DE3610218A1 - Composite material and process for the production thereof - Google Patents

Abstract

A plurality of processes are already known for producing a metal coating on a plastic substrate material. Using these, however, only relatively thin metal layers can be applied to plastic, and only with limited adhesion of the metal layer to the plastic substrate material. Since such a coating does not always fulfil the high technical requirements, these disadvantages are to be compensated by the invention. In the composite material according to the invention, therefore, it is provided to apply the plastic substrate material subsequently directly onto the metal layer having a residual roughness.

Description

The invention relates to a composite material according to the The preamble of claim 1 and a method for manufacturing position of such a composite material according to the Preamble of claim 11.

Composite materials consist of a combination of several Materials where one material has the disadvantages of to compensate others. Such composites who therefore used in technology wherever be special demands on a component made from it be put. The present invention is about the connection of a plastic carrier material with metal, namely a surrounding surrounding the carrier material as  also in some areas, namely for example only one egg applied metal layer.

It is already known to have a metal coating Carrier material made of plastic or the like Form the carrier material, so on one to apply core formed from the carrier material. Problems arise primarily from the fact that usually for shaping in a corresponding Molded carrier material to be coated external surfaces still necessary for demolding Has release agent. To ensure good liability between the Plastic core material and retrofitting To allow metal, the surface must at least in the areas to be coated from the parting be exempted, without leaving any residue. To two corresponding methods are known, these are but on the one hand complex and on the other hand do not allow completely residue-free removal of the release agent from the carrier material.

In addition, the diverse ones have to be added later Application of a metal layer on a plastic carrier known material other, specific Disadvantage. For example, with a spray coating processing of the carrier material by liquefied metals just a physical integration of the through the liquid Metal just melt melted plastic leads to insufficient adhesion of the metal the plastic guaranteed. Become thin-walled parts with the help of this known method with Me tall coated, there is also the risk of Pardon. For high quality components This method is therefore unsuitable.

The invention is therefore based on the object To create composite material for high-quality components  and a reliable, inexpensive manufacturing specify procedures for such composite materials.

A composite material to solve this problem has the characterizing features of claim 1. Through the direct connection of the metal layer to the carrier material is achieved that release agent or other Fabrics cannot affect the quality of the adhesive. The residual roughness on the contact surface of the material layer to the carrier material ensures interlocking for the intensive mechanical connection of the individual Layers among themselves. A detachment of the metal layer of carrier material is avoided and very good peel and abrasion resistance guaranteed.

Particularly good adhesion between the carrier material and the metal layer is achieved when the latter on its side facing the carrier material open gaps between their side by side the metal grains into which the carrier material is pressed in so far that this the gap spaces or also fills cavities. Then a positive Ver bond the metal layer with the carrier material in the latter even in metal grains engages the undercuts formed in the metal layer.

A particularly advantageously designed according to the invention Composite material has a metal layer made up of several formed by adjacent metal grains Grain layers on. This creates a relatively thick me tallschicht that the vapor deposition of metal could not be achieved.

This leaves the composite according to the invention such areas of application are not closed, which has a greater thickness on the backing material brought metal layer require.  

The metal grains of the individual grain layers of the metal Layer expediently have a different Shape up. While the metal grains of the outside Grain layer of the composite material largely without intermediate spaces closely packed side by side gene, the remaining grain layers point to the carrier material towards increasingly larger gaps between their grain limit. The gap spaces preferably diverge towards the carrier material. This causes this to flow at the Formation of the connection between the metal layer and the carrier material easily into the gap spaces. On the one hand, this ensures a secure hold between the individual layers of the composite according to the invention created material and on the other hand a self-contained, smooth surface of the metal layer. Last but not least is the close relationship the metal grains lie in the outer grain layer prevents the carrier material from covering the entire Can penetrate metal layer, causing the metallic Surface could be interrupted by plastic, that is, the surface would be inhomogeneous.

According to a further proposal of the invention Carrier material and the metal layer or the metal layer both physically and chemically other connected, namely mechanically on the one hand the entry of the carrier material into the gap spaces of the Metal layer anchored to each other and form-fitting on the other hand, the carrier material with the grain boundaries of the Glued metal layer. By the latter Ver Adhesion differs from the composite according to the invention material of such materials in which the metal layer by electroplating, vapor deposition, but also egg spray coating is applied to the plastic.

The layer material can consist of all types of plastic, namely thermoplastics, thermosets and elastomers. Particularly good adhesion is created between the metal layer or layers and a two-component polyurethane foam as the carrier material. In this case, a secure connection to the metal is achieved through the still liquid compound, which migrates into the rough surface of the metal layer to the desired extent due to its particularly good flowability. In this way, the still liquid compound can be pressed into even the most remote places and thin gaps - even cavities - in the metal layer. The compound of a PU foam also creates a particularly good bond to the walls of the metal grains of the metal layer. Composites of this type have a plastic / metal adhesion that continues unabated even under extreme temperature shock loads. Detachment of the metal layer from the plastic in such a composite material cannot be determined even by cross-cutting tests.

A particularly advantageous layer material is created if a plastic foam un for the carrier material different density is used. At a such carrier material takes over the thickness distribution the cross section towards the middle. The boundary layers be then stand out from a continuously compacting Material with the formation of rind-like waiters areas with closed pores.

Such a layer material also offers an all dense surface on one side, if only one side with a Metal layer is provided.

It is not only conceivable that the invention All-round, two-sided or one-sided layer material has a metal layer, rather the metal layer also partially on one or opposite Sides of the layer material run to form a  Conductor system. Such a layer material is suitable also for printed circuit boards, mainly because of the despite the partial metal tracks remain smooth the surfaces. Several circuit boards can be used with it Arrange the smallest distance next to each other for education compact electronic components.

The method for achieving the object of the invention has the characterizing features of the claim on. Because first the metal layer on the corresponding part of a previously ver with release agent see form or mold half is applied to the surface of the metal layer pointing towards the inside of the mold the carrier material can be applied immediately without that they can come into contact with release agents beforehand or must. Both sides of a work to be produced be provided with a metal layer or the workpiece should even have a surrounding metal layer then both mold halves of the mold are whole or partially before the application of the carrier layer to be provided with an appropriate metal layer.

The liquid metal is expediently ent speaking surfaces of the mold half or mold halves sprayed and after cooling the liquid metal the carrier material applied. This can be done by itself known methods take place, namely for example Casting, reaction molding, injection molding, resin / fiber injection, Pressing, transfer molding or similar processes in art fabric deformation or forming. Depending on the procedure, the Base material for the carrier material before closing in a lower half of the mold are placed on the then the upper mold half before reacting to the plastic is put on. Alternatively, the one with the Me tallschicht or the metal layers provided form ge closed and then injected the plastic material will.  

It is particularly advantageous to apply the liquid metal the heated mold half or the heated mold halves to inject. This ensures that the metal the first grain layer is sufficient on the mold surface can flow away before it freezes. The surface of the This means that the metal layer is not only complete when required smooth, it also has a relatively high image accuracy that is required for structured mold surfaces chen is required. Heating up with liquid Metal to be provided with mold or mold half is made in each case but only to such an extent that on the one hand a sufficient ver flow the outside of the workpiece to be manufactured Grains of metal is guaranteed, but on the other hand the Solidify metal grains of other layers early enough that it is a relatively jagged, crater-like Form (internal) surface that provides enough grip for the carrier material to be subsequently applied bil det.

According to a further proposal of the invention, this is done Applying the metal layer to the mold or shape halves through one or more heated spray nozzles, by an appropriate handling device, For example, a robot can be guided. This allows extremely precise not only partial loading reach the form or the mold halves with a metal be provided layer, this also points also a targeted and uniform thickness. So can also be precision parts, such as Para bolspiegel, with the required accuracy put.

To the uniformity of the metal layer, but also that Reducing the time it takes to bring them up becomes an issue position of rotationally symmetrical workpieces gen, the mold or mold half during spraying to move the metal layer rotating. This can be done by  Commercially available devices are made, the turntable are ben-like. The corresponding form or Half of the mold is for this purpose on such Arrange device that the axis of rotation of the same with the axis of symmetry of the workpiece to be manufactured collapses.

An embodiment of the composite according to the invention material will be based on the drawings explained in more detail. Show it:

Fig. 1 shows a cross section through a closed and completely filled with a composite shape, and

Fig. 2 is a greatly enlarged cross section through the composite material according to the individual unit II of FIG. 1st

The present embodiment relates to a rotationally symmetrical workpiece 10 made of the composite material according to the invention with a plate-like shape. This already finished molded workpiece 10 is still in a closed mold 11 .

The mold 11 consists of two mold halves, namely a lower mold half 12 and an upper mold half 13 . The lower mold half 12 is provided with a recess to form the outer contour of the workpiece 10 and the upper mold half 13 with a protruding from a mold parting plane 14 protruding increase to form the inner contour of the workpiece. When the mold is closed, the elevation of the upper mold half 13 and the depression of the lower mold half 12 form a cavity corresponding to the contour of the workpiece 10 , namely a mold cavity 15 .

The mold cavity 15 forms in the form a base surface 16 for the workpiece 10 which runs parallel to the mold parting plane 14 and an adjoining collar 17 which runs around and slightly slopes outwards.

In the mold parting plane 14 , the shape 14 shown in this exemplary embodiment also has a circumferential heel elevation 18 on the upper mold half 13 and a correspondingly also formed circumferential recess 19 on the lower mold half 12 . The engaging recess 18 in the closed mold 19 serves on the one hand for guiding and centering the two mold halves 12 and 13 relative to one another and on the other hand as a lock for superfluous plastic material in the mold 11 .

The mold 11 can be made from the usual material used for mold construction, for example metal, plastic, synthetic resin, wood, etc.

In the present exemplary embodiment, the workpiece 10 has a continuous, approximately equally thick metal layer 20 on the outer sides of the base surface 16 and the collar 17 . This is backfilled with a carrier material made of a reaction plastic, namely an integral polyurethane foam 21 . The inside of the workpiece 10 is not provided with a metal layer 20 here. As a result, the outer surface of the integral PU foam 21 forms the inner contour of the workpiece 10 .

The structure of the composite material shown in this embodiment is clearly shown in FIG. 2. Accordingly, the composite material used to form the workpiece 10 is composed - from the outside inwards - by three layers, namely a release agent layer 22 , the metal layer 20 and the PU integral foam layer 21 . The release agent layer 22 does not necessarily have to be part of the composite material according to the invention; B. only very thin or be rich on the outside of the metal layer 20 before be available if the inside of the mold 11 is provided with a polytetrafluoroethylene coating as a permanent release agent. In addition, the release agent layer 22 can also be removed after the workpiece 10 has been removed from the mold, without the properties of the composite material being adversely affected thereby.

According to the invention, the special features of the composite material shown lie in the formation of the metal layer 20 . This consists of four superimposed grain layers 23 to 26 , which in turn each consist of a large number of metal grains 27 to 30 lying next to one another. Only the outer grain layer 23 , which forms the outer surface of the workpiece 10 , has directly adjacent metal grains 27th The latter are largely flat to form a smooth surface of the workpiece 10 on its outer surface facing the release agent 22 . By tightly arranged bevels of each sub-grains 27 have this Stalt in the outer grain layer 23 via an approximately rectangular Ge. In this way, there are practically no gap spaces between the grain boundaries of the metal grains 27 . The arranged above the outer grain layer 23 grain 24 to 26 have metal grains 28 to 30 with a completely different shape. These are namely by faster cooling or spraying onto a white base, namely the not yet completely cool th metal grains 27 of the outer grain layer 23 no longer pressed into a rectangular shape. As a result, the grain layers 24 to 26 are fissured more and more towards the center of the workpiece 10 . This fissure is due to a relatively irregular shape of the metal grains 28 to 30 , which form pronounced gap spaces 31 at their grain boundaries. Since the fissure of the grain layers 24 to 26 increases towards the inside of the workpiece, some of the gap spaces 21 run diverging to the carrier material.

As can be seen in FIG. 2, the gap spaces 31 are completely filled out by the PU integral foam 21 . Anchoring occurs between the PU integral foam layer 21 and the metal layer 20 which extends over all three of the embedded grain layers 24 to 26 . In contrast, the outer grain layer 23 which has practically no gap spaces in the present exemplary embodiment is not decomposed by PU integral foam 21 . As a result, a continuous metal layer is formed on the outside of the workpiece 10 , namely through the metal grains 27 which have flowed together or into one another the outer grain layer 23 .

The network structure of the carrier layer in FIG. 2 is intended to demonstrate the different density of the PU integral foam 21 in the workpiece 10 shown here. Accordingly, the PU integral foam material 21 has the lowest density in the middle of the workpiece 10 or the carrier material thereof. To the edges of the workpiece 10 , both to the uncoated inner surface of the workpiece 10 and to the metal layer 20 , the density of the PU integral foam 21 increases continuously. This creates a pore-free, rind-like surface on the uncoated inside of the workpiece 10 . Furthermore, the greater density in the edge regions of the PU integral foam 21 provides better physical and chemical anchoring to the grain layers 24 to 26 of the metal layer 20 , in that these are completely filled with liquid compound which is largely free of bubbles in the fully reacted state.

Alternatively, the separating agent layer 22 on the metal layer 20 of the workpiece 10 for finishing the metal layer 20 can be replaced by a lacquer layer or a coating of a nobler metal. In addition, it is possible to form the release agent layer so that it takes over the later function of a protective lacquer.

From a procedural point of view, the workpiece 10 is manufactured as follows:

When the mold is open, the metal layer 20 is first applied to the lower mold half 12 , which is either provided with a permanent release layer made of polytetrafluoroethylene or into which a release agent layer 22 has previously been injected. Since the workpiece 10 is a rotationally symmetrical part, the metal layer 20 is applied here with a lower mold half 12 rotating about the axis of symmetry of the workpiece 10 . The metal layer 20 is applied to the base 16 and the collar 17 of the lower mold half 12 by a heated metal spray nozzle which is specifically moved with the aid of a robot. The robot can so be controlled to be from the middle or from the edge of the workpiece 10, the half outer contour once the same from driving, whereby then as a result of rotation of the lower mold half 12, a uniform metal layer 20 fully constantly come about. But it is also conceivable to let the robot traverse the entire contour of the workpiece 10 several times with the metal spray nozzle. A grain layer would then occur every half of the contour. If the contour were traversed twice completely, a metal layer 20 with four grain layers 23 to 26 , one above the other, would emerge from FIG. 2.

After the metal layer 20 has cooled (preferably to room temperature), the final completion of the workpiece 10 can then take place. For this purpose, the mold 11 is closed and the remaining cavity of the mold cavity 15 through the PU integral foam material 21 completely filled, namely foamed. Depending on the manufacturing process used, the individual components of the PU integral foam 21 can be introduced into the lower mold half 12 in a suitable dosage before the mold 11 is closed. Alternatively, the individual components of the PU integral foam 21 can also be injected into the closed mold by suitable injection channels, both separated by two individual injection channels and premixed by a common injection channel.

• 10 workpiece
  11 shape
  12 lower mold half
  13 upper mold half
  14 mold parting level
  15 mold nest
  16 footprint
  17 collar
  18 increase
  19 deepening
  20 metal layer
  21 Integral polyurethane foam
  22 Release agent layer
  23 grain position (outer)
  24 grain position
  25 grain position
  26 grain position (inner)
  27 metal grain in 23
  28 metal grain in 24
  29 metal grain in 25
  30 metal grain in 26
  31 gap space

Claims (17)

1. Composite material with a non-metallic carrier material and at least one edge layer, preferably a metal layer, characterized in that the metal layer ( 20 ) having a roughness on its surface facing the carrier material is directly connected to the carrier material. 2. Composite material according to claim 1, characterized in that the carrier material fills the jagged surface of the metal layer ( 20 ), in particular voids and / or gaps ( 31 ) between adjacent metal grains ( 28..30 ) of the metal layer ( 20 ). 3. The composite material according to claim 1 and 2, since by in that the metal layer (20) comprises a plurality composed of juxtaposed metal grains (27..30) grain layers (23..26). 4. Composite material according to claim 3 and one or more of the further claims, characterized in that the metal grains ( 23 ) of the outer grain layer ( 23 ) nestle together without any noteworthy gap spaces between the grain boundaries to form a relatively smooth, unagitated outer surface. 5. Composite material according to claim 4 and one or more of the further claims, characterized in that the grain layers ( 24..26 ) located above the outer grain layer ( 23 ) are increasingly fissured towards the carrier material. 6. Composite material according to claim 4 and one or more of the further claims, characterized in that the carrier material fills the gap spaces ( 31 ) or voids of the grain layers ( 24..26 ) arranged above the outer grain layer ( 23 ). 7. Composite material according to claim 1 and one or more of the further claims, characterized in that the carrier material is anchored to the metal layer ( 20 ) and additionally glued. 8. Composite material according to claim 1 and one or more of the further claims, characterized records that the carrier material in some areas with the Metal layer is connected, especially for formation of certain cable runs on the carrier material. 9. Composite material according to claim 1 and one or more of the further claims, characterized in that the carrier material consists of plastic, preferably before a multi-component reaction foam (PU integral foam 21 ). 10. The composite material according to claim 9 and one or more of the further claims, characterized in that the carrier material has a different density, such that the outer regions, also facing the metal layer ( 20 ), have a greater density than an approximately central core. 11. Method of making a composite material from a carrier material and at least an edge layer, preferably a metal layer, where in succession the carrier material and the metal layer (s) are connected to each other, characterized net that the carrier material on the metal layer or is brought between the metal layers. 12. The method according to claim 11, characterized in that the metal layer (s) on the previously provided with a release agent surface (s) of one or both mold halves ( 12 or 13 ) of a mold ( 11 ) is applied and after cooling the Metal layer (s) the carrier material is brought into the previously or after closed form. 13. The method according to claim 11 or 12, characterized characterized in that the metal layer (s) by in the opened mold is made of sprayed liquid metal det. 14. The method according to claim 13 and one or more of the further claims, characterized in that the liquid metal is sprayed through at least one heatable spray nozzle onto the mold half (s) ( 12 or 13 ), the spray nozzle through a handling device, in particular a robot that is guided mechanically. 15. The method according to claim 11 and one or more of the further claims, characterized in that the mold half (s) to be coated with metal ( 12 or 13 ) is or are rotated during the spraying of the liquid metal, preferably for the manufacture position a rotationally symmetrical workpiece ( 10 ). 16. The method according to claim 15, characterized in that the mold half (s) ( 12 , 13 ) is rotated during the injection of the liquid metal about the axis of rotation of the workpiece ( 10 ) to be produced therein (are). 17. The method according to claim 13 and one or more of the further claims, characterized in that the metal is injected into the heated mold ( 11 ).