EP1672609A2 - Composite plastic piece - Google Patents

Abstract

The plastic part has a transparent carrier part with superimposed layers having two opposite sides (2a, 2b). An optical active layer is superimposed on one of the sides of the carrier part in partial regions and is attached to a face plate. The face plate prevents light permeability in sub regions. The face plate is illuminated from back side with a light source. The light source is arranged as self luminescent display. Independent claims are also included for the following: (A) a method for manufacturing a multilayer laminar plastic part (B) an utilization of the multilayer laminar plastic part.

Description

The invention relates to a multilayer plastic sheet-like part for decorative elements and / or display and functional elements, such as, for example, application in the automotive industry, in particular at manhole covers, trim panels and function displays found.

It is known, as taught by DE 201 05 140 U1, a backlit plastic part for display and / or functional elements. This consists of a transparent polymer material, which is vapor-deposited on the visible side with a thin metal layer. For protection, for example against mechanical damage, a scratch-resistant paint is usually applied to the metal layer.
As lighting fixtures, one or more spotlights illuminating spot or surfaces are provided behind or in the plastic part, so that diffuse light emerges on the visible side at least in the region of the illuminated field through the metal layer. Optionally, display symbols or decorative elements can be introduced into the surface, for example by means of laser structuring, so that the light can pass through unhindered there.

A disadvantage of this embodiment is in particular the fact that the optically and / or functionally relevant layers are on the surface (visible side) of the component and therefore must be protected by a transparent cover layer against chemical and mechanical influences.
Furthermore, due to the overhead metal layer results in a surface without depth effect and with reduced brilliance.
Finally, the metal layer of the backlightable plastic part is protected only on the surface, but not laterally, so that a corrosive infiltration of the metal layer can easily occur.

However, it is particularly disadvantageous that surface structuring, which is often desired for design reasons, is not or only possible to a very limited extent.
As a result of the structuring, there are depressions on the surface, which not only pollute very easily, but are also difficult to clean beyond.

Starting from the disadvantages of the described prior art, the object is to provide a functional part and / or trim part in the form of a plastic part, which has an easy-to-clean, smooth and resistant surface, shows a brilliant, metallic gloss with depth effect and in the built-in state, even in chemically aggressive environment has a long service life. Another object is to provide a variety of optical effects on the functional part and / or trim part available.

The object could be achieved by a multilayer plastic part with the features of claim 1.
Preferred embodiments and further developments can be found in the subclaims.
The method for producing the multilayer plastic part is carried out according to the features of claim 15.

According to the invention, the optically effective, but scratch-sensitive layer, for example in the form of a thin metal layer, is applied to the sheet-like plastic part, which comprises two sides, on the first side. This side is the side of the part opposite the visible side in the installed state. The two sides of the sheet-like plastic part face each other.

As a result, it is achieved in a very advantageous manner according to the invention that the transparent plastic part not only serves as a carrier for the applied coatings, but also functions as its protective layer.
On the one hand, there is a surface which is resistant to mechanical stress, on the other hand, the scratch-resistant coating of the optically active layer can be dispensed with.

Furthermore, the inventive design of the plastic part allows structuring of the first side of the part.
As a result, a variety of optical effects can be realized.

Likewise, a contamination of the wells is prevented, especially since such plastic part according to the invention can be preserved by suitable arrangement and encapsulation / sealing in the installed state against the ingress of dirt.

Due to the thickness of the transparent plastic part, which is generally about 1 to 5 mm, optically results in the desired depth effect of the multilayer structure according to the invention in the form of a particularly brilliant image of the optically active layer and the introduced structures.

According to the invention, the plastic part has decorative elements and functional elements.
For this purpose, the following structure is proposed, wherein the layer sequence is described as follows:

The plastic part consists of a carrier part made of a polymer, on the sides of which layers are applied. The support member is designed substantially flat, here for the inventive idea relevant sides of the support member are opposite.

The transparent support member itself is made of polycarbonate or polystyrene or polyethylene terephthalate or polymethylmethacrylate or their mixed compositions and compounds.
The polymer material is preferably colorless, highly transparent and clear.
In other embodiments of the invention, a colored, less transparent, in particular an opaque material can also be used.
As a result, special light scattering effects can be achieved.
In a further embodiment of the invention, it is also possible to use a so-called light-collecting plastic which "edges off" the light irradiated over the surfaces, thereby achieving special design effects.

On the second side of the plastic part, ie the side facing the viewer in the installed state, a metal or plastic film can be applied, which can partially or completely cover the transparent support part.

This layer is preferably attached to the outer boundary of the plastic part, wherein the part is preferably a piece covered in the edge region and so forms a frame assembly that can hold the plastic part, for example, in the installed position. This layer can be provided with decors and thereby be upgraded in a special way visually.

The first side of the carrier part is provided according to the invention with the optically active layer.

In a preferred embodiment of the invention, the first side of the carrier part is structured.

The structure may be defined macroscopically - for example by a groove structure - or by surface fine structures such as satin-like textures, brush textures, stochastic or directional groove textures.

Such structures can be very easily introduced into the carrier part by a corresponding design of the injection molding tool, as far as the carrier part is produced by injection molding.
For this purpose, the corresponding surface, which is intended to image a structure on the carrier part to be produced by injection molding on its first side, is designed in accordance with the negative shape of the structure.

Other techniques for introducing structures onto the first surface include e.g. As laser techniques, beam techniques, milling techniques, engraving techniques, and others.

The second side of the carrier part is preferably formed smooth, but it can also be provided there the introduction of structures in the surface.

The further layer structure of the plastic part according to the invention is as follows.

An optically active layer is applied to the optionally provided with structures first side of the support member.

As optically active layers, layers of metals, such as aluminum (Al) or chromium (Cr), but also of metal alloys consisting of chromium and aluminum or nickel and chromium, or of metal compounds, such as titanium nitride (TiN) or titanium carbide (TiC) or other colored translucent layers, such as paint, color or foil layers serve.

The layer thickness is preferably chosen such that the light transmission of the layer is in the range between 0 and 70%, preferably in the range between 10 and 30%.

1. 1. durch vakuumtechnische Verfahren wie thermisches Verdampfen und/oder Sputtertechnik und/oder kathodische oder anodische Bogenverdampfung und/oder E-lektronenstrahlverdampfung und/oder Strahlablationsverfahren als Laserstrahlablation und/oder Elektronenstrahlablation
   und/oder
2. 2. durch nasschemische Metallisierungsverfahren wie außenstromloses Vernickeln und/oder reduktive Abscheidung
   und/oder
3. 3. durch galvanische Metallabscheideverfahren
   und/oder
4. 4. durch metallpigmentierte Lack- oder Folienbeschichtungen.

The optically active layer is prepared as follows:

1. 1. by vacuum technology methods such as thermal evaporation and / or sputtering technique and / or cathodic or anodic arc evaporation and / or E-lektronenstrahlverdampfung and / or Strahlablationsverfahren as laser beam ablation and / or electron beam ablation
   and or
2. 2. by wet-chemical metallization processes such as electroless nickel plating and / or reductive deposition
   and or
3. 3. by galvanic Metallabscheideverfahren
   and or
4. 4. by metal-pigmented paint or foil coatings.

To produce the finest optical structures, the optically active layer can be completely or partially removed again in desired regions, in particular by the action of laser radiation, it being possible to produce, for example, dot arrangements, close-meshed line screens or other - in particular very finely structured - geometric patterns and markings.
As a result, in particular zones of higher light transmission can be produced.

By means of the laser ablation process, complete or partial ablation of the metal layer can be achieved starting from the first side and / or second side of the plastic part. For this purpose, the laser beam strikes the optically active layer, which is arranged on the first side and dissolves the metal layer by heating and Absprengprozesse. This can also be done on the second side of the plastic part.

Partial ablation of the optically active layer results in contrast effects. In this case, for example, the following contrast situations can be generated at adjacent locations on the surface of the plastic part:
"Semi-translucent to opaque" or "Semi-translucent to completely translucent", which additional designerische opportunities for highlighting example of fonts, marks or symbols on the surface of the component are possible.
In particular, light transmissions can thus be produced which are freely selectable from completely translucent to partially translucent to substantially opaque.

The optically active layer is flat, but only partially covered by a panel. The aperture function results advantageously by a print.
For this purpose, by means of a suitable application method of a coating composition, for example the printing of a printing ink or a covering lacquer, which can be adjusted in black, white or color, a covering-agent-covering covering agent layer is applied.
This layer is chosen in its thickness so that it does not allow light to pass through and therefore acts as a diaphragm.
In addition, a design effect can be achieved by the choice of color by the coloring made visible in the thus produced screen from the visible side.

If the plastic part according to the invention is used in a chemically particularly aggressive environment, the layer composite of optically active layer and aperture can additionally be provided with a transparent protective lacquer.
In this embodiment, the coating and the printing is not applied to the edges of the transparent plastic part, so that the layer composite, covered by the resist, a chemical attack is not accessible.
As a result, particular advantages in terms of the durability of the composite layer are achieved.

The plastic part according to the invention can furthermore be combined with a light source.

The light source is preferably arranged so that it radiates through the plastic part according to the invention by directing light onto the first side of the carrier part, and - after passage of the light through the carrier part - this emerges on the second side of the carrier part.

However, the light source can also be arranged laterally of the carrier part or directly in the carrier part.

This can be special lighting effects when highlighting fonts, markers and symbols achieve.

The light source may consist of a thin, current-fed luminous film (eg an electroluminescent film), but are, depending on the application, also versions with a so-called. Mini-fluorescent tube, or with LED arrangements (light-emitting diodes, light emitting diode) on an organic or inorganic basis , or with miniature incandescent lamps, or with miniature lamps, or with laser light sources, or with plasma light sources possible.

In another embodiment of the invention, light can also be guided by means of optical fibers which are arranged between the light source and the carrier part, the optical fibers having a conductive and / or focusing and / or scattering effect on the guided light.

Likewise, a self-illuminating foil display can be arranged as a "backlighting source". In this case, the plastic part according to the invention serves as a metallic display cover. This version can be used for displays. If one uses a plastic part according to the invention as a trim panel and couples it with a stored display, the system functions as a visually particularly high-quality display unit.

If the light source, preferably in the dark, activated, a so-called night design can be generated - for example, in conjunction with a suitable metallization and / or structuring and / or printing - which also serves the lighting simultaneously.

If a particularly high level of mechanical abrasion and / or a particular chemical load is to be expected or if a special appearance is desired, the optional metal or plastic film on the second side, which represents the visible side, can additionally - over the entire surface or optionally partially - with a scratch-resistant coating be provided that is colorless or colored transparent or colored semi-transparent.

In the following, the invention as embodiment of an entry rail for a car will be explained in more detail on an exemplary embodiment, which is not intended to limit the invention, wherein FIG. 1 shows the layer structure according to the invention in cross section.

The multilayer flat plastic part (1) consists of a carrier part (2).
The support part (2) of a transparent polymer material has a wall thickness of about 3.0 mm, it is on the second side (2b) partially covered with a foil (3) made of stainless steel, on the first side (2a) are structures applied in a section (2c).
It is vapor-deposited on the first side (2a) with an optically active layer (4) of aluminum in a thickness of about 50 nm, wherein parts of the aluminum layer (4) were removed by laser ablation in the section (2d).
The aluminum layer (4) is partially covered with a diaphragm (5) of black ink of a thickness of about 15 microns. In order to protect the metallization zone in section (2d), the sealing takes place with a transparent lacquer (6).
This layer composite is finally partially laminated on the first side with a light-emitting electroluminescent film (7).

The multilayer plastic part is produced by the following method:

The metal and / or plastic film (3) is first preformed, for example, by pressing it over a negative mold.
The preformed film (3) is then punched in a device and / or trimmed by means of a laser.
The trimmed film (3) is placed in an injection mold, which can be done by means of a robot, as this high positioning accuracy is achieved.

• Focusdurchmesser 40 µm
• Lampenstrom 17,7 A
• Verfahrgeschwindigkeit 1000 mm/s
• Modenblende 1,3
• Jump Delay 800 µs
• Mark Delay 20 µs
• Spurversatz 10 µm

bei Laserlichteinstrahlung eine vollständige Entmetallisierung einer aluminiumbeschichteten Polycarbonat-Oberfläche erreicht werden.
Eine Maskierung der Bereiche, also die Erzeugung einer Blende (5), durch die kein Licht auf der zweiten Seite (2b) austreten soll, wird als letzter Herstellschritt durchgeführt.
Dies geschieht durch Bedruckung (z. B. mittels Tampondruck) oder Maskierung und Lackierung mit lichtundurchlässigen Beschichtungsmitteln, wobei die Blende (5) erzeugt wird. Hierbei ist die genaue Positionierung des Bauteils und eine scharfkantige Bedruckung sicherzustellen, um eine genaue Überdeckung mit den Strukturen zu erreichen und um evtl. Lichtstreuungen zu verhindern.The injection molding tool has the structure to be imaged (design) on the surface producing the first side of the component (2a) and is, for example, finished on the opposite surface (eg PVD-evaporated) in order to produce a particularly high-quality second side (2b) of the part ,
The film (3) is injected in the injection mold with a transparent plastic (eg a polycarbonate) behind.
The intermediate component thus produced is placed in a metallization plant. A mask covers the areas where no metal is to be deposited.
In the magnetron sputtering method, a thin metal layer (4) is subsequently applied, the layer thickness of this metal layer (4) being chosen to be less than 700 nm. Used are chromium or chromium-aluminum alloys, which have a high self-corrosion protection.
The applied layer (4) can be partially removed again (eg with a laser by so-called "laser ablation").
For example, when using an Nd: YAG 1064 laser in continuous wave operation with the parameters

• Focus diameter 40 μm
• Lamp current 17.7 A
• Travel speed 1000 mm / s
• Mode aperture 1.3
• Jump Delay 800 μs
• Mark Delay 20 μs
• Track offset 10 μm

In laser light irradiation, a complete demetallization of an aluminum-coated polycarbonate surface can be achieved.
A masking of the regions, that is to say the generation of a diaphragm (5) through which no light is to emerge on the second side (2b), is carried out as the last production step.
This is done by printing (eg by means of pad printing) or masking and painting with opaque coating agents, whereby the diaphragm (5) is produced. In this case, the exact positioning of the component and a sharp-edged printing must be ensured in order to achieve precise coverage with the structures and to prevent possible light scattering.

The layer composite can be provided with a protective lacquer (6). This protects the metal layer (4) from external influences, in particular from corrosion. The selection of a suitable protective lacquer (6) makes special demands, since it is in contact with both the polymer material of the support part (2), as well as the metal layer (4) and the diaphragm (5). The protective lacquer (6) ensures the adhesion and is formulated such that in particular the metal layer (4) is not dissolved or attacked.

Claims (15)

Multilayer plastic sheet part (1) for decorative elements and / or functional elements comprising a transparent carrier part (2) with applied layers, two opposing sides (2a, b) having , characterized in that on a first side (2a) of the carrier part (2 ) is applied at least in some areas an optically active layer (4), which is associated with a diaphragm (5), which prevents the light transmission in partial areas, and which is backlit with a light source (7). Multilayer plastic part (1) according to Claim 1, characterized in that the transparent carrier part (2) has sections (2c) with structures on the first side (2a). Multilayer plastic part (1) according to one of the preceding claims, characterized in that the material of the optically active layer (4) is selected from the group of metals and / or metal alloys and / or metal compounds and / or paints and / or films. Multilayer plastic part (1) according to claim 1 or 3, characterized in that the light transmittance of the optically active layer (4) is 0 to 70%, preferably 10 to 30%. Multilayer plastic part (1) according to any one of claims 1, 3 or 4, characterized in that in the optically active layer (4) structures are introduced, resulting in area-related different light transmission properties of the layer (4). Multilayer plastic part (1) according to claim 5, characterized in that the introduced structures completely or partially penetrate the optically active layer (4), resulting in fully transparent or partially transparent coating areas. Multilayer plastic part (1) according to Claims 5 and 6, characterized in that the structures introduced into the optically active layer (4) are produced in particular by means of laser ablation. Multilayer plastic part (1) according to one of the preceding claims, characterized in that the transparent carrier part (2) on the second side (2b) is partially covered with a foil (3) made of plastic and / or metal. Multilayer plastic part (1) according to one of the preceding claims, characterized in that the layer composite of film (3), transparent carrier part (2), optically active layer (4) and diaphragm (5) on the layer composite of the first side (2a) of a protective layer (6) is coated. Multilayer plastic part (1) according to one of the preceding claims, characterized in that the layer composite of film (3), transparent carrier part (2), optically active layer (4) and diaphragm (5) on the first side (2a) with a light source (7) is combined. Multilayer plastic part (1) according to claim 8, characterized in that the light source (7) is selected from the group comprising luminescent film, in particular electroluminescent film, mini-fluorescent tube, LED (light emitting diode), organic LED, miniature lamp, miniature lamp or laser or plasma light source. Multilayer plastic part (1) according to one of the preceding claims, characterized in that optical fibers are arranged between the carrier part (2) and the light source (7) with a conductive and / or focusing and / or scattering effect. Multilayer plastic part (1) according to one of the preceding claims, characterized in that a self-luminous display is arranged as the light source (7). Use of a multilayer sheet-like plastic part (1) according to one of Claims 1 to 13 for decorative elements and / or display and functional elements in the automotive industry, in particular for entrance rail covers, trim panels and function displays. A method for producing a multilayer plastic sheet part (1) according to claim 1 to 13, characterized in that on at least a first side (2a) of the carrier part (2) an optically effective layer (4) is applied at least in partial areas, which has a diaphragm (5 ).

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