DE102015007923A1 - Method for producing a composite component for a vehicle, in particular a passenger car, and composite component - Google Patents

Abstract

The invention relates to a method for producing a composite component for a vehicle, in which at least one cover layer (24) comprising fibers is arranged as a first layer on a core layer (30) formed from a plastic foam as a second layer and pressed with the core layer (30). wherein during the pressing of the heated layers (24, 30) into a sandwich composite, variations in thickness of the cover layer (24) are absorbed by at least predominantly plastic deformation of the core layer (30).

Description

The invention relates to a method for producing a composite component for a vehicle, in particular a motor vehicle, according to the preamble of patent claim 1, as well as such a composite component according to the preamble of patent claim 12.

Such a composite component and a method for producing such a composite component, for example, already from the DE 10 2006 058 257 A1 to be known as known. In the method, at least one cover layer comprising fibers is arranged as a first layer on a core layer formed from a plastic foam as a second layer and pressed with the core layer.

In addition, composite components are known from the general state of the art and in particular from the production of standard vehicles. Such a composite component according to the prior art is in 1 shown in a schematic sectional view. The composite component has a carrier layer 10 which is a carrier of the composite component. Out 1 it can be seen that the carrier layer 10 Has fibers. For example, the carrier layer 10 formed of a fiber-reinforced plastic, wherein reinforcing fibers are embedded in a plastic matrix. The reinforcing fibers are, for example, glass fibers, wherein the plastic matrix may be polypropylene (PP). Furthermore, the composite component comprises at least one decorative layer 12 and one between the decorative layer 12 and the carrier layer disposed intermediate layer 14 , On one of the decorative layer 12 opposite side of the carrier layer 10 is on the carrier layer 10 another layer 16 arranged. The further layer 16 is with the carrier layer 10 connected, wherein the intermediate layer 14 both with the carrier layer 10 as well as with the decorative layer 12 connected is. The optional layer 16 is for example a decorative layer or a cover fleece.

For example, the intermediate layer 14 and / or the layer 16 made of a polyester fleece or formed as a foam layer. The decorative layer 12 is for example made of circular knit or formed as a film. For example, that comes in 1 shown composite component according to the prior art as interior trim part for use. Such composite components, in particular during the operation of the vehicle can be exposed to very high temperatures and - depending on the location - even a very high humidity. The composite component may be a visible component. This means that the composite component, in particular the decorative layer 12 , a visible side 18 with a surface 20 which, in the finished manufactured state of the vehicle, is visually perceptible by observers of the vehicle, in particular by occupants residing in the interior of the vehicle. Such visible components whose claim in addition to the mechanical properties, inter alia, in their appearance and feel, should meet the claim of a very good surface quality. Therefore, the quality of the surface should be 20 or the visible side 18 Do not change by applying temperature and humidity.

In the case of components made of flat, compressed fiber-reinforced fabrics, in particular hybrid nonwovens, there is a risk, with inhomogeneous distribution of the fibers or reinforcing fibers, that - as in US Pat 1 is shown - fiber ester 22 from the fibers of the carrier layer 10 form. These fiber esters 22 can adversely affect a surface of the carrier layer 10 visually noticeable by surface disturbances. These are also visible immediately after production, but clearly less noticeable than when exposed to high temperature and / or humidity. To cover such errors or surface defects comes, especially at high optical requirements, the intermediate layer 14 used, with the intermediate layer 14 for example, made of nonwoven fabric or formed as a foam layer. The intermediate layer 14 is used for laminating the surface defects. Such intermediate layers can hide surface irregularities. After exposure to heat and moisture, however, these bumps show up on the surface 20 ,

In 1 Here, the effect of heat influences on the composite component is shown. Due to high temperatures and humidity, the respective volume of the fiber ester decreases 22 to or the intermediate layer 14 relaxed and can no longer conceal existing deformations. The intermediate layer formed, for example, from polyester fleece 14 can not compensate for the extreme volume differences. The decorative layer formed, for example, of circular knitwear 12 then adapts to the shape of the intermediate layer 14 so that irreversible surface irregularities 20 arise. Alternatively or additionally, it may lead to an increase in volume of the fiber ester 22 by exposure to moisture, as the fiber ester 22 Save moisture. As a result, it comes - as in 1 exemplified by the influence of heat - to irreversible surface irregularities 20 , Because the surface 20 However, a certain optical and haptic claim must meet, this change is very unfavorable and should be avoided.

Object of the present invention is therefore to provide a method and a composite component of the type mentioned, by means of which a particularly advantageous surface can be created.

This object is achieved by a method having the features of claim 1 and by a composite component having the features of claim 12. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

In order to provide a method of the aforementioned type, by means of which a particularly advantageous surface of the composite component can be avoided, for example, unwanted surface changes of the composite component can be avoided, it is provided according to the invention that when pressing the heated layers to a sandwich composite thickness variations of the top layer at least predominantly plastic deformation of the core layer are absorbed. The invention is based in particular on the finding that the use of a layer of fibers, for example in nonwoven production, can not avoid the formation of fiber esters.

In order to avoid unwanted surface impairments, in particular a visible side of the composite component and in particular an optionally provided decorative layer, even when exposed to heat and / or moisture, thickness variations of the cover layer are substantially absorbed by predominantly plastic deformation of the core layer, for example, by unevenness or projections caused by the thickness variations which are raised opposite to the projections adjoining areas which are received in the core layer. For example, the projections are molded into the core layer during compression, in particular pressed. This means that the core layer during processing is able to plastically compensate for thickness variations of the cover layer.

In other words, the core layer and the cover layer form a sandwich composite or a layer structure, which is preferably heated before joining the layers. As a result, the core layer is softer or softened and particularly receptive, so that any existing fiber ester, in particular the cover layer, are pressed into the plastic foam of the core layer in a subsequent pressing operation. When cooling the layer structure, this state is frozen, so to speak. Thus, the proportion of fiber esters that are not at least in the plastic foam is reduced. In the case of fiber esters, which still project with at least one section out of the plastic foam, the expansion pressure resulting from the volume increase is particularly small in the direction of a side facing away from the core layer, for example in the direction of the optionally provided decorative layer.

In an advantageous embodiment, the cover layer has a higher compressive stiffness than the core layer. In particular, in processes such as sources or thermal processes, it is advantageous if the core layer has a lower rigidity, in particular pressure stiffness, than the cover layer. As a result, any unevenness of the cover layer also grow into the core layer. For example, due to the low resistance of the core layer, fiber esters expand toward the core layer as the fiber esters increase in volume due to heat and / or moisture. In comparison with a decorative layer provided on the cover layer, the core layer, due to its low compressive stiffness and / or greater thickness, especially in the processing process at elevated temperatures, will exhibit variations in thickness, which are for example caused by an increase in volume of the fiber esters and / or local inhomogeneities of the cover layer. a lower resistance, so that the fiber ester or thickness variations also extend in the direction of the core layer. Thus, significantly fewer changes can be seen on the optionally provided decorative layer, in particular on its surface arranged on the visible side, since the core layer absorbs the increase in volume of the fiber esters. At the same time fibers can be used for the cover layer, so that the cover layer can be formed as a fiber-reinforced cover layer.

Furthermore, it is possible with the composite component according to the invention to dispense with the use of polyester fleece for the cover layer, so that the composite component according to the invention can be produced in a particularly cost-effective manner. In addition, the weight of the composite component can be kept low, since in particular a low density of the core layer formed as a foam core can be realized.

In a particularly advantageous embodiment of the invention, the cover layer is formed of a fiber-reinforced plastic. As a result, a particularly high stability of the composite component can be realized in a low-weight manner, whereby undesired surface changes can be avoided.

It has proven to be particularly advantageous if the plastic of the cover layer is a thermoplastic. It has been found to be particularly advantageous if the thermoplastic of the cover layer is polypropylene (PP). The plastic of the cover layer is a matrix or a plastic matrix, in which the fibers are embedded as reinforcing fibers. Preferably, the fibers of the cover layer are glass fibers and / or natural fibers and / or carbon fibers or carbon fibers. In particular, the cover layer may be formed as a hybrid nonwoven fabric, organic sheet or Hybridge tissue. By means of this preferably thermoplastic cover layer, a particularly good retention of shape of the composite component can be ensured.

In a further advantageous embodiment, it is provided that thermoplastic resin foam of polyethylene terephthalate (PET) is formed. In other words, the core layer is preferably formed as a PET foam core, whereby any thickness variations, which are caused for example by the fibers or by the fibers of the cover layer formed fiber ester of the cover layer can be particularly well received.

PET is in a softened state at temperatures above 140 ° C and can thus be plastically deformed. Only when reaching the melting point above 250 ° C, the melting begins. While PP already melts at 160 ° C. This combination of materials is thus particularly advantageous because between 160 ° C and 250 ° C, the thermoplastic of the cover layer is melted and the core is plastically deformable, without that the foam structure is destroyed. This results in a large possible temperature range for the manufacturing process, which allows plastic deformation and also local thickness change of the core in the processing process and thus can compensate for inhomogeneities of the cover layers.

In a further embodiment of the invention, an adhesion promoter layer is arranged between the core layer and the cover layer.

A further embodiment is characterized in that a decorative layer is arranged on the cover layer. In this case, an intermediate layer is preferably arranged between the cover layer and the decorative layer.

Finally, it has proven to be particularly advantageous if the composite component is designed as an interior trim part. In particular, interior trim parts are usually exposed to high temperatures and high humidity, and due to the described structure of the composite component unwanted surface changes can be safely avoided.

The bonding of the cover layer to the core layer and / or the decorative layer can be effected by an enamel layer arranged between the cover layer and the core layer or between the cover layer and the decorative layer or by an additional layer arranged between the cover layer and the core layer or between the cover layer and the decorative layer be realized to the respective plastic of the core layer, the decorative layer and the cover layer and provided in particular reactive adhesive. The abovementioned melt layer is formed, for example, by at least one plastic, for example the cover layer and / or the core layer or the cover layer and / or the decorative layer, wherein this plastic is melted or melted so that the respective layers are joined together.

Finally, it has proven to be advantageous if after heating the layers (core layer and cover layer) cooling of the core layer and the cover layer is allowed, wherein at least the core layer and the cover layer are heated again after cooling and deformed and thereby pressed, for example the semifinished product is formed. The layers are cooled, for example, in a forming tool.

The optionally provided decorative layer is not heated, for example, but after heating and before forming on the then hot cover layer or a hot sandwich carrier comprising at least the core layer and the cover layer placed. As a result, the decorative layer is protected from the heat of heating.

It is also possible to provide the sandwich carrier comprising the hot core layer and the hot outer layer with the cold or hot decorative layer and to reform and cool in the hot state in the forming tool.

Particularly preferably, a semifinished product, in particular in the form of a flat material, is produced during the first pressing and heating of the layer structure. To form a component, the semifinished product is then reheated, whereby the core layer is soft again. By forming the semifinished product in the desired component further compression takes place.

Alternatively, a transportable semifinished product can be produced by means of a needling technique to simplify the production process. In this case, the fibers of the outer layers are through the core layer and optionally through the bonding layer, ie, melt layer or adhesive layer, guided by needles and connected thereto.

Basically, there are two variants: In a first of the variants, the layer structure is heated and a semifinished product is produced, for example with or without a decorative layer. Then a repeated heating and then a reshaping to the composite component. If a decorative layer is used, the decorative layer is laid, for example, before the forming process, that is to say arranged on the semifinished product or the sandwich carrier. In the second variant, the layer structure or sandwich composite is heated and the composite component is created. At least one optional decorative layer may be added prior to heating, but preferably this is done after heating and before pressing or forming.

In order to provide a composite component of the aforementioned type, in which undesirable surface changes can be significantly reduced, so that a particularly premature surface can be realized, it is inventively provided that thickness variations of the cover layer are accommodated by at least predominantly plastic deformation of the core layer. Advantageous embodiments of the composite component according to the invention are to be regarded as advantageous embodiments of the method according to the invention and vice versa.

The structure of the composite component makes it possible that in the manufacturing process thickness variations of the cover layer can be impressed substantially plastically into the foam of the core layer and during the processing process, a decorative layer or an optional intermediate layer is homogeneously pressurized. Thus, the decor facing side of the cover layer without unwanted ripples Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings; these show in:

1 a schematic sectional view through a composite component according to the prior art;

2 a schematic sectional view through a composite component with a formed of a plastic foam core layer, with at least one decorative layer and arranged between the decorative layer and the core layer and connected to the decorative layer and the core layer cover layer comprising fibers, wherein the core layer has a lower compressive stiffness than that Decorative layer has;

3 a further schematic sectional view through the composite component according to 2 after a heat influence; and

4 a further schematic sectional view through the composite component according to 2 after exposure to moisture.

While 1 a composite component according to the prior art shows show 2 to 4 in a respective schematic sectional view of a composite component for a vehicle, in which undesirable surface changes can be safely avoided even with strong temperature and / or humidity effects on the composite component.

According to the state of the art, in the case of special components in the interior area with visible surfaces, material composites are correspondingly provided 1 used. According to the prior art, for example, a polypropylene / glass fiber fleece or polypropylene / natural fiber fleece is used as a carrier material. By material inhomogeneities of the nonwoven form glass fiber esters, which in 1 as a fiber ester 22 are shown. The glass fibers contained in the glass fiber esters are not completely enclosed by the polypropylene matrix. Furthermore, due to inhomogeneity of the initial nonwoven fabric, different component thicknesses and / or component densities arise. To compensate for these thickness and density differences and unevenness in the surface of the nonwoven, for example, a polyester nonwoven or a foam pad is used as the intermediate layer 14 applied. The visible component surface is, for example, with a valuable textile or a film in the form of the decorative layer 12 concealed. However, this first requires the polyester fleece or the foam overlay with the decorative layer formed, for example, as a circular knitted fabric 12 be connected before this on the surface of the carrier layer 10 be applied. Due to high temperatures, the thickness of the carrier layer decreases 10 unevenly too. The polyester fleece is pressure-sensitive and can no longer compensate for the extreme volume differences and the circular knitted fabric (decorative layer 12 ) adapts you to the shape of the polyester fleece (interlayer 14 ) at. There are irreversible surface irregularities 20 ,

Moisture enters the composite component due to high humidity. This leads to an expansion of the fiber esters 22 that is to an increase in volume. Analogous to the reaction of the composite component to temperature influences, the polyester fleece (interlayer 14 ) do not compensate for the extreme volume difference, which in turn on the decorative layer 12 effect. This adapts to the shape of the intermediate layer 14 which, in turn, causes irreversible surface unevenness 20 arise.

2 shows now in a schematic sectional view of a composite component, in which the basis of 1 described surface unevenness 20 the decorative layer 12 can be significantly reduced. Also according to 2 is the decorative layer 12 formed for example from circular knit.

The composite component according to 2 includes a cover layer 24 and a layer in the form of a cover fleece 26 , wherein the cover layer 24 are formed from a fiber-reinforced plastic. In the plastic of the top layer 24 it is a thermoplastic, preferably polypropylene. In the plastic of the cover layer 24 fibers are embedded as reinforcing fibers, which may be glass fibers and / or natural fibers and / or carbon fibers or carbon fibers. Again, it may in the production of the respective cover layer 24 respectively 26 to fiber esters 28 or inhomogeneities and thus variations in thickness occur, which can be extended by temperature and / or moisture, in particular due to the small thickness of the cover layer 24 ,

The composite component according to 2 also has a core layer 30 from a thermoplastic foam on which the cover layer 24 and the cover fleece 26 are arranged. The cover layer 24 and the cover fleece 26 be in the production of the composite component together with the core layer 30 heated and with the core layer 30 pressed.

To now undesirable surface irregularities 20 To be avoided when pressing the heated core layer 30 and the topcoat 24 to a sandwich composite thickness variations at least the cover layer 24 received by at least predominantly plastic deformation of the core layer. For this purpose, the core layer 30 for example, a lower compressive stiffness than the cover layer 24 on. The cover layer 24 is between the core layer 30 and the decorative layer 12 arranged and with the decorative layer 12 and the core layer 30 connected. The cover fleece 26 is on one of the topcoat 24 opposite side of the core layer 30 arranged and with the core layer 30 connected. The respective connection of the cover layer 24 or of the cover fleece 26 to the core layer 30 takes place, for example, via a bonding layer which is between the core layer 30 and the topcoat 24 or between the core layer 30 and the cover fleece 26 is arranged. The connection of the cover layer 24 to the decorative layer 12 For example, also takes place via a between the cover layer 24 and the decorative layer 12 arranged binding layer. The core layer 30 is formed of a plastic foam, wherein the plastic foam is preferably a thermoplastic foam. The thermoplastic resin foam is preferably polyethylene terephthalate (PET).

The respective bonding layer is formed for example by an adhesive, in particular reactive adhesive, which in addition to the respective plastic of the core layer 30 , the top layer 24 and the decorative layer 12 is provided. Alternatively, it is conceivable that the respective bonding layer is formed by at least one plastic. This plastic can be one of the plastics of the core layer 30 and the topcoat 24 or the cover layer 24 and the decorative layer 12 or be provided in addition to these plastics.

The core layer 30 , the top layers 24 , the cover fleece 26 and the decorative layer 12 are respective layers through which a sandwich composite with thermoplastic foam core and thermoplastic fiber-reinforced cover layers 24 is formed, wherein the cover layer 24 For example, from hybrid nonwoven fabric, organic sheet or Hybridgewebe are formed. In contrast to the previously used material structure according to 1 must when using the sandwich composite according to 2 Surface irregularities can not be compensated by a polyester fleece, since the core layer 30 having slight asperities or fiber ester. Variations of the respective cover layer thickness due to inhomogeneous reinforcing fiber distribution are in the sandwich composite due to the significantly lower basis weight of the cover layer 24 not or hardly present or lead in the production of components to a plastic thickness change of the core layer 30 , which leads to a shape-faithful surface. Small variations of the respective cover layer thickness are optionally due to the thermoplastic foam core in the form of the core layer 30 balanced, as the fiber ester 28 or inhomogeneities in volume increase due to the low compressive stiffness of the core layer 30 at least partially, preferably completely in this and not completely in the decorative layer 12 Push. Therefore, in the sandwich composite no intermediate layer is required.

Nevertheless, no intermediate layer can be used, for example for optical and / or haptic purposes. If an intermediate layer is used, it is homogeneously loaded in the pressing process and shows no inhomogeneous relaxation after repeated heating. The production of the composite component according to 1 is more complicated than the production of the Composite component according to 2 because the circular knitted fabric on the visible side must first be connected to the polyester fleece before the decor can be applied.

Overall, can be by the composite component according to 2 create a higher surface quality, since due to the lower basis weight of the textile fabric in the form of the cover layer 24 respectively 26 a better surface finish can be achieved. In addition, the plastically deformable foam core compensates for inhomogeneities of the cover layer 24 , Furthermore, unwanted effects of temperature and humidity on the surface 20 be avoided. The surface quality is maintained both at high temperatures and at high humidity.

This is off 3 and 4 recognizable. 3 shows the composite component according to 2 after a heat influence. Out 3 it can be seen that the fiber ester 28 or in part, the inhomogeneities in heat influence in their volume increase, said volume increase through the core layer 30 can be recorded and thus compensated. Thus, no unevenness of the surface 20 ,

4 shows the composite component according to 2 after exposure to moisture, which occurs, for example, due to high humidity. The fiber esters 28 store moisture, which increases their respective volume. Again, the core layer 30 partially absorb the volume increase and thereby compensate, so that no unevenness of the surface 20 arise.

Compared to the composite component according to 1 Also, the weight of the composite component can be reduced because at least a major part of the carrier weight is replaced by a thermoplastic foam with significantly lower weight per unit area. If the intermediate layer is omitted, the manufacturing process is less complex. The circular knit fabric must first be connected to the intermediate layer for the standardized material. Since no intermediate layer as in the composite component according to 2 is required more, eliminates this process step. If the optional intermediate layer is used, it does not have a negative effect on the surface when heated again 20 out. In addition, a cost and time savings can be realized, since the cost of the polyester fleece and the connection of polyester fleece can be dispensed with the circular knit. In addition, process steps can be omitted, so that the composite component can be produced time and cost.

In the aforementioned sandwich composite, a textile fabric, in particular a hybrid nonwoven fabric, as a cover layer 24 with a significantly lower basis weight than the carrier layer 10 used. As a result, the resulting fiber esters or inhomogeneities are smaller and their expansion less subject to temperature influences. An increase in volume of the fiber esters 28 or inhomogeneities is through the core layer 30 balanced and there are significantly less changes in the surface 20 , Because the color of the topcoat 24 can be adjusted and adjusted via the plastic matrix and no surface unevenness 20 must be compensated, for example, designed as a circular knit decorative layer 12 directly on the material surface of the cover layer 24 be attached. The fiber esters 28 in sandwich composite are smaller than the composite component according to 1 and their extent at humidity influences less. Again, a use of a polyester fleece to compensate for unevenness is not necessary.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102006058257 A1 [0002]

Claims (12)

Method for producing a composite component for a vehicle, in which at least one fiber-comprising covering layer ( 24 ) as the first layer on a core layer formed from a plastic foam ( 30 ) arranged as a second layer and with the core layer ( 30 ) is pressed, characterized in that when pressing the heated layers ( 24 . 30 ) to a sandwich composite thickness variations of the top layer ( 24 ) by at least predominantly plastic deformation of the core layer ( 30 ). Method according to claim 1, characterized in that the cover layer ( 24 ) a higher compressive stiffness than the core layer ( 30 ) having. Method according to claim 1 or 2, characterized in that the cover layer ( 24 ) is formed of a fiber-reinforced plastic. A method according to claim 2, characterized in that the plastic of the cover layer ( 24 ) is a thermoplastic. A method according to claim 3, characterized in that the thermoplastic is polypropylene. Method according to one of the preceding claims, characterized in that the thermoplastic resin foam is formed from polyethylene terephthalate. Method according to one of the preceding claims, characterized in that between the core layer ( 30 ) and the cover layer ( 24 ) a bonding agent layer is arranged. Method according to one of the preceding claims, characterized in that on the cover layer ( 24 ) a decorative layer ( 12 ) is arranged. Method according to claim 8, characterized in that between the cover layer ( 24 ) and the decorative layer ( 12 ) an intermediate layer is arranged. Method according to one of the preceding claims, characterized in that the composite component is formed as an interior trim part. Method according to one of the preceding claims, characterized in that after the heating, cooling of the core layer ( 30 ) and the cover layer ( 24 ), at least core layer ( 30 ) and the top layer ( 24 ) are heated again after cooling and reshaped. Composite component for a vehicle, with at least one fiber-comprising cover layer ( 24 ) as a first layer, which on a core layer formed from a plastic foam ( 30 ) arranged as a second layer and with the core layer ( 30 ) is pressed, characterized in that thickness variations of the outer layer ( 24 ) by at least predominantly plastic deformation of the core layer ( 30 ) are included.

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