DE102010015056A1 - Method for manufacturing carrier component that is utilized in e.g. interior region of motor car, involves coating foam structure with soft component under specific pressure for formation of coating on surface area of foam structure - Google Patents

Abstract

The method involves injecting a melted thermoplastic component containing a blowing agent into a mold cavity (6) in a molding tool (3) such that the mold cavity is filled with the thermoplastic component, where the thermoplastic component foams within the mold cavity to form an integral foam structure. The integral foam structure is demolded and introduced into a coating device. The integral foam structure is coated with a soft component i.e. polyurethane paint, under pressure from 10-100 bar for formation of a coating on a surface area of the integral foam structure.

Description

The present invention relates to a method for producing a coated plastic component.

Methods for producing coated plastic components by injection molding and subsequent coating thereof with a soft component, in particular with a polyurethane component, are already known from the prior art in various embodiments. Examples of this are the US 6,497,782 B , the WO 07 135 033 A1 as well as the DE 10 2006 052 316 A1 ,

Polyurethanes are suitable as coatings for plastic components due to their high resistance to solvents, chemicals and weathering. When coating a surface of a plastic component produced by injection molding, in particular a carrier component, with a polyurethane coating (short: PU coating), a low-distortion and incidence-free component surface must be ensured, so that a high quality of the coating can be obtained. This requirement can not always be guaranteed especially for compact, large-area and ribbed plastic components which are produced by conventional injection molding methods.

To remedy this problem, it is already known from the prior art to produce plastic components by thermoplastic foam injection molding. In this case, a gas loading of the plastic melt used for the production of the component with chemical or physical blowing agents for foaming within the mold cavity and to form a so-called Integralschaumstrukur inside the molding, resulting in many advantages over the conventional injection molding. In particular, thermoplastic foam injection molding processes can be used to produce plastic components which are lighter, less distortion-prone and less random and, moreover, have high rigidity and dimensional stability. However, the plastic components produced by such a thermoplastic foam injection molding method have a schlierige, optical claims not sufficiently fair expectant surface, so that they can not be used in a visible area without a corresponding coating. For the use of a plastic component produced by thermoplastic foam injection molding in a field of view - for example in a field of vision of a motor vehicle - the plastic component with an additional coating component would have to be (at least partially) coated / overmolded. If a (second) thermoplastic component is injected into the mold as the coating component, there is the problem that due to the high injection pressures, which are typically higher than 500 bar, the integral foam structure of the plastic component is very strongly and, above all, irreversibly compressed, so that the mechanical properties of the component are significantly deteriorated. This is particularly problematic when the plastic component is to be used as a carrier component.

This is where the present invention sets in and has set itself the task of providing a simple and process-reliable process for the production of a coated plastic component which is low on incidence and low distortion and has a high-quality surface coating.

The solution of this object provides a method for producing a coated plastic component with the features of claim 1. An alternative solution to this problem provides a method for producing a coated plastic component having the features of claim 2. The subclaims relate to advantageous developments of the invention.

• – Bereitstellen eines Formwerkzeugs, das einen Formhohlraum definiert;
• – Einspritzen einer geschmolzenen, ein Treibmittel enthaltenden thermoplastischen Komponente in den Formhohlraum, so dass der Formhohlraum mit der thermoplastischen Komponente gefüllt wird und die thermoplastische Komponente innerhalb des Formhohlraums aufschäumt und eine Integralschaumstruktur bildet;
• – Entformen der Integralschaumstruktur;
• – Einbringen der Integralschaumstruktur in eine Beschichtungseinrichtung; Beschichten der Integralschaumstruktur mit wenigstens einer Weichkomponente unter einem Druck von 10 bis etwa 100 bar zur Bildung einer Beschichtung auf der Oberfläche der Integralschaumstruktur. Das erfindungsgemäße Verfahren kombiniert in besonderes vorteilhafter Weise ein Thermoplast-Schaumspritzgussverfahren zur Herstellung einer aufgeschäumten thermoplastischen Komponente, die eine Integralschaumstruktur bildet und damit besonders leicht, verzugsarm und einfallsstellenarm ist und darüber hinaus eine hohe Steifigkeit sowie Maßhaltigkeit aufweist, mit einer nachträglichen Beschichtung der Integralschaumstruktur mit zumindest einer Weichkomponente. Dadurch, dass das Beschichten der Integralschaumstruktur mit der wenigstens einen Weichkomponente bei einem Druck von lediglich 10 bis etwa 100 bar, insbesondere bei einem Druck von 40 bis etwa 60 bar erfolgt, kann in besonders vorteilhafter Weise eine irreversible, aus mechanischer Sicht nicht tolerierbare Stauchung der Integralschaumstruktur wirksam vermieden werden.

A method for producing a coated plastic component according to a first variant of the invention comprises the steps

• Providing a mold defining a mold cavity;
• Injecting a molten propellant-containing thermoplastic component into the mold cavity so that the mold cavity is filled with the thermoplastic component and foams the thermoplastic component within the mold cavity and forms an integral foam structure;
• - demolding the integral foam structure;
• - introducing the integral foam structure into a coating device; Coating the integral foam structure with at least one soft component under a pressure of from 10 to about 100 bar to form a coating on the surface of the integral foam structure. The inventive method combines in a particularly advantageous manner a thermoplastic foam injection molding process for producing a foamed thermoplastic component which forms a integral foam structure and thus is particularly easy, low distortion and low incidence and also has a high rigidity and dimensional stability, with a subsequent coating of the integral foam structure with at least a soft component. Characterized in that the coating of the integral foam structure with the at least one soft component at a pressure of only 10 to about 100 bar, in particular at a pressure of 40 to about 60 Bar occurs, can be effectively avoided irreversible, not tolerable from a mechanical point of view compression of the integral foam structure.

• – Bereitstellen eines Formwerkzeugs, das einen Formhohlraum definiert; Einspritzen einer geschmolzenen, ein Treibmittel enthaltenden thermoplastischen Komponente in den Formhohlraum, so dass der Formhohlraum mit der thermoplastischen Komponente gefüllt wird und die thermoplastische Komponente innerhalb des Formhohlraums aufschäumt und eine Integralschaumstruktur bildet;
• – Einspritzen wenigstens einer Weichkomponente unter einem Druck von 10 bis etwa 100 bar in den Formhohlraum zur Bildung einer Beschichtung auf der Oberfläche der Integralschaumstruktur;
• – Entformen des Kunststoffbauteils.

According to an alternative variant of the invention, a method for producing a coated plastic component comprises the steps

• Providing a mold defining a mold cavity; Injecting a molten propellant-containing thermoplastic component into the mold cavity so that the mold cavity is filled with the thermoplastic component and foams the thermoplastic component within the mold cavity to form an integral foam structure;
• Injecting at least one soft component under a pressure of from 10 to about 100 bar into the mold cavity to form a coating on the surface of the integral foam structure;
• - Mold removal of the plastic component.

Also in this process variant, a thermoplastic foam injection molding process for producing a foamed thermoplastic component, which forms an integral foam structure and thus is particularly easy, low distortion and low incidence and also has a high rigidity and dimensional stability, with a subsequent coating of the integral foam structure in a particularly advantageous manner at least one soft component combined. Due to the fact that the coating of the integral foam structure with the at least one soft component takes place at a pressure of 10 to about 100 bar, in particular at a pressure of 40 to about 60 bar, an irreversible, from a mechanical point of view intolerable compression of the integral foam structure can be achieved in a particularly advantageous manner can also be effectively avoided. This variant of the method also has the advantage that the production of the plastic component can be carried out completely within the mold. In other words, therefore, the integral mold structure does not have to be removed from the mold, as in the first method variant, and then introduced into a coating device in which the soft component is applied to the surface of the integral mold structure. The manufacturing process of the plastic component takes place in this process variant to a certain extent "one-stage", so that the tool and manufacturing costs can be reduced in an advantageous manner.

The plastic components produced with the aid of the two inventive methods presented here are particularly suitable as carrier components and can be used, for example, in the interior or exterior area of a motor vehicle. Due to their coating, the plastic components can also be used in visible areas.

In a particularly advantageous embodiment, it is proposed that the soft component is sprayed onto the surface of the integral foam structure. The soft component may in particular be in the form of a lacquer which is sprayed onto the surface of the integral foam structure or injected into the mold cavity of the mold to form the coating of the integral foam structure.

In one preferred embodiment, the integral foam structure may be partially coated with the soft component, in particular in a region which forms a visible side in the subsequent use of the plastic component. In a further advantageous embodiment, there is the possibility that the integral foam structure is completely coated with the soft component.

In a particularly preferred embodiment, it is proposed that a polyurethane coating component be used as a soft component to form the coating of the surface of the integral foam structure. Polyurethanes have the advantage that they are particularly suitable as coatings of plastic components because of their high resistance to solvents, chemicals and weathering. In particular, it is possible to use a polyurethane lacquer which is sprayed onto the surface of the latter or injected into the mold cavity of the mold to form the coating of the integral foam structure. A polyurethane paint is characterized in particular by good processability.

Further features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Show in it

1 a schematic representation of a mold, which is suitable for carrying out a method for producing a coated plastic component according to a preferred embodiment of the present invention;

2a and 2 B a schematic representation of the mold according to 1 during the step of injecting a thermoplastic component into a mold cavity of the mold;

3 a schematic representation of the mold after the foaming of the thermoplastic component to form an integral foam structure;

4 a schematic representation of the mold during the process step of injection of a soft component for coating the surface of the integral foam structure;

5 a schematic representation of a plastic component, with the aid of in 2a to 4 described method was prepared.

In 1 is a mold 3 schematically shown greatly simplified, that for carrying out a method for producing a coated plastic component 1 according to a preferred embodiment of the present invention is suitable. The mold 3 includes a first mold half 4 and a second mold half 5 which are movable relative to each other, so that the mold 3 optionally closed and reopened. In the closed position, the two mold halves define 4 . 5 of the mold 3 a mold cavity 6 , whose contour to the outer contour of the means of the mold 3 to be produced plastic component 1 is adjusted. The first mold half has a first injection opening 7 and a second injection port 8th open, which can be opened and closed again.

In a first step, in 2a and 2 B is shown is when the mold is closed 3 and opened first injection port 7 a molten thermoplastic component 9 containing a blowing agent in the mold cavity 6 injected so that the mold cavity 6 with the thermoplastic component 9 is filled. The second injection port 8th is closed during this injection process. The injection pressure during the injection of the thermoplastic component 9 into the mold cavity 6 typically is about 500 to 1200 bar.

As in 3 illustrates, the thermoplastic component expands 9 due to the chemical or physical blowing agent contained therein within the mold cavity 6 and foams up to a rigid foam, the integral foam structure 10 forms.

Subsequently, a soft component 11 , which preferably contains polyurethane, under a pressure of 10 to about 100 bar, in particular under a pressure of 40 to about 60 bar through the second injection port 8th into the mold cavity 6 injected. The soft component 11 forms a coating 2 for the surface of the integral foam structure 10 of the plastic component 1 , The first injection opening 7 of the mold 3 is during injection of the soft component 11 into the mold cavity 6 closed.

In the embodiment described above, both the foaming of the thermoplastic component 9 to form the integral foam structure 10 and their coating with the soft component 11 inside the mold cavity 6 of the mold 3 carried out. The manufacturing process of the plastic component 1 takes place in this process variant to a certain extent "single-stage", so that the tool and manufacturing costs can be reduced.

• – Bereitstellen eines Formwerkzeugs 3, das einen Formhohlraum 6 definiert;
• – Einspritzen einer, ein Treibmittel enthaltenden thermoplastischen Komponente 9 in den Formhohlraum 6, so dass der Formhohlraum 6 mit der thermoplastischen Komponente 9 gefüllt wird und die thermoplastische Komponente 9 innerhalb des Formhohlraums 6 aufschäumt und eine Integralschaumstruktur 10 bildet;
• – Entformen der Integralschaumstruktur 10;
• – Einbringen der Integralschaumstruktur 10 in eine Beschichtungseinrichtung;
• – Beschichten der Integralschaumstruktur 10 mit wenigstens einer Weichkomponente 11, insbesondere mit einer Polyurethankomponente, bei einem Druck von 10 bis etwa 100 bar, insbesondere bei einem Druck von 40 bis etwa 60 bar zur Bildung einer Beschichtung 2 auf der Oberfläche der Integralschaumstruktur 10.

According to a second variant, not explicitly shown here, a method for producing a plastic component comprises 1 the steps

• - Providing a mold 3 Having a mold cavity 6 Are defined;
• - Injection of a propellant containing thermoplastic component 9 into the mold cavity 6 so that the mold cavity 6 with the thermoplastic component 9 is filled and the thermoplastic component 9 inside the mold cavity 6 foams and an integral foam structure 10 forms;
• - demolding the integral foam structure 10 ;
• - introducing the integral foam structure 10 in a coating device;
• - coating the integral foam structure 10 with at least one soft component 11 , in particular with a polyurethane component, at a pressure of 10 to about 100 bar, in particular at a pressure of 40 to about 60 bar to form a coating 2 on the surface of the integral foam structure 10 ,

This variant of the method is particularly suitable in particular when the surface of the integral foam structure 10 completely with a coating 2 should be provided.

In 5 is a plastic component 1 represented by one of the two methods described above and an integral foam structure 10 with a coating 2 having the integral foam structure 10 completely surrounds. Basically, the surface of the integral foam structure 10 completely or even partially with the coating 2 consisting of the soft component 11 exists, be provided.

The two methods presented here combine in a particularly advantageous manner a thermoplastic foam injection molding process for producing a foamed thermoplastic component 9 that have an integral foam structure 10 forms and thus is particularly easy, low distortion and low incidence and also has a high rigidity and dimensional stability, with a subsequent coating of the integral foam structure 10 with a soft component 11 , in particular with a polyurethane component. By doing that Coating the integral foam structure 10 with the at least one soft component 11 is carried out at a pressure of 10 to about 100 bar, in particular at a pressure of 40 to about 60 bar, an irreversible, not tolerable from a mechanical point of view compression of the integral foam structure 10 can be effectively avoided in a particularly advantageous manner.

Polyurethane components, preferably as soft components 11 for coating the integral foam structure 10 have the advantage that they are due to their high resistance to solvents, chemicals and weathering in particular as coatings 2 of plastic components 1 suitable. In particular, it is possible to use a polyurethane varnish which is used to form the coating 2 the integral foam structure 10 is sprayed on the surface or in the mold cavity 6 of the mold 3 is injected. A polyurethane paint is characterized in particular by good processability.

LIST OF REFERENCE NUMBERS

1

Plastic component

2

coating

3

mold

4

first half of the mold

5

second mold half

6

mold cavity

7

first injection opening

8th

second injection port

9

thermoplastic component

10

Integral foam structure

11

soft component

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6497782 B [0002]
• WO 07135033 A1 [0002]
• DE 102006052316 A1 [0002]

Claims (8)

Process for producing a coated plastic component ( 1 ), comprising the steps - providing a molding tool ( 3 ), which has a mold cavity ( 6 ) Are defined; Injecting a molten propellant-containing thermoplastic component ( 9 ) in the mold cavity ( 6 ), so that the mold cavity ( 6 ) with the thermoplastic component ( 9 ) and the thermoplastic component ( 9 ) within the mold cavity ( 6 ) and an integral foam structure ( 10 ) forms; Demolding the integral foam structure ( 10 ); Introduction of the integral foam structure ( 10 ) in a coating device; - coating the integral foam structure ( 10 ) with at least one soft component ( 11 ) under a pressure of 10 to about 100 bar to form a coating ( 2 ) on the surface of the integral foam structure ( 10 ). Process for producing a coated plastic component ( 1 ), comprising the steps - providing a molding tool ( 3 ), which has a mold cavity ( 6 ) Are defined; Injecting a molten propellant-containing thermoplastic component ( 9 ) in the mold cavity ( 6 ), so that the mold cavity ( 6 ) with the thermoplastic component ( 9 ) and the thermoplastic component ( 9 ) within the mold cavity ( 6 ) and an integral foam structure ( 10 ) forms; Injecting at least one soft component ( 11 ) under a pressure of 10 to about 100 bar in the mold cavity ( 6 ) to form a coating ( 2 ) on the surface of the integral foam structure ( 10 ); Demolding the plastic component ( 1 ). Method according to claim 2, characterized in that the soft component ( 11 ) on the surface of the integral foam structure ( 10 ) is sprayed on. Method according to one of claims 1 to 3, characterized in that the integral foam structure ( 10 ) partially with the soft component ( 11 ) is coated. Method according to one of claims 1 to 3, characterized in that the integral foam structure ( 10 ) completely with the soft component ( 11 ) is coated. Method according to one of claims 1 to 5, characterized in that a polyurethane coating component as a soft component ( 11 ) to form the coating ( 2 ) of the surface of the integral foam structure ( 10 ) is used. A method according to claim 6, characterized in that a polyurethane varnish is used, which is used to form the coating ( 2 ) of the integral foam structure ( 10 ) on the surface of the integral foam structure ( 10 ) is sprayed or into the mold cavity ( 6 ) of the molding tool ( 3 ) is injected. Method according to one of claims 1 to 7, characterized in that the coating ( 2 ) on the surface of the integral foam structure ( 10 ) is produced under a pressure of 40 to about 60 bar.

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