DE3814997A1 - Process for producing shaped parts from fibrous-material mats - Google Patents

Abstract

In the case of a process for processing mats of fibrous materials with a polymer binder to form spatially contoured shaped parts, the mat is formed into the final contour of the shaped part and pressed to the final density in a, possibly two-staged, pressing operation. To be able to form narrow and deep beads or grooves on such a shaped part, it is provided that the mat is pressed to almost the final density, at least in the region in which the beads or grooves of the later shaped part lie, and subsequently the beads or grooves are made during the course of the pressing operation by deep drawing.

Description

The invention relates to a method for processing Mats made of fibrous materials with plastic binders too spatial contoured molded parts, the contour of which is little, among other things at least a narrow, deep bead or gutter, the light of which Width is less than the thickness of the mat by the mat in at least one pressing operation corresponding to the Contour of the molded part formed and pressed to the final density becomes.

Methods of the aforementioned type are in a variety of Embodiments known. They are used from a relative perspective voluminous mats made of fibrous materials, if necessary in turn can be obtained from waste materials by addition of plastic binders and other additives spatially produce contoured molded parts, for example in automotive engineering for interior cladding, such as fittings boards, hat racks, door panels, etc., in furniture construction for Seat shells or the like and also for various other applications  purposes. Usually follows the Manufacture of the molded part, for example by painting, spraying, laminating Foils, carpets or the like. Furthermore, on the occasion of Packaging for automotive interior trim parts is often also various fasteners for inserting the ver attached part of clothing in the motor vehicle.

Especially in the area of automotive interior trim parts often spatially entangled contours in mostly asymmetrical desired training, for example in the range of Door panels, dashboards or the like. This requires relatively complicated forming processes, since mats of the named Type only have a very limited tensile strength and consequently not with conventional deep-drawing processes can be reshaped. So far you have mostly been through it helped that the molding process was done in two stages is by molding the mat in a first pressing process help, e.g. B. support fabrics, preformed and at the same time is pre-compressed to a certain extent, the contour of the Preforming tools such as the contour of the final molded part but with a smaller mold depth or mold height. The plastic binders used in such mats have thermoplastic and thermosetting components, the thermoplastic parts during the preforming process for melting brought to the preform after cooling at least the shape required for its transportation to give stability. The thermoset parts down against remain largely inactive. This preforming usually takes place using steam at approx. 100 degrees Celsius.

The preform is then subjected to a further pressing process subjected to being reshaped into the final contour and at the same time is compressed to the final value, whereby the thermoplastic parts of the plastic binder again  melted and the thermoset parts activated be that the final molded part form after cooling is stable and rigid. The final shaping usually happens with a temperature above 180 degrees Celsius.

With intricate contours and large depths of form or shape must at least increase the preforming with the leading press stamp, several of which form the upper tool, to be made in the individual mold sections ensure sufficient tightening of the mat material and to avoid cracks and shear. The final pressing however, you can usually use a one-piece tool respectively. To save preforming, it is still known to provide the mat with a fabric insert, which has a relatively high tensile strength. Such one Fabric gives the entire mat a much better one Tensile strength and it also acts as a kind of deep drawing help by better forming the mat into deep cones doors runs into it. Nevertheless, you can also use such a fabric-reinforced mat not very tight and create deep contours.

It is closed with the aforementioned processing methods Lich known, such areas on the molded part that are special are exposed to heavy loads after installation, e.g. B. attachment points etc., thereby in their strength to improve the mat in these areas to a higher final density is pressed, where appropriate also at these points a two-step process with a preceding pre-compression is provided.

To date, it is not possible with the known methods to produce such molded parts that are comparatively narrow and have deep beads or channels, as this is a real one Deep-drawing process would be necessary, which, however, as I said,  due to the properties of the mats to be processed cannot be realized. Such channels or beads are used, for example, for later assembly in addition, the end edges of laminated foils, carpet coverings or the like. to keep them clean, even in those areas where, for example, two materials different decor or structure butt to give a clean finish, given if, from a visual point of view, a kind of seam effect too achieve. This problem often arises, for example for door panels with inconsistent decor and uneven uniform surface structure, but it can also Provide seat covers. Usually, for example Backrest, the back with a plate-like shape part is completed with a bag-shaped cover made up in the backrest area in the front Usually made of textiles, often made of foil on the back. This type of covering is complicated and particular often arise in the seam area between textile and Film irregularities. It would therefore also be desirable here worth the film on the back and the fabric of the Front in a along the back contour of the back lean the circumferential gutter or bead.

The invention is therefore based on the object, a Ver propose driving with which it is possible to narrow and deep gutters or beads in a fiber mat trained molded part.

Based on the method mentioned at the beginning, this is Task solved in that the mat at least in the Area where the bead or gutter of the later shape partly lies and its areal extent that for the bead or channel corresponds to the necessary material requirements for a sufficient temperature to solidify the binder compressed to the final density range and then  the bead or groove during the pressing process through deep pull is molded.

The method according to the invention is any Kind of molded parts applicable whether they are in one stage process are immediately pressed into the final shape or first preforming and then final shaping takes place. So far, such narrow and deep beads or channels not to be molded because of the thickness of the mat both in the process with preforms, as well as in a one-step Press molds are too large to be drawn into narrow mold gaps to be able to. It would be crushed and sheared off. By pre-compacting at least these areas of the mat Except for the final density, the Final strength reached, which then also allows this Area of the mat into a narrow and deep contour move. Because of the already existing final density and the Binder strengthening is also the tensile strength of the mat materials significantly larger at this point, so that did traditionally deep-drawing processes and gutters or beads are formed with approximately vertical walls can be. Is the inventive method in the frame a two-stage molding process for the finished molded part used, the bead or groove is already on the occasion of the preforming. With a one-step pressing process on the other hand, the bead or gutter with its wall thickness already at final density due to low drag molded and then the rest of the area the mat, if necessary with trailing tools shaped and compacted. The temperature when compacting the The areas in question must be at least as high as: the binder and the fiber structure are sufficiently solidified but do not harden in order to immediately connect it enable deep drawing process.  

In the case of a one-step pressing process, it can be recommended len to use a mat with a fabric insert, as this the increased requirements for single-stage pressing holds. Such a one-step pressing process is special possible if the gutter or beading is a straight line Has course.

On the other hand, the bead or groove has a curved course on, it is advisable to pre-press the two steps increase by just putting the mat in a striped shape Area whose width is at least that for the deep-drawing process necessary material requirements corresponds to in the area the final density is pre-compressed, and then the other areas of the mat preformed and finally end be shaped.

This procedure is recommended because at a curved course of the gutter or corrugation Pulling in the mat can form folds and actually also need to train to meet the pulling needs to satisfy at this point. These creases will be then in the subsequent preforming of the surrounding areas the mat as well as the final shaping, so that the Finally, molded part has a perfect surface. For the rest, the use of a is also recommended here Fabric insert.

As already indicated, in the known methods the preforming is carried out at a temperature of approximately 100 degrees Celsius. In the method according to the invention, on the other hand, the compression takes place in the area of the channels or beads at a temperature of approximately 120 to 180 degrees Celsius in order to reach the area of the final density and to maintain it irreversibly. Also, as far as preforming is connected to this compression, this is done at a correspondingly elevated temperature, while the final shaping is carried out in a conventional one-stage or two-stage manner at a temperature of more than 180 degrees Celsius. In all cases, all processing steps should take place in immediate succession in order to meet the reaction times of the binders used - mostly synthetic resins - on the one hand, and on the other hand to ensure the necessary formability at every step.

The method according to the invention can be made from fiber fabric mats molded parts with deep beads or channels ask for storing foil or carpet coverings edges lying on the surface of the molded part are not. These foil or carpet edges will be inserted into the channels or beads, the molding pliable enough in the area of such beads or channels is to insert or stuff these edges too enable, but on the other hand the resilience is large is enough to then firmly enclose the edges. Consequently the method according to the invention offers the great advantage to manufacture the molded parts, the was previously not possible.

The invention is based on in the drawing shown embodiments described. In the drawing show:

Figure 1 is a plan view of a molded part in the design of a motor vehicle door panel.

FIG. 2 shows a section II II according to FIG. 1 on an enlarged scale;

Fig. 3-5 is a schematic representation of the process flow and

Fig. 6-8 each a plan view of an off the mat or the form of the respective process stages partly cut after completion of FIG. 3 to 5.

In Figs. 1 and 2, a door panel 1 is for a motor vehicle in top view and schematically shown in section. The door trim 1 has a carrier 2 which is formed by a molded part which has been produced from synthetic resin-bonded fiber materials by compression molding. The carrier 2 is provided at least on its visible side with a lamination 3 , which is formed for example from two different materials in the embodiment shown. For example, a plastic film lamination 4 is provided in the upper area of the door trim 1 , while the remaining area of the door trim 1 with a textile material 5 , z. B. carpet, is occupied. The lamination 3 is folded inwards on the outer contour edges of the carrier 2 , as can be seen at 6 . Furthermore, the lying on the visible side edges 7 of the foil lamination 4 and the textile lamination 5 are inserted into a groove 8 of the carrier 2 and stored there, so that in the plan view shown in FIG. 1, a clean end edge 9 is formed similar to a seam. Finally, the door panel 1 also has a crook 10 , which is formed by a recess 11 formed in the carrier 2 . Otherwise, the carrier 2, depending on the desired surface contour of the door trim 1 may have further increases or decreases.

In FIGS. 3 to 5 individual process steps in the manufacture of the carrier 2 forming the molded part are provided is. A mat 12 in the form of a loose but transportable composite of fiber materials serves as the starting material, with thermoplastic and thermosetting binders being embedded between the fibers. To create the deep and narrow bead 8 on the carrier 2 according to FIG. 2, the mat 12 is inserted between two heated mold plates 13 , 14 . When the mold plates 13 , 14 move together, the mat 12 is pressed in a strip-shaped section 15 into the region of the final density. The width of the section 15 corresponds approximately to twice the depth of the bead 8 ( Fig. 2). The remaining areas 16 , 17 of the mat remain largely undensified or are only slightly compressed. The intermediate product in the process stage according to FIG. 3 is shown in FIG. 6 in a partial plan view.

In a subsequent process step, the mat 12 compressed in section 15 is subjected to a preforming process ( FIG. 4). For this purpose, it is inserted between an upper preform 18 and a lower preform 19 . The two preforming tools 18 , 19 have a shape approximately corresponding to the finished molded part on the sides facing one another, but the final wall thickness on the molded part has not yet been reached. So 18 has the upper preforming tool before a salient contour 20 and the lower preforming mold 19 at the position opposite a trough-shaped structure Kon 21st Furthermore, the lower preforming tool 19 has a deep, narrow groove 22 , by means of which the bead 8 is produced on the carrier 2 according to FIG. 2. A stamp 23 with a corresponding contour, which is mounted so as to be movable and separate on the upper preforming tool 18 , serves as the counter-tool. When the preforming tools 18 , 19 are closed , the leading punch 23 first touches the compacted section 15 of the mat 12 , so that this section is drawn into the groove 22 on the lower preforming tool 19 by deep drawing. The mat can be tightened from the outside. Towards the end of this preforming process, the elevation 20 on the upper preforming tool 18 rests on the area 17 of the mat and forms this into the depression 21 . Finally, the further surfaces of the upper preforming tool 18 reach the mat surface and compress the remaining areas of the mat 12 .

At the end of the process stage according to FIG. 4, a preform 24 (see FIG. 7) is obtained which does not yet have the final wall thickness, but with the finished bead 25 - corresponding to the bead 8 in FIG. 2 - and with a recess 26 , for example to form a map pocket, a crook or the like. Is provided on a motor vehicle door clothing.

The preform is finally witnessed between two final molding tools 27 , 28 and pressed there to the final molded part 29 , the bead 25 hardly undergoing any change, while all other areas are still slightly deformed and pressed to the final density.

Claims (7)

1. Process for processing mats made of fibrous materials with plastic binders to form a spatially contoured shape, the contour of which includes, among other things, at least one narrow, deep bead or groove, the clear width of which is smaller than the thickness of the mat, by the mat in at least one pressing operation the contour of the molded part is reshaped and pressed to the final density, characterized in that the mat at least in the area in which the bead or groove of the later molded part lies and whose areal extent corresponds to the material required for the bead or groove, for a the consolidation of the binder compresses sufficient temperature to the region of the final density and then the bead or groove is formed on the occasion of the pressing process by deep drawing. 2. The method of claim 1, wherein the mat in one first pre-formed and compressed and in a second pressing process to the final contour  and pressed to final density, characterized net that the bead or gutter on the occasion of the front molding or the final forming by deep drawing be shaped. 3. The method according to claim 1 or 2, characterized records that with a rectilinear course of the bead or gutter the mat in an outline of the finished one Molded area in the area of Final density compacted, then the gutter or Bead formed by deep drawing and then the other areas of the compacted mat reshaped will. 4. The method according to claim 1 or 2, characterized records that with a curved course of the bead or gutter the mat only in a striped shape Area whose width is at least that for the low drawing process corresponds to the necessary material requirements, until it is compressed into the final density range, and that then the other areas of the mat can be formed in one or two stages. 5. The method according to any one of claims 1 to 4, characterized characterized in that a mat with a fabric location is used. 6. The method according to any one of claims 1 to 5, characterized characterized in that the compaction of the mat in the loading range of the bead or gutter at a temperature in the Range from 120 to 180 degrees Celsius, preforming at the same temperature and the final shaping at more than 180 degrees Celsius.   7. The method according to any one of claims 1 to 6, characterized characterized in that the compression in the area of Bead or gutter, the one provided Preforming and final shaping in the immediate time be carried out.