Patent Description:
Inlay parts of vehicles comprise a surface having a certain appearance and haptics that play a decisive role in the design and the perceived quality of the passenger compartment. Door panels often comprise a so-called map pocket, door inserts or a medaillion which are provided for example with a fleece, textile or felt-like decorative inlay.

In some cases this decorative inlay is inserted manually, whereby this inlay is typically made of several two-dimensional fleece blanks, which can be laminated with a double-sided adhesive tape on the back. The manufacturing process can be time consuming because of the difficulty to arrange several 2D-blanks onto an interior trim part having a three-dimensional shape such that they match exactly with the shapes and contours of the final interior trim part. Further, it is difficult at the beginning of a project when final geometries are still not fixed, to estimate the needed cycle time. In term of quality, the manual arrangement operation of more glued blanks matching exactly together generates a higher amount of scrap because of the risk to obtain overlapped or distanced blanks.

Alternatively, this decorative inlay can also be a 3D fleecy part, wherein the necessary adhesive layer is added by spraying dispersion or hot-melt glue. This alterative is on the contrary easier to plan, the cycle time is easier to predict, but is associated with more process steps and a higher level of automation, and thus with high machinery investment as spraying devices are fairly expensive.

<CIT> and <CIT> disclose vehicle parts that are fixed to other parts of the vehicle by means of an adhesive layer. Further examples of vehicle parts being fixed to other parts of the vehicle are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

It is one task of one embodiment of the present disclosure to present a process for manufacturing a three-dimensional inlay part for an interior trim part of a vehicle facilitating the assembly of the final interior trim part. Moreover, it is one task to present a process having a short predictable cycle time, while reducing investment costs, at the same time balancing the level of automation and the amount of investment, while keeping the amount of scraps small and increasing the repeatability and the quality of the process and of the final interior trim part.

Furthermore, an embodiment of the present disclosure has the objective to present a three-dimensional inlay part for an interior trim part of a vehicle that is obtained by such a process and an interior trim part comprising such a three-dimensional inlay part.

The task is solved by the features specified in claims <NUM>. Advantageous embodiments are the subject of the dependent claims.

According to one embodiment of the present disclosure a process for manufacturing a three-dimensional inlay part for an interior trim part of a vehicle, comprises the steps of.

Initially the thermo-formable main layer is usually a two-dimensional blank and thus flat and not curved. The adhesive layer and the releasable foil may be applied to the thermo-formable main layer by a supplier and thus well before it is formed by the forming unit. The releasable foil may also be considered as a removable foil.

When the three-dimensional inlay part is finished only the releasable foil has to be removed to connect the three-dimensional inlay part to a carrier, thereby forming a trim part of the vehicle. It is not necessary to spray a hot-melt glue or the like on the three-dimensional inlay part, thereby avoiding the risk of over-spraying which means that some areas are unintentionally provided with some of the hot melt glue. As no spraying operation is necessary the cost for the respective spraying devices can be avoided, thereby reducing the investment costs.

According to one alternative of the invention the thermo-formable main layer is made of a thermo-plastic material, wherein the process comprises the step of calibrating the thermo-formable main layer by means of a calibration unit before being inserted into the forming unit. Examples of a thermoplastic material are polypropylene (PP) and polyethylene-terephthalate (PET). In the calibration unit heat and pressure is applied to the thermo-formable main layer to reduce inner stress and air. Air may obstruct the heat transfer through the main layer. By removing the air the heat transfer through the main layer is homogenized and the heating of the main layer is accelerated. The calibration is conducted including the adhesive layer and the releasable foil.

According to one embodiment the step of forming the thermo-formable main layer into a three-dimensional inlay part comprises cooling of the thermo-formable main layer by means of the forming unit. As the main layer is heated during the calibration step it becomes soft enough to be formed into the three-dimensional inlay part. The cooling of the thermo-formable main layer upon forming facilitates the demolding thereby improving the dimensional accuracy of the inlay part.

In a further embodiment the thermo-formable main layer is made of a thermoplastic non-woven material. The non-woven material can be a fleece-material that offers a specific appearance and haptics. The non-woven material may comprise a mix of at least two kinds of fibers or elements with different melting temperatures or with elements that do not melt, such as flax fibers, The process temperature is chosen to melt one element or fiber while the other one keeps its characteristics to offer specific appearance and haptics. In particular when the three-dimensional inlay part is an interior inlay part the appearance and the haptics provided by the non-woven material increases the perceived quality of the passenger compartment of the vehicle.

In accordance with another embodiment the non-woven material may comprise bi-component fibers. Bi-component fibers have a core of a first thermoplastic material that is embedded into an outer layer of a second thermoplastic material. The first thermoplastic material has a melting point that is higher than the melding point of the second thermoplastic material. The temperature applied during the forming process is chosen between the two melting points. The outer layer is melting while the core of the bi-component fibers does not melt. A matrix of fibers glued to each other is created.

According to another alternative of the present invention.

Examples of a thermoset material are polyester and polyurethane (PU) or acrylate. It is noted that in case the thermo-formable main layer is made of a thermoset material a calibration step must not be conducted. The main layer made of a thermoset material is flexible enough to be formed into a three-dimensional inlay part without applying heat. However, to fix the three-dimensional shape the main layer has to be cured, for which purpose the latter is heated up at least to its curing temperature in the forming unit.

In a further embodiment a décor layer is applied on the décor side. The décor layer can be adjusted to the remaining design of the passenger compartment in a flexible way.

It is important that the adhesive layer can particularly easily be designed such that the adhesive layer maintains its adhesive properties after the forming process when and in particular after heat and pressure is applied. Moreover, adhesive layers used in the processes described herein need to be designed such that the adhesive layer does not become liquefied and migrates into the thermo-formable main layer. These properties may be for example be reached in case the adhesive layer is acrylic-, polyurethane- or polyolefine-based.

In accordance with another embodiment the releasable foil is stretchable. As noted earlier the releasable foil is applied to the adhesive layer well before the thermo-formable main layer including the adhesive layer and the releasable foil is inserted into the forming unit. In particular when convexly shaped sections are created by the forming process the stretchable properties of the releasable foil avoids that areas of the adhesive layer become uncovered due to releasable film delamination or breaking or the like. In these areas the adhesive layer could stick to the forming unit which then needs to be cleaned to avoid structural inaccuracies of the inlay part subsequently produced. Further dust or impurities may stick to the not protected areas and disturb the adhesion on the substrate.

Beyond that the stretchable adhesive layer enables to follow the elongations and distortions generated during the molding process to avoid tear down or wrinkling.

In a further embodiment the releasable foil is made of polyester, for example polyethylene-terephthalate (PET), of polytetrafluorethylene (PTFE) or of a silicone-based material. These materials are particularly suitable to provide the stretchable properties also under the conditions that prevail during the forming process.

The material of the adhesive layer and the releasable foil should be chosen such that after the forming process the releasable foil can be removed from the adhesive layer without the need to apply high forces. Moreover, the releasable foil should not break during removal from the adhesive layer.

A realization of the present disclosure is directed to a three-dimensional inlay part for an interior trim part of a vehicle obtained by a process according to one of the embodiment previously presented. The technical effects and advantages as discussed with regard to the present process equally apply to the inlay part. In particular the mounting process of the respective trim part of the vehicle is facilitated as only the releasable foil needs to be removed before gluing the three-dimensional inlay part to a carrier or to another part of the vehicle. Inlay parts may be used for map pockets in which the inlay parts are fastened to a main carrier of the door panel.

Another example of the present disclosure is directed to an interior trim part of a vehicle, comprising.

The main carrier may be a part of the door panel to which the inlay part is fastened. As noted, the releasable foil only has to be removed and after that the inlay part can be connected to the main carrier. The production is simplified and cost efficient as on the assembly line and nearby, no further machinery or equipment is needed.

The present disclosure is described in detail with reference to the drawings attached wherein.

<FIG> shows the relevant steps of a process according to a first embodiment for manufacturing a three-dimensional inlay part <NUM> of a vehicle <NUM> (see <FIG>). In the first step a thermo-formable main layer <NUM> made of a thermoplastic material and having a décor side <NUM> and a rear side <NUM> is provided which is a two-dimensional blank and thus almost flat and not noticeably curved. It is assumed that in <FIG> the décor side <NUM> is the upper side or upper surface and the rear side <NUM> is the lower side or lower surface of the main layer <NUM>. An adhesive layer <NUM> is applied on the rear side <NUM> and a releasable foil <NUM> is applied to the adhesive layer <NUM>. The respective steps may be conducted by a supplier and thus well before the subsequent steps.

In <FIG> the adhesive layer <NUM> and the releasable foil <NUM> completely cover the rear side <NUM>. It is, however, possible to only partially cover the décor side <NUM>, for example in the edge regions.

After that the thermo-formable main layer <NUM> including the adhesive layer <NUM> and the releasable foil <NUM> is transferred to a calibration unit <NUM> in which pressure and heat are applied. As visible from <FIG> a first temperature T<NUM> is applied on the décor side <NUM> and a second temperature T<NUM> is applied on the rear side <NUM>. The first temperature T<NUM> and the second temperature T<NUM> differ from each other. Usually the first Temperature T<NUM> is lower than the second temperature T<NUM>.

Internal stress and air are hereby removed to avoid that the air creates a resistance against the heat transfer inside the thermo-formable main layer <NUM>. The thermo-formable main layer <NUM> including the adhesive layer <NUM> and the releasable foil <NUM> is then transferred into a forming unit <NUM> where the thermo-formable main layer <NUM> is formed into a three-dimensional inlay part <NUM>.

As the thermo-formable main layer <NUM> is transferred immediately to the forming unit <NUM> the thermo-formable main layer <NUM> is still warm and soft enough to be formed into the three-dimensional inlay part <NUM> without damage. The forming unit <NUM> is equipped with a cooling element <NUM> to ensure the cooling of the three-dimensional inlay part to a temperature which allows the demolding without distortions.

As evident from <FIG> the forming unit <NUM> comprises an upper tool <NUM> and a lower tool <NUM> that are movable relative to each other. The thermo-formable main layer <NUM> including the adhesive layer <NUM> and the releasable foil <NUM> is inserted into the forming unit <NUM> when the forming unit <NUM> is in the open position in which the upper tool <NUM> and the lower tool <NUM> are at distance to each other. After that the forming unit <NUM> is closed by moving the upper tool <NUM> and the lower tool <NUM> towards each other. Thereby a certain pressure is applied to the thermo-formable main layer <NUM> including the adhesive layer <NUM> and the releasable foil <NUM> such that they are formed into the desired three-dimensional shape.

The upper tool <NUM> and the lower tool <NUM> may comprise cutting edges <NUM> or similar features like knives or blades such that parts of the thermo-formable main layer <NUM> including the adhesive layer <NUM> and the releasable foil <NUM> are cut. Thereby the dimensional accuracy can be increased compared to a forming process without cutting and/or a separate cutting step can be avoided.

After the forming process the forming unit <NUM> is opened and the now finished three-dimensional inlay part <NUM> is removed from the forming unit <NUM>. The cut parts <NUM>, in particular edge parts or off-cuts are removed. The finished three-dimensional inlay part <NUM> may then be transported, stacked and stored until it is mounted to its foreseen counterparts of the trim part <NUM> of a vehicle <NUM>. For that purpose the releasable foil <NUM> is removed from the adhesive layer <NUM>. The three-dimensional inlay part <NUM> can be fastened to a main carrier <NUM> (see <FIG>) or to another trim part <NUM> of a vehicle <NUM> via the adhesive layer <NUM>.

<FIG> shows the relevant steps of a process according to a second embodiment for manufacturing a three-dimensional inlay part <NUM> of a vehicle <NUM> (see <FIG>). In this case the thermo-formable main layer <NUM> is made of a thermoset material. Due to this difference no calibration step is conducted. To be able to form the thermo-formable main layer <NUM> into a three-dimensional inlay part <NUM> the forming unit <NUM> is equipped with a heating element <NUM>. The remaining steps are the same as explained for the process shown in <FIG>.

<FIG> show different embodiments of the three-dimensional inlay part <NUM>. For the sake of clarity the three-dimensional inlay part <NUM> is shown without any curvature.

In the first embodiment shown in <FIG> the three-dimensional inlay part <NUM><NUM> consists of the thermo-formable main layer <NUM>, the adhesive layer <NUM> applied to the thermo-formable main layer <NUM> and the releasable foil <NUM> applied to the adhesive layer <NUM>. The thermo-formable main layer <NUM> is made of a thermoplastic or thermoset material. The thermo-formable main layer <NUM> is geometrically stable at room temperature such that it maintains its shape after removal from the forming unit <NUM>.

The adhesive layer <NUM> may be acrylic-, polyurethane- or polyolefine-based. The releasable foil <NUM> may be made of thermoplastic polyester or of a silicone-based material. The releasable foil <NUM> and the adhesive layer <NUM> are provided with stretchable properties.

In the second embodiment of the three-dimensional inlay part <NUM><NUM> shown in <FIG> a décor layer <NUM> is applied to the thermo-formable main layer <NUM>. The remaining structure is the same as of the first embodiment of the three-dimensional inlay part <NUM><NUM>. The décor layer <NUM> may be fastened to the thermo-formable main layer <NUM> by needle-punching, thermo-laminating or gluing.

In <FIG> a third embodiment of the three-dimensional inlay part <NUM><NUM> is shown. <FIG> shows thermo-formable main layer <NUM> comprising the adhesive layer <NUM> and the releasable foil <NUM> before the forming process and <FIG> after the forming process. The thermo-formable main layer <NUM> is made of a thermo-plastic non-woven material <NUM> comprising thermoplastic fibers or elements, in this case a fleece material which may be made of polyethylenterephthalate (PET), for example PET-fibers or a mix of PET-fibers with different melting temperature.

Depending on the application the non-woven material <NUM> may also comprise some bi-component fibers <NUM> which comprise a first thermoplastic material <NUM>, e.g., PET in the core and an outer layer with a second thermoplastic material <NUM> having a lower melting point than the first thermoplastic material <NUM>. The temperature in the calibration device and the forming unit <NUM> is set above the melting point of the second thermoplastic material <NUM> but below the melting point of the first thermoplastic material <NUM>. Temperatures typically employed during the calibration and forming process are around <NUM>° and <NUM> for the rear side <NUM>.

<FIG> shows the finished three-dimensional inlay part <NUM><NUM> according to the third embodiment. Comparing <FIG> the compression of the non-woven material <NUM> during the calibration and forming process becomes evident. Due to the melting of the second material <NUM> the fibers <NUM> are glued to each other, thereby forming a comparatively stable matrix.

<FIG> show a side door <NUM> of a not further shown vehicle <NUM> in different mounting stages. <FIG> shows the side door <NUM> in the fully mounted state. The side door <NUM> comprises a door panel <NUM> which also acts as a main carrier <NUM> to or in which an inlay part <NUM> as described before may be fastened.

In the fully mounted state, i.e., with the inlay part fastened to the main carrier <NUM>, the door panel <NUM> constitutes an interior trim part <NUM> which forms a map pocket <NUM> together with a further trim part <NUM> which may also house parts of a loudspeaker grill <NUM>. The map pocket <NUM> is the hollow space encompassed by the door panel <NUM> and the further trim part <NUM>.

Other embodiments of an inlay part <NUM> are a door insert, a medaillion or an inlay for a dashboard.

<FIG> shows the side door <NUM> partially dismantled. In particular the further trim part <NUM> is removed. Moreover a three-dimensional inlay part <NUM> is removed but separately shown in <FIG>. In the shown embodiment the three-dimensional inlay part is made by the process as discussed above.

<FIG> shows a sectional view along a section plane defined in <FIG>. It is evident that the inlay part <NUM> is fastened to the main carrier <NUM> via the adhesive layer <NUM>. Before the fastening process the releasable foil <NUM> has been removed.

Claim 1:
Process for manufacturing a three-dimensional inlay part (<NUM>) for an interior trim part (<NUM>) of a vehicle (<NUM>), comprising the steps of
- providing a thermo-formable main layer (<NUM>) having a décor side (<NUM>) and a rear side (<NUM>), wherein
∘ an adhesive layer (<NUM>) is applied on the rear side (<NUM>), and
∘ a releasable foil (<NUM>) is applied on the adhesive layer (<NUM>),
- inserting the thermo-formable main layer (<NUM>) including the adhesive layer (<NUM>) and the releasable foil (<NUM>) into a forming unit (<NUM>),
- forming the thermo-formable main layer (<NUM>) into a three-dimensional inlay part (<NUM>) by applying pressure by means of the forming unit (<NUM>), and
- removing the three-dimensional inlay part (<NUM>) from the forming unit (<NUM>),
characterized in that
- the thermo-formable main layer (<NUM>) is made of a thermoplastic material and the process comprises the step of calibrating the thermo-formable main layer (<NUM>) including the releasable foil (<NUM>) by means of a calibration unit (<NUM>) before being inserted into the forming unit (<NUM>) or
- the thermo-formable main layer (<NUM>) is made of a thermoset material and the step of forming the thermo-formable main layer (<NUM>) into a three-dimensional inlay part (<NUM>) comprises heating of the thermo-formable main layer (<NUM>) by means of the forming unit (<NUM>), wherein the releasable foil (<NUM>) is removed from the adhesive layer (<NUM>) after the forming process.