DE102014224463A1 - Process for producing a multilayer molded body - Google Patents

Abstract

The invention relates to a method for producing a multilayer molded body (1). The shaped body consists of a carrier layer (2) made of plastic, a surface layer (3) forming the visible side of the shaped body (1) and designed as a plastic film, and an intermediate layer (4) arranged between the carrier layer (2) and the surface layer (3) plastic foam. The method is carried out in a tool consisting of three tool parts and comprises the following method steps:
a) forming a previously heated film section of the plastic film in a first tool part,
b) injecting a plastic into a cavity between a second tool part and a third tool part for producing the carrier layer (2),
c) foaming a cavity between the carrier layer (2) arranged in the second tool part and the foil section arranged in the first tool part for producing the intermediate layer (4) made of plastic foam,
d) removal of the multilayer molded body (1) from the tool parts.

Description

The invention relates to a method for producing a multilayer molded body, consisting of a carrier layer made of plastic, a surface layer forming the visible side of the shaped article and designed as a plastic film and an intermediate layer of a plastic foam arranged between the carrier layer and the surface layer.

Such multilayer moldings are preferably used in the automotive industry, in particular as a door sill, dashboard or as interior trim part. The shaped bodies usually consist of a plastic film which forms the visible side of the shaped body and has a three-dimensionally structured, embossed or grained or patterned surface. The underside of the plastic film is provided with a foam layer, which has a lower density than the film and thereby provides an attractive feel, in particular a soft feel of the surface of the molding. The carrier layer defines the geometric shape and the function of the shaped body. In this case, the required rigidity and stability of the molded body is ensured by the carrier layer. In addition to reinforcements and stiffeners, the carrier layer may also comprise fastening elements for fixing to corresponding structural components of the motor vehicle.

Using the example of a door sill, a currently commonly used production method will be explained in more detail below. First, a spraying of the support of the parapet in an injection mold. Before a film provided with a foam layer can be arranged on the support, the support is first activated by flooding and a hot melt known hot melt adhesive is applied to the foam backing of the film. Subsequently, the film is laminated with the foam layer in a laminating on the support. After punching or lasing the film arranged on the carrier and a folding of the film, the process is then completed and the door sill can be supplied for further use.

The DE 10 2004 023 582 A1 already describes a Hinterschäumanlage and a method for the production of plastic parts, in particular for motor vehicles. The plastic parts formed, for example, as dashboard, door trim, cover or panel consist of a foamed with a PU foam TPO film. To produce the plastic parts, the TPO film is first preheated in a Folienvorwärmstation and heated in a heating station to a temperature at which it can be easily deformed. Subsequently, the TPO film is pressed by a vertical movement of a forming die in a thermoforming mold and reshaped, wherein the film section is applied by means of vacuum to the thermoforming mold. Following this, the forming punch is moved out of the deep-drawing tool and a transfer punch with an integrated trimming unit is moved into the deep-drawing tool and separates the transformed film section from the rest of the TPO film. Before the transfer stamp moves back, the film section arranged and formed in the deep-drawing tool is subjected to pressure and pressed against the transfer punch. To ensure transfer, a vacuum is applied to the transfer stamp.

Subsequently, the deep-drawn film section is retracted and transferred by the transfer stamp in a foaming tool. Here, a foaming and curing station of the system has a turntable with a total of six foaming tools. After the film section has been positioned in a manual operation in the foaming tool and positively applied in the tool via vacuum, the transport of the foaming tool to the foaming station takes place in which the entry of the PU foam into the opened foaming tool takes place. After closing the foaming tool by a mold cover, the PU foam presses the film section against the surface of the foaming tool. After heating and curing of the foaming tool, the mold is opened and the finished plastic component is removed from the foaming tool.

Also the DE 10 2004 023 584 A1 describes a similar process for the production of plastic parts consisting of a foamed with a PU foam TPO film. By inserting a Vorformstempels in a negative mold of the plastic component exhibiting lower tool, the film is deformed and separated by an integrated cutter in the lower tool of the rest of the film. After moving out of the preform punch from the lower tool this is transported together with the film section to a foaming station. A mold die connected to a mold cap is retracted into the lower tool. After closing the tool, the area between the film section and the contour of the molding die is foam-backed with PU foam. The plant for the production of plastic parts also has a turntable with several sub-tools.

In the EP 2 263 857 A2 a method for producing a shaped body for the interior trim of motor vehicles is described, in which a sheet-like film body in a narbgebenden negative-drawing process in a component form is deep-drawn, which contains the desired Narbbild as a negative. Subsequently, the film is provided with a foam layer on the back. Furthermore, a trim part for the interior of a vehicle is described which consists of a support structure and a molded body applied thereto. With regard to the production of the existing of the support structure and the molding trim part no information is given.

In the DE 10 2010 063 451 A1 For example, a method for producing a lightweight component for automobile construction is described. Here, a natural fiber semi-finished product is first inserted into an injection mold and pressed into this to a molding and / or reshaped. Subsequently, in the same injection mold fastening elements and / or reinforcing structures are molded onto the molded part just produced, which form a mounting side of the lightweight component. Finally, a surface component, such as a thermoplastic elastomer or polyurethane, applied to the molding, which forms the visible side of the lightweight component. The method is preferably carried out in a hot plate injection molding machine, wherein the forming and pressing of the natural fiber semi-finished product and the injection molding of the reinforcing components takes place, while arranged between two mold halves insert of the injection molding machine forms a tool with a first mold half. After a pivoting of the insert together with the molded part produced by 180 °, the insert then forms together with the second mold half a tool in which then the surface component is applied to the molding.

The invention has for its object to provide an economical and improved process for the preparation of a multilayer molded body available.

This object is achieved by a method according to the features of claim 1. The subclaims relate to particularly expedient developments of the invention.

• a) Umformen eines zuvor erwärmten Folienabschnitts der Kunststofffolie in einem ersten Werkzeugteil,
• b) Einspritzen eines Kunststoffs in eine Kavität zwischen einem zweiten Werkzeugteil und einem dritten Werkzeugteil zur Herstellung der Trägerschicht,
• c) Ausschäumen einer Kavität zwischen der im zweiten Werkzeugteil angeordneten Trägerschicht und dem im ersten Werkzeugteil angeordneten Folienabschnitt zur Herstellung der Zwischenschicht aus Kunststoffschaum, wobei die Kavität sich durch eine Relativbewegung zwischen dem zweiten Werkzeugteil und dem ersten Werkzeugteil ausbildet,
• d) Entnahme des mehrschichtigen Formkörpers aus den Werkzeugteilen.

According to the invention, therefore, a method for producing a multilayer molded body is provided, which consists of a carrier layer of plastic, a visible side of the molded body forming and formed as a plastic film surface layer and disposed between the carrier layer and the surface layer intermediate layer of a plastic foam, the method following steps includes:

• a) forming a previously heated film section of the plastic film in a first tool part,
• b) injecting a plastic into a cavity between a second tool part and a third tool part for producing the carrier layer,
• c) foaming a cavity between the carrier layer arranged in the second tool part and the film section arranged in the first tool part for producing the intermediate layer of plastic foam, wherein the cavity is formed by a relative movement between the second tool part and the first tool part,
• d) removal of the multilayer molded body from the tool parts.

By means of the illustrated method, at least three processes, namely the forming of the film section, the injection molding of the carrier layer or the carrier structure and the rear foaming of the film section are produced in a single tool consisting of at least three tool parts. As a result, an economical and improved method for producing a multilayer molded body is provided. The intermediate products produced, such as, for example, the formed film or the sprayed carrier layer, can remain in the respective tool parts after their production, so that complex process steps for removing the intermediate products from the tool parts and a positionally correct positioning in another tool part are not required. The introduced in the space between the carrier layer and the film section plastic foam connects cohesively with both the carrier layer and with the film section, so that no hot melt adhesive (hot melt) is required for connection. In addition to the application of the hotmelt adhesive, other process steps such as the lapping and lamination of the carrier layer as well as the final repacking of the film, as used in the currently used processes for the production of such multilayer moldings, can be dispensed with. Due to the omission of process steps, the production time for the production of the molding is significantly reduced overall. The fact that only a single tool is used and a transport of the intermediate products is eliminated in other tools, there is a further reduction in both the investment costs for tools and the manufacturing cost per molded part.

The heating of the film before forming can take place in an upstream process step, for example in an oven. However, a further reduction of the production time is achieved in that the heating of the film section before the forming (step a)) takes place at a time at which the film section is already arranged in the first tool part. In this case, a heating can take place by means of a heater integrated in the first tool part. Alternatively, after the arrangement of the film section in the first tool part, a heating device can be directed from the side facing away from the first tool part to the film section, so that the film section is heated or heated to the temperature required for forming for example by laser radiation or infrared radiation.

A further advantageous embodiment of the present method is also achieved in that the forming of the film section in the first tool part (method step a)) is carried out by an applied negative pressure, wherein the film section applies as a result of the negative pressure to a negative mold of the shaped body arranged in the first tool part and thereby thermoforming is thermoformed. By using a negative pressure or a vacuum, the film section without a forming die, as used in the cited prior art, deep-drawn. In this way, therefore, both the forming die itself and the corresponding drive or control technology as well as the use of any necessary release agent, which is intended to prevent adhesion of the forming die to the heated film section, can be dispensed with.

In this case, it proves to be particularly expedient that the film section before forming (method step a)) is pressed sealingly against the first tool part by a functional component that is movable relative to the first tool part. The functional component, which is embodied, for example, as a sealing frame, is positioned after the arrangement of the film section in the first tool part by a handling element such that the film section is pressed sealingly against the first tool part in the edge sections. In this way, the formation of a vacuum or a vacuum is made possible and at the same time the film section is fixed in the first tool part and secured against undesired displacement during the forming process. After the forming of the film section, the functional component is then moved out of the first tool part again.

A further advantageous development of the method according to the invention is also provided in that the negative mold in the first tool part has a grain, which is formed by the application of the film section to the negative mold in the film section. As a result, a grain is also impressed into the film section simultaneously with the deep drawing or forming of the film section, which then forms the visible surface in the finished molded part or lining part.

According to the invention, it is further provided that after the production of the carrier layer (method step b)) the second tool part is moved together with the produced carrier layer relative to the first tool part such that between the carrier layer in the second tool part and the already formed film section in the first Tool part forms a cavity for the plastic foam of the intermediate layer. As a result, the intermediate products produced can remain in the respective tool parts, so that a removal and repositioning in another tool part is not required. In addition to a reduction in production time, this also minimizes the number of scrap or rework parts due to incorrectly positioned intermediate products.

In this case, it proves to be particularly expedient that the second tool part arranged between the first tool part and the third tool part after production of the carrier layer (method step b)) from a third position facing the third tool part about a pivot axis in a first tool part facing second position is pivoted. The second mold half is rotated after the injection process of the carrier layer by a pivoting movement by 180 °. As a result, the movement of the second tool part is realized in a particularly simple and reliable manner

The manufacturing process and the production time of the molded article are also optimized by providing the plastic film as a film web and separating the film section from the film web by means of a cutting or punching process. In this case, the film web is unwound for arranging a film section in the first tool part of a supply roll and after punching out a film section, the remaining film is then wound up on another roll again.

Furthermore, it is provided that, after the completion of the multilayer molded body, a trimming of the film section and / or of the shaped body takes place. This can be done after the removal of the molding from the tool parts or even if the molding is still arranged in one of the tool parts.

According to the invention, it is also provided that the plastic film consists of TPO and / or that the plastic foam consists of TPE and / or that the carrier layer consists of a thermoplastic material.

A film of TPO (thermoplastic elastomer based on olefin) is very ductile after heating to about 200 ° C and is therefore particularly well suited for the illustrated method. In addition, the TPO film is particularly scratch and abrasion resistant and has a pleasant feel, so that a uniform surface quality can be achieved.

The plastic foam made of TPE (thermoplastic elastomers) provides an attractive haptic, in particular a soft grip of the surface of the molded body. By loading the introduced plastic with an additional blowing agent, an open-pore foam can be made available.

The invention allows numerous embodiments. To further clarify its basic principle, one of them is shown in the drawing and will be described below. This shows in

1 a perspective view of a formed as a door parapet multilayer molding;

2 the structure of the multilayer molded body in a schematic representation;

3 a first tool part with an already transformed film section;

4 a second and third tool part with a manufactured carrier layer;

5 the first and second tool parts after foaming the intermediate layer;

6 a three tool parts existing tool with a pivotable second tool part, which is arranged in the first position;

7 this in 6 shown tool with a second position arranged in the second tool part.

1 shows a proposed as a door railing for a motor vehicle door multi-layer moldings 1 , which was prepared by the process according to the invention. As 2 can be seen, there is the multilayer molded body 1 from an injection-molded carrier layer 2 , one the visible side of the molding 1 forming and consisting of a TPO plastic film surface layer 3 and one between the carrier layer 2 and the surface layer 3 arranged intermediate layer 4 made of an open-pore TPE plastic foam.

The following is based on the 3 to 7 the inventive method for producing the in the 1 and 2 shown, multilayer molded body 1 explained in more detail.

For the production of the surface layer 3 is an in 3 illustrated first tool part 5 intended. After positioning a film section 6 from a TPO plastic film in the first tool part 5 becomes the previously heated film section 6 by an applied vacuum or a vacuum to a surface of a in the first tool part 5 integrated negative mold 7 of the molding 1 sucked in and thereby formed or deep-drawn. The foil section 6 lies after the deformation as in 3 shown on the negative mold 7 and initially remains in the first tool part 5 ,

The carrier layer 2 of the multilayer molding 1 is in a cavity 8th between a second tool part 9 and a third tool part 10 produced ( 4 ). For this plasticized by plastic in the second tool part 9 provided injection openings 11 into the cavity 8th injected. The preparation of the carrier layer 2 forming injection-molded part is preferably carried out simultaneously with the previously described deformation of the film section 6 in the first tool part 5 , However, it is also conceivable that the production of the carrier layer 2 temporally before or after the forming of the film section 6 in the first tool part 5 he follows.

Subsequently, the second tool half 9 together with the already at least partially cured carrier layer 2 such relative to the first tool part 5 , in which still the already formed film section 6 is arranged, moves, leaving a cavity 12 between the carrier layer 2 and the film section 6 or between the tool parts 5 . 9 formed. For the preparation of the intermediate layer 4 becomes the cavity 12 then foamed by a loaded with a leavening plastic or the carrier layer 2 and the film section 6 are backfoamed ( 5 ).

Subsequently, the produced multilayer molded body 1 then from the tool parts 5 . 9 are removed and cropped.

The 6 and 7 show one of the three tool parts 5 . 9 . 10 existing tool 13 for carrying out the described method for producing the multilayer molded body 1 , The second tool part 9 is about a pivot axis 14 rotatably mounted and can of the in 6 illustrated first position in the in 7 shown second position to be pivoted.

In a second tool part arranged in the first position 9 is by means of the second tool part 9 and the third tool part 10 the carrier layer 2 manufactured and by means of the first tool part 5 becomes the surface layer 3 forming film section 6 reshaped.

Subsequently, the second tool part 9 together with the carrier layer just produced 2 around the pivot axis 14 pivoted to the second position. In the second position forms between the carrier layer 2 in the second tool part 9 and the film section 6 in the first tool part 5 the cavity 12 which then forms the intermediate layer 4 is foamed with a plastic foam.

The second tool 9 can, as in 7 represented by dashed lines, be designed as a turning plate and two identically formed tool parts 9 . 9 ' exhibit. This can during the foaming of the cavity 12 already the next carrier layer 2 ' between the tool part 9 ' and the third tool part 10 getting produced.

LIST OF REFERENCE NUMBERS

1

 moldings

2

 backing

3

 surface layer

4

 interlayer

5

 first tool part

6

 film section

7

 negative form

8th

 cavity

9

 second tool part

10

 third tool part

11

 Injection port

12

 cavity

13

 Tool

14

 swivel axis

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

• DE 102004023582 A1 [0004]
• DE 102004023584 A1 [0006]
• EP 2263857 A2 [0007]
• DE 102010063451 A1 [0008]

Claims (10)

Method for producing a multilayer molded article ( 1 ), consisting of a carrier layer ( 2 ) made of plastic, one the visible side of the molding ( 1 ) and formed as a plastic film surface layer ( 3 ) and one between the carrier layer ( 2 ) and the surface layer ( 3 ) arranged intermediate layer ( 4 ) of a plastic foam, comprising the following method steps: a) forming a previously heated film section ( 6 ) of the plastic film in a first tool part ( 5 ), b) injecting a plastic into a cavity ( 8th ) between a second tool part ( 9 ) and a third tool part ( 10 ) for the production of the carrier layer ( 2 ), c) foaming a cavity ( 12 ) between the second tool part ( 9 ) arranged carrier layer ( 2 ) and in the first tool part ( 5 ) arranged film section ( 6 ) for the preparation of the intermediate layer ( 4 ) made of plastic foam, d) removal of the multilayer molded body ( 1 ) from the tool parts ( 5 . 9 ). A method according to claim 1, characterized in that the heating of the film section ( 6 ) before forming (method step a)) takes place at a time at which the film section ( 6 ) already in the first tool part ( 5 ) is arranged. Process according to claims 1 or 2, characterized in that the forming of the film section ( 6 ) in the first tool part ( 5 ) (Method step a)) by an applied negative pressure, wherein the film section ( 6 ) due to the negative pressure to one in the first tool part ( 5 ) arranged negative form ( 7 ) of the shaped body ( 1 ) is applied and deep-drawn while forming. Method according to at least one of the preceding claims, characterized in that the film section ( 6 ) before forming (method step a)) by a relative to the first tool part ( 5 ) movable functional component sealingly to the first tool part ( 5 ) is pressed. Method according to at least one of the preceding claims, characterized in that the negative mold ( 7 ) in the first tool part ( 5 ) has a grain, which by the application of the film section ( 6 ) to the negative mold ( 7 ) in the film section ( 6 ) maps. Method according to at least one of the preceding claims, characterized in that after the production of the carrier layer ( 2 ) (Method step b)) the second tool part ( 9 ) together with the carrier layer produced ( 2 ) relative to the first tool part ( 5 ) is moved, that between the carrier layer ( 2 ) in the second tool part ( 9 ) and the already formed film section ( 6 ) in the first tool part ( 5 ) a cavity ( 12 ) for the plastic foam of the intermediate layer ( 12 ) trains. Method according to at least one of the preceding claims, characterized in that between the first tool part ( 5 ) and the third tool part ( 10 ) arranged second tool part ( 9 ) after the production of the carrier layer ( 2 ) (Method step b)) of a third tool part ( 10 ) facing first position about a pivot axis ( 14 ) in a first tool part ( 5 ) facing the second position is pivoted. Method according to at least one of the preceding claims, characterized in that the plastic film is provided as a film web and the film section ( 6 ) is separated from the film web by a cutting or punching operation. Method according to at least one of the preceding claims, characterized in that after the completion of the multilayer molded body ( 1 ) a trimming of the film section ( 6 ) and / or the shaped body ( 1 ) he follows. Method according to at least one of the preceding claims, characterized in that the plastic film consists of TPO and / or that the plastic foam consists of TPE and / or that the carrier layer ( 2 ) consists of a thermoplastic material.

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