FUNCTIONAL ELEMENT FOR ATTACHMENT TO A PLASTIC COMPONENT AND A COMPONENT ASSEMBLY

Abstract

A functional element of metal having a flange of larger diameter from an attachment surface and a centering section arranged inside the attachment surface and extending away from the flange, characterized in that an adhesive is arranged around the cylindrical section and adjacent to the attachment surface.

Claims

1. A functional element (10) of metal having a flange (14) of larger diameter forming an attachment surface (12) and a centering section (16) arranged inside the attachment surface and extending away from the flange, wherein an adhesive (30) is arranged around the centering section (16) and adjacent to the attachment surface (12) and wherein at least one recess (38) is formed in at least one of the flange (14) and the centering section (16) to take up excess adhesive, the recess (38) being a ring recess which is arranged radially inside the attachment surface as an axial groove in the flange (14).

2. A functional element (10) in accordance with claim 1, wherein the adhesive (30) has the shape of a ring (30), one side (35) of which is designed for attachment to the functional element (10) and the second side (33) of which is designed for attachment to a plastic component.

3. A functional element (10) in accordance with claim 2, wherein the adhesive ring (30) is realized as one of a transfer adhesive and a two-sided adhesive element.

4. A functional element (10) in accordance with claim 1, wherein the adhesive is an adhesive which hardens under pressure.

5. A functional element (10) in accordance with claim 1, wherein the adhesive is present in the form of an adhesive ring (30) with a rectangular cross-section.

6. A functional element (10) in accordance with claim 1, wherein the adhesive (30) has at least one component present in at least one of micro-capsules and nano-capsules and adheres to the functional element at at least one of the attachment surface (12) and the centering section (16) by means of a bonding agent which holds the capsules together and to the functional element prior to the attachment to a component and prior to bursting of the micro-capsules or nano-capsules containing at least one component of the adhesive.

7. A functional element (10) in accordance with claim 1, wherein the centering section (16) has a shape in cross section which is one of: a round circular shape, a ring shaped, a polygonal shape, a grooved shape and a ribbed shape.

8. A functional element (10) in accordance with claim 1, wherein the attachment surface (12) is arranged radially inside a contact surface (40) and is set back relative to the latter in an axial direction (64) of the centering section (16).

9. A functional element (10) in accordance with claim 8, wherein the contact surface (40) forms an outer ring surface and the attachment surface (12) forms an inner ring surface.

10. A functional element (10) in accordance with claim 1, wherein it is one of the following elements: a nut element, a bolt element, a hollow element, an element having a cylindrical projection for receiving one of a shaft clip and a bearing sleeve.

11. A functional element (10) in accordance with claim 1, wherein it is provided in conjunction with a plurality of like functional elements (10), with the functional elements being arranged in one row or in a plurality of rows in a flexible carrier band (31; 102) and being capable of being buttoned out of the carrier band by bending over of the carrier band.

12. A functional element (10) in accordance with claim 11, wherein the carrier band (31) is formed at its surface confronting the functional elements (10) as a protective film for the adhesive or adhesive ring (30).

13. A functional element (10) of metal having a flange (14) of larger diameter forming an attachment surface (12) and a centering section (16) arranged inside the attachment surface and extending away from the flange, wherein an adhesive (30) is arranged around the centering section (16) and adjacent to the attachment surface (12) and wherein at least one recess (38) is formed in at least one of the flange (14) and the centering section (16) to take up excess adhesive, the recess (38) being a ring recess which is arranged as a radial groove in the centering section (16).

14. A functional element (10) in accordance with claim 1, wherein the adhesive (30) has the shape of a ring (30), one side (35) of which is designed for attachment to the functional element (10) and the second side (33) of which is designed for attachment to a plastic component

15. A functional element (10) in accordance with claim 1, wherein the adhesive is an adhesive which hardens under pressure.

16. A functional element (10) in accordance with claim 1, wherein the adhesive (30) has at least one component present in at least one of micro-capsules and nano-capsules and adheres to the functional element at at least one of the attachment surface (12) and the centering section (16) by means of a bonding agent which holds the capsules together and to the functional element prior to the attachment to a component and prior to bursting of the micro-capsules or nano-capsules containing at least one component of the adhesive.

17. A functional element (10) in accordance with claim 1, wherein the attachment surface (12) is arranged radially inside a contact surface (40) and is set back relative to the latter in an axial direction (64) of the centering section (16).

18. A component assembly comprising a functional element of metal and a component (56) consisting of plastic, the functional element having a flange (14) of larger diameter forming an attachment surface (12) and a centering section (16) arranged inside the attachment surface and extending away from the flange, wherein an adhesive (30) is arranged around the centering section (16) and adjacent to the attachment surface (12), wherein the centering section (16) extends into a hole (58) of the component (56) and wherein the adhesive (30) forms an adhesive connection between the attachment surface (12) and the surface of the component (56) lying opposite to it wherein the functional element has at least one recess (38) formed in at least one of the flange (14) and the centering section (16), the recess (38) being at least partly filled with excess adhesive, the recess (38) being a ring recess which is arranged in at least one of the following ways: radially inside the attachment surface as an axial groove in the flange (14), and as a radial groove in the centering section (16).

19. A component assembly in accordance with claim 18, wherein the functional element is formed with the attachment surface (12) arranged radially inside a contact surface (40) and the attachment surface is set back relative to the contact surface (40) in an axial direction (64) of the centering section (16) with the contact surface (40) lying directly at the surface of the component (56).

20. A component assembly in accordance with claim 19 in which the surface of the component facing the attachment surface (12) has a ring step (86) with a height which is smaller than the amount by which the attachment surface is set back relative to the contact surface.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0031] The invention will subsequently be explained in more detail with reference to embodiments and to the drawings which show:

[0032] FIGS. 1A-1C a functional element in accordance with the invention in a half plan view from below (FIG. 1A) in a half sectioned side view (FIG. 1B) with an enlarged representation of the circled region of FIG. 1B (FIG. 1C),

[0033] FIG. 1D, 1E a schematic representation of the attachment of the adhesive ring to the element of FIGS. 1A to 1C (FIG. 1D) and an enlarged perspective illustration of the circled region of FIG. 1D (FIG. 1E),

[0034] FIGS. 2A-2C the attachment of the functional element of FIGS. 1A to 1C to a relatively thin component using a die button, with FIG. 2A showing the starting situation and FIG. 2B showing the finished component assembly, while the FIG. 2C shows an enlarged representation of the circled region of FIG. 2B,

[0035] FIGS. 3A, 3B a further embodiment in accordance with the invention similar to FIGS. 2A-2C,

[0036] FIG. 4A-4C drawings similar to FIGS. 2A to 2C but of a slightly modified embodiment

[0037] FIGS. 5A, 5B a modified component assembly in accordance with the invention with the FIG. 5B showing the circled region of FIG. 5A to an enlarged scale,

[0038] FIG. 6 a schematic representation of the use of a carrier band in order to hold, to transport and to release a row of functional elements, and

[0039] FIG. 7 a centering bolt in accordance with the initially named German patent application which is however modified in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The FIGS. 1A-1C show a functional element 10 of metal having a flange 14 of large diameter D1 forming an attachment surface 12 and having a centering section 16 of smaller diameter D2 arranged within the attachment surface 12 and extending away from the flange.

[0041] Above the flange 14 and readily visible in FIG. 1B there is a cylindrical projection 18 which merges via a radius into an upper side of the flange in FIG. 1B. The ring surface 20 which arises in this way forms a pressing surface which, on the attachment of the functional element 10 to a plastic component, serves for the application of the required pressing force. Through the provision of this ring surface 20 the thread 22 of the functional element 10 which is here formed as a nut element is protected against deformation by the pressing force. At the same time the axial height of the counter-levered flange part 14 can be reduced to the required dimension and hereby the weight of the functional element likewise reduced.

[0042] One can see that the outer peripheral surface 24 of the functional element has a rounded ball-like shape which arises automatically during the manufacture of the functional element in a cold heading process. This rounded shape is of advantage because, on the one hand, it saves weight and, on the other hand, also forms a gentle transition from the axially parallel region 26 of the outer peripheral surface of the flange into the lower side of the flange. The rounded transition 28 avoids undesired notches at the surface of the plastic component.

[0043] An adhesive 30 is arranged around the centering section 16 and adjacent to the region of the lower side of the flange 14 here referred as the attachment surface 12. As can be seen from the FIGS. 1B and 1C the adhesive is secured in the form of a ring to the functional element 10.

[0044] Furthermore one sees, in particular from FIGS. 1B and 1C that the adhesive ring 30 is at least substantially rectangular when sectioned in a longitudinal plane including the longitudinal axis of the functional element.

[0045] The adhesive ring 30 has a longer limb 32 arranged adjacent to the attachment surface and a shorter limb 34 arranged adjacent to the centering section, with the longer limb 32 and the shorter limb 34 preferably forming a right angle between them.

[0046] A recess 38 which takes up excess adhesive is provided in this embodiment in the flange 14. A recess can alternative or additionally be formed in the centering section (not shown).

[0047] The recess 38 is, as shown, a ring recess which is formed radially outside of the attachment surface as an axial groove in the flange 14. Instead of this, the ring recess could also be arranged as a radio groove in the centering section 16 or radially inside the attachment surface or interrupting the latter.

[0048] Furthermore, the possibility exists, instead of providing a ring recess 38 (or as a supplement thereto-not shown) to provide a plurality of recesses which are arranged inside the attachment surface and around the longitudinal axis of the functional element, for example recesses in the form of radially extending grooves.

[0049] In the FIGS. 1A to 1C the centering section is circularly round in cross-section and of ring-like form. It could however, if required, also have a polygonal or a grooved or ribbed shape.

[0050] One can see, in particular from FIG. 1B, that the attachment surface 28 is arranged radially inside a ring-like contact surface 40 and is set back relative to the later in the axial direction of the centering section 16 by an amount h, which amounts for example to about 0.1 mm. The contact surface 40 forms an outer ring surface and the attachment surface 28 forms an internal ring surface, with the ring recess 38 which accommodates the excess adhesive being provided between the contact surface 40 and the attachment surface 28.

[0051] The function element 10 is formed in FIGS. 1A-1C as a nut element, it could however equally be formed as a bolt element as is shown in FIG. 7.

[0052] It will be understood that the previous description of FIGS. 1A to 1C also applies in transferred sense for the bolt element in accordance with FIG. 7 in which the same reference numerals are used and have the same significance.

[0053] Furthermore, the functional element could be formed as a hollow element or as an element with a cylindrical projection for receiving a shaft or a clip or a bearing sleeve (not shown).

[0054] The design of the adhesive ring 30 will now be described with reference to FIGS. 1D and 1E. Adhesive bands are known which consists of carrier materials, for example plastic films or plastic foams, paper, metal foils or textile fabrics and which are coated on one side or on both sides with pressure sensitive adhesive. They are frequently also referred to as a double-sided adhesive tape. In industrial manufacture, so called transfer adhesive bands are also used: these are carrier-free thin pressure sensitive adhesive films which can be covered prior to processing on both sides with waxed or siliconized protective paper. Such transfer adhesive bands or adhesives bands can for example be obtained from the company 3M. In the following transfer adhesive bands and double-sided adhesive bands will be collectively referred to as adhesive bands.

[0055] Such adhesive bands are frequently delivered by a supplier in the form of a coil of the actual adhesive in strip shape or label shape and is or are arranged on a strip of a protected film. By the coiling of the protective film with the adhesive strip arranged thereon, or with the labels arranged thereon, the protective film comes into contact with both sides of an adhesive or of the labels so that two protective films are not required.

[0056] It is known in the automotive industry to use adhesive bands for joining or for attaching vehicle components, for example trim strips, mirrors and emblems are adhesively attached using adhesive bands and they are also used in seat heating systems and electronic components.

[0057] In the present case, as shown in FIGS. 1D and 1E, adhesive rings 30 are used which are punched out appropriately for the shape of the fastener elements that are used, for example in the form of rings, such as an adhesive ring 30 of FIGS. 1A to 1C. The so punched out adhesive band pieces can be subsequently separated from the protective film 29 of FIG. 1D by a suitable transfer device which is symbolized by the arrows P. In this arrangement, the strip 29 is moved in the direction of the arrow R away from the coil (not shown), so that the transfer device can pick up or engage the individual rings 30. They are then placed one after the other by the transfer device P onto a pre-pierced carrier band 31, which in this embodiment is moved in the direction of the arrow S. The carrier band 31 consists of a durable material such as for example a strip of plastic or a fabric strip which can also serve as a protective film or be covered by the protective film. The transfer takes place in this example in such a way that a first (lower) side 33 of the adhesive band ring 30 is connected to the carrier band 31 and a second (upper) free side 35 of the adhesive band ring 30 is freely accessible from above. A functional element 10 is then firmly connected to the free side 35 of the adhesive band ring 30. This can take place through a further transfer device which place the functional element 10 one after the other onto the respective adhesive tape rings 30 as is for example schematically shown by the arrow T. In this connection the functional element 10 can be guided in an ordered manner in the arrow direction U along a suitable guide 37 to the corresponding transfer device (T). The upper side 35 of the adhesive ring 30 then sticks to the attachment surface 12 of the respective functional element 10. Thereafter, the carrier band 31 is guided at a selected point in time, at which the functional element 10 are to be connected with components, into a processing machine in which the functional elements 10 and corresponding plastic parts are processed into a component assembly which will be later described in more detail in connection with FIG. 5.

[0058] The FIG. 2A now shows the functional element 10 of FIGS. 1A to 1C in accordance with the invention arranged within a holder 50 which can for example be formed as a setting head. Such setting heads are extremely well known in the field of fastener elements for use with the sheet metal parts and do not need to be explained further here.

[0059] One can see that the holder 50 of the setting head has a lower end face 52 and also a cutout 54 corresponding to the external shape of the functional element 10, with the cutout being so dimensioned that the contact surface 40 of the functional element 10 lies in a plane with the lower side 52 of the holder 50. Beneath the functional element 10 is located a plastic component which is supported on a die button 60. A hole 58 is present in the plastic component 56 with the margin of the hole defining an internal diameter which corresponds to the external diameter of a central projection 62 of the die button 60. This diameter likewise corresponds to the outer diameter D2 of the centering section 16 of the functional element 10.

[0060] One can further see from FIG. 2A that the central projection 62 of the die button, the hole in the plastic component 56 and also the centering section 16 of the functional element 10 have a common central longitudinal axis 64. Thus the plastic component 56 also lies in this stadium concentric to the centering section 16 of the functional element. Furthermore, one can see from FIG. 2A that the central projection 62 of the die button in a lower region 66 of the central projection 62 serves for the centering of the plastic component 56 and only in an upper region for the centering of the functional element 10. Above this lower ring-like region 66 there is located a ring-like cutout 68 of the central post 62 which has a form which deviates slightly from the shape of the lower region 70 of the centering section 16 so that this region of the centering section 16 is slightly compressed, slightly reshaped and fractionally dilated when the holder or the setting head 50 is pressed against the ring-like driven surface 20 of the functional element 10 in the direction of the arrow F.

[0061] One can imagine the arrangement in accordance with FIG. 2A such that the die button 60 is centered in the lower tool of a press while the holder 50 or the setting head is arranged either in the intermediate plate of the press (if present) or in an upper tool of the press. On closing of the press, the holder 50 is thus moved towards the plastic component 56 and the die button 60, with the upper side 72 of the plastic component in the region around the hole 58 being pressed against the adhesive ring and also with the internal margin of the hole 58 scraping adhesive from the centering section 16 and hereby subjecting the adhesive ring 30 to pressure so that the components of the adhesive react together and are set under pressure and the adhesive cures. When using an adhesive with micro-encapsulated or nano-encapsulated components the capsules burst under the applied pressure and allow the corresponding components to enter into an intimate mixture with one another whereby the chemical curing reaction is triggered.

[0062] In this respect the accurate fitted shape of the outer surface of the centering section 16 and the margin of the hole of the opening or the aperture 58 of the plastic component ensure that no adhesive or only a very small quantity of adhesive runs past the centering section 16 i.e. this region is well sealed so that the adhesive is set under pressure in the now rectangular space 74 between the upper side of the plastic component and the attachment surface 38 of the functional element 10 and cures there, as is shown in FIGS. 2B and 2C. In this connection excess adhesive enters into the ring recess 38 around the attachment surface 38. one sees further from FIGS. 2B and 2C that the contact surface 40 of the functional element 10 likewise sealingly lies against the surface 70 of the plastic component 56 but does not however press into this or only to a small degree. Thus the axial height h in accordance with FIG. 1B also determines the axial thickness of the hardened or cured quantity of adhesive 76 which fills the rectangular space (in cross-section) 74.

[0063] One can further see from FIGS. 2B and FIG. 2C that the end face of the slightly reshaped centering section 16 comes to lie approximate at the center of the plastic component and in any event does not project beyond the lower side 78 of the plastic component. Thus a planar attachment surface 78 is present beneath the plastic component at the side of the plastic component 56 remote from the flange 14. Since the centering section 16 is formed here as a ring-like centering section a screw can straightforwardly be screwed into the thread 22 of the nut element coming from below in FIG. 2B and hereby a further component can be pressed against the planar attachment surface. At the same time the contact surface 40 of the functional element is pressed against the upper side 72 of the plastic component, so that a high quality attachment situation is achieved with the desired direct clamping. Since the adhesive is cured in the adhesive joint 74 a part of the axial loading of the screw connection is transferred via the adhesive in the adhesive joint 74 to the attachment surface 12.

[0064] The FIGS. 3A and 3B show an alternative embodiment of the functional element 10. The same reference numerals are used as in the embodiment of figs, 1A to 1C and 2A to 2C and it will be understood that the corresponding description also applies to the features which are designated with the same reference numerals.

[0065] The embodiment of Figs, 3Aand 3B has the difference that the attachment surface 12 extends over the full lower side of the flange 14 radially outside the centering section 16. The adhesive ring 30 also has a corresponding extent. In this way the two sided adhesive connection with a corresponding adhesive strength and a relatively simple form of the functional element 110 is achieved. A bolt element corresponding to FIG. 7 can be realised with a correspondingly extended attachment surface 12, i.e. also without a curved contact surface 40.

[0066] The FIGS. 4A to 4C show an embodiment which is very similar to the embodiment of FIGS. 2A-2C, which is why the same reference numerals are used in the corresponding drawings. It will be understood that the previous description also applies for components with the same reference numerals in FIGS. 4A-4C. This convention is also used in conjunction with the further Figures. The important differences between the embodiments in accordance with FIGS. 4A-4C in comparison to the FIGS. 2A-2C will now be described.

[0067] These differences are restricted to a raised portion 80 of ring shape around the central projection 62 of the die button 60. One can see from FIG. 4A that a plastic component now sits on the upper side of the ring-like step 80 and is thus somewhat above the ring surface 82 of the die button which surrounds the raised portion 80 of ring shape. The situation in the holder 50 is unchanged relative to the previous embodiment in accordance with FIGS. 2A-2C.

[0068] As a results of the closing of the press or of another device which is used in order to press the functional element 10 against the plastic component and the die button 60, the raised portion 80 of ring shape of the die button forms a ring recess 84 in the lower side 78 of the plastic component and at the same time, as can be best seen from FIG. 4C, a corresponding raised portion 86 on the surface of the plastic component, whereby the axial height of the adhesive with the adhesive joint 74 is reduced relative to the embodiment of FIGS. 2B and 2C. This can be of advantage, since frequently, the adhesive force of adhesives increases with the reducing thickness of the adhesive layer providing this layer still has an appropriate thickness. The axial height of the raised portion 80 relative to the surface 82 can with advantage be selected in the range between 0.2 and 0.5 mm. The difference between the axial height of the contact surface 40 and the attachment surface 12 is then so selected that the axial height of the adhesive layer in the region 74 amounts to approximately 0.1 mm if one takes account of the axial height of the raised portion 86 which approximately amounts to the axial height of the recess 84 or of the ring surface 80 relative to the surface 82.

[0069] In many plastic materials it is possible, to bring about such a permanent deformation by a ring step 80 of a die button 60.

[0070] In the event that this does not succeed or that it must be feared that the material of the plastic component would be hereby damaged in an impermissible manner, one can also provide-in the design of the plastic component-for a raised portion of ring shape at the plastic component, such as for example shown in FIGS. 5A and 5B. This embodiment also has the advantage that a reinforcement of the plastic component is present in the region around the hole 58, whereby a loading of the screw connection or loadings which occur in operation can be better fed into the plastic component 56.

[0071] Even if one does not operate with a raised portion of ring shape of this kind, one can in any event accurately determine the axial height of the adhesive joint and of the adhesive layer which forms here in that the axial height h (FIG. 1B) is correctly determined, i.e. the degree of the set-back of the attachment surface 12 relative to the contact surface 40 is correctly selected.

[0072] At this point it should be pointed out that the hollow design of the holder 50 in accordance with FIGS. 2A or 4A can be exploited so that a central longitudinal passage 90 is present there in order, by means of a longitudinally displaceable plunger in the passage 40, to press the finished component assembly away from the holder 50 after the component assembly has been finished.

[0073] FIG. 6 now shows how individual functional elements 10 can be inserted into corresponding openings 100 of a carrier band 102 so that the functional elements are arranged one after the other in a row. The carrier band 102 can be the carrier band 31 in accordance with FIGS. 1D and 1E, which is not however necessarily the case. If necessary, a plurality of rows of openings 100 can be provided in the carrier band so that plural rows of functional elements are also possible. By folding the carrier band back on itself, as is shown in 104, for example over a non-illustrated shaft, the functional elements 10 are buttoned out of the carrier band one after the other on movement of the carrier band 102 in the arrow direction B and they can then be moved into a feed passage of a setting head or to a position above a die button 60 by means of a movable finger or of a holder (both not shown) which directly receives the functional element, as schematically shown in FIG. 6. FIG. 6 shows however the situation after the attachment of the plastic component 56.

[0074] A large number of different types of adhesives are known for the connection of various components. The different types of adhesive can be classified on the one hand by their chemical bases and on the other hand by their solidification mechanism. For chemically hardening adhesives, often also termed reaction adhesives, the individual chemical components for the adhesive are introduced in the correct ratio into the adhesive joint. The solidification is achieved by chemical reaction of the components with one another. Basically, one distinguishes for reaction adhesives between two (or multi) component systems and single-component systems. In the present application, any kind of reaction adhesives can be used and for the sake of simplicity will be termed in the following as adhesives.

[0075] For two component adhesives two often spatially separated preparations are used. Monomers, the basic building stones of the polymer arising during the reaction, are present in these preparations.

[0076] One of the two preparations contains resin monomers (binder) whereas the other contains hardener. Further content materials can also be present in the preparations, such as for example stabilizers, thixotropic agents, accelerators, further additives, dyes or fillers. The two components must typically be mixed in the correct ratio with one another prior to the application. On contact of the binder and the hardener, the chemical reaction to form the adhesive polymer starts. This signifies that two component adhesives can only be processed within a certain processing time. Through the progressive reaction, the viscosity of the mixture continuously increases and can finally no longer join the two surfaces to be joined to one another after exceeding the processing time if these surfaces have not yet been brought together. After the connection of the surfaces by means of the adhesive, the curing time follows in which the end strength of the adhesive bond builds up. This curing time is affected greatly by external influences, in particular by the temperature. A temperature increase leads to an accelerated curing and often also to higher strength. In contrast to this, lower temperatures prolong the curing time. Three or multi-component adhesives are also manufactured which can be used as required.

[0077] Typical types of two (or multi) components and single-component systems are cyanacrylate adhesives, methylmethacrylat adhesives, anaerobically curing adhesives, radiation curing adhesives, phenol formaldehyde resin adhesives, epoxy resin adhesives and polyurethane adhesives.

[0078] With the special requirements which are placed on a functional element it is important to provide an adhesive composition in non-cured form at the functional element and indeed in such a way that the functional element with the non-cured adhesive can be stored over a longer period of time for days, through months up to years, without the adhesive curing. Known are also adhesive systems in which the individual components are present in micro-capsules or nano-capsules. The following types of systems are possible: [0079] a) One component of the adhesive, the first component, is introduced in micro-capsules or nano-capsules into the second component, with the second component being designed so that it bonds the micro-capsules and nano-capsules to one another and bonds these to the functional element. The first component does not however harden (or cure) without contact with the second component, but rather the second component functions as a weak adhesive, similar to the adhesive in adhesive notices (Post It). Only when the micro or nano-capsule burst, is the first component released into the second component so that the two components enter into contact and cure and a high adhesive force is developed. [0080] b) Both components of the two components adhesive are respectively accommodated in micro- or nano-capsules and these are then mixed with a third component, with the third component having the task of keeping the first and second encapsulated components together and of bond them onto the functional element. Only a small quantity of the third component is used, just so much as is necessary to achieve the above-designated functions but not so much that the presence of the third component prevents a high quality adhesive bond arising by reactions between the first and the second compounds. [0081] c) Multi-component adhesives can also be used which are each respectively accommodated in micro-capsules or nano-capsules and then react with one another when the capsules (as in the above examples) are caused to burst by the action of pressure. A binder must also be provided with such multi-component adhesives which holds the individual capsules together in mixed form and binds them to the respective functional element.

[0082] An example for a three component adhesive would be an epoxy resin as a first component, an epoxy resin polymeric compound as the second component and a hardener, for example in the form of a peroxide as the third component.