pressure and / or temperature.

Furthermore, in addition to the two presented another printing method is conceivable, for example, a pad printing process.

The adhesion promoter 37 can furthermore also be extruded directly with the film 13 and the scratch-resistant layer 21. For the scratch-resistant layer 21, a different material can be used in addition to the material PMMA.

Claims

claims

1. A process for producing a plastic molding (1) from a film material (14) made of transparent plastic, wherein the film material (14) is printed by means of a printing process on one side by a

Deep-drawing process is formed and after the forming of the printed page (15) ago with a transparent

Plastic (25) is injected behind, characterized in that the film material (14) on its side remote from the printed side (15) outside (19) with a scratch-resistant layer (21) is provided.

2. The method according to claim 1, characterized in that the film material (14) is printed by means of a screen printing process.

3. The method according to claim 1, characterized in that the film material (14) is printed by means of an ink-jet printing process.

4. The method according to any one of claims 1 to 3, characterized in that as the color layer (17), an electrically conductive material is used.

5. The method according to claim 4, characterized in that the ink layer (17) made of electrically conductive material as an in the plastic molding (1) integrated antenna is used.

6. The method according to claim 4, characterized in that the ink layer (17) made of electrically conductive material as a in the plastic molding (1) integrated heating element is used.

7. The method according to any one of claims 1 to 6, characterized in that the scratch-resistant layer (21) by spraying a Siloxanlacks on the film material (14) is generated.

8. The method according to any one of claims 1 to 6, characterized in that the provided with a scratch-resistant layer (21) foil material (14) is produced by a co-extrusion process.

9. plastic molding (1) with a transparent plastic film (13), a back-injected layer (25) made of transparent plastic, and a color layer

(17) between plastic film (13) and back-injected plastic layer (25), characterized in that the plastic molding (1) to the the ink layer (17) opposite side of the plastic film (13) adjacent layer ( 21) comprises a scratch-resistant plastic.

10. Plastic molding according to claim 9, characterized in that the plastic film (13) consists of polycarbonate.

11. Plastic molded part according to claim 9 or 10, characterized in that the scratch-resistant plastic layer (21) consists of Polymehtylmethacrylat (PMMA).

12. Plastic molding according to one of claims 9 to 11, characterized in that on the side facing away from the scratch-resistant layer (21) side of the plastic film (13) a layer of a bonding agent (37) is arranged.