FR2723409A1 - Plastics holder for countersinking and fusing in plastics component - Google Patents

Abstract

Plastics holder (1) has: (a) a holding part (1), and (b) a porous strip (2), esp. a fleece or porous membrane which is firmly bonded to its surface by taking up melt of the holding part. Also claimed are methods for producing a bondable plastics holder and countersinking this in a plastics component.

Description

 The invention relates to a plastic retention element which is intended to be integrated into a plastic construction element, in particular of thermoplastic material, the connection between the integrated retention element and the plastic construction element being obtained by fusion and resolidification of at least one of the elements to be connected, preferably due to a mixture of solidified solidified materials of the two elements. The invention further relates to a method for manufacturing and gluing a plastic retainer.

 For the insertion of plastic retaining elements in panels, such as lightweight construction panels of the sandwich type or layers of insulation, or panels with foam or cellular structure, a method can be used. with the help of which integration and fusion, namely welding, of the retaining element and of the panel are carried out.

For this purpose, a retaining element, which is substantially designed as a body of revolution in a thermoplastic material, is pressed on the construction element and rotated relative to the construction element at a speed such that a welded connection is obtained by the heat generated at the contact surfaces of the two elements. Such a fixing method is for example known from DE-OS 41 41 616. These retaining elements inserted in a panel can be used to fix an object between the head of a retaining element and the building element, or forming a fixing point for anchoring a screw in the plastic building element. It is often desirable to glue another layer, for example a backing, on such panels provided with retaining elements and / or on the retaining elements, or to fix the panels themselves by means of gluing. .

In case of repair of a building element or a plastic panel, or the subsequent insertion of a retaining element, it is also desirable to glue their surfaces. Even if plywood or the like is applied to the entire surface of a plastic building element, the most suitable places to stick another object to the plywood are those under which a retaining element is placed can be glued. This is due to the fact that the plywood regularly adheres significantly better to the retaining element, and can therefore be more stressed at this location. However, not all plastics are suitable for a bonded bond, or the bonding power is often insufficient. As soon as a thin coating of the counter-plating type is for example applied to a panel provided with a retaining element, blisters, marks, blisters, etc. may appear if the retainer is not sticky.

 The object of the invention is to provide a plastic retention element intended to be inserted into a plastic construction element, the surface of which is suitable for a bonded connection, as well as a composite material consisting of a retainer and a plastic building element. In addition, a plastic retaining element must be presented, the underside of which is particularly suitable for being inserted by fusion into a plastic construction element, in particular if abrasion in the form of particles is formed by friction. the rotation. There must also be proposed methods which are intended for the manufacture and sizing of a retaining element made of plastic material, which at the origin was not or hardly suitable for sizing. In addition, a process must be made available which allows a particularly trouble-free insertion of a plastic retaining element into a plastic construction element.

 This objective is achieved by a plastic retaining element intended to be integrated and inserted by fusion into a building element, preferably of thermoplastic material, characterized by a retaining element, and a porous strip firmly connected to the upper face of the latter by absorbing molten material from the retaining element, in particular a nonwoven or a porous membrane.

 According to another aspect of the invention, this element is characterized in that, at least on its underside, it comprises a substantially horizontal slot, which extends substantially in the direction transverse to the direction of rotation, which is intended to collect the abrasion generated during insertion by rotation into a plastic building element.

 The invention also covers a composite material comprising (a) a plastic construction element and (b) one or more retaining elements as mentioned above.

The invention also provides a process for the manufacture of a sizing retainer made of plastic material, comprising the following phases
- application of a porous strip on the surface
a retaining element, in particular a nonwoven
or a porous membrane,
- heating the surface of the retaining element
to generate a plastic fusion,
especially by means of treatment
thermal or ultrasonic,
- connection of part of the porous strip with
melted material in order to establish a bond
solid between the surface of the retainer
and the porous strip by forming a zone
can be bonded to the surface of the retaining element
made of plastic, which consists of
minus part of the porous strip.

 According to another aspect of the invention, the method is characterized in that a retaining element as mentioned above, or manufactured in the aforementioned manner, is connected to the plastic construction element by the establishment of a welded connection generated by friction heat between the plastic retention element and the plastic construction element.

 According to yet another aspect of the invention, the method characterized by the establishment of a bonded bond between a material to be bonded and the porous strip of a plastic retaining element as mentioned above or manufactured in the aforementioned manner.

 Thanks to the invention, it is obtained that plastic retaining elements according to the invention, intended to be integrated into a construction element of thermoplastic material, are particularly suitable for establishing a bonded connection, the fixing of the element retained in the construction element being obtained by the fact that the fusion insertion of the retaining element in the construction element is carried out by friction heat. A fusion of the surfaces of the elements is obtained by a corresponding choice of plastics, which results in resistant welding between the retaining element and the construction element. It is also obtained that plastic retaining elements intended to be integrated into a construction element of thermoplastic material have particularly advantageous properties for insertion by fusion into the plastic construction element, even in the event of formation of 'abrasion.

 According to one aspect of the invention, a plastic retaining element has on its upper face a porous strip which, by absorbing molten material from the retaining element, is firmly connected to the latter. The melting point of the porous strip is preferably higher than that of the material of the retaining element. The porous strip also has locations which have not absorbed molten material. These locations can easily be glued. The locations of the porous strip having absorbed molten material provide a strong connection with the retaining element. It is possible to subject certain parts of the surface of the strip and of the surface of the retainer from the start to heat or ultrasonic treatment so that the molten material of the retainer cannot essential penetrate completely vertically only in the treated locations, and / or avoid complete vertical penetration of the strip by placing a layer which is not permeable to molten material or by choosing a sufficiently thick strip . If the melting point of the strip or its underside facing the retainer is the same as that of the surface of the retainer, the molten material is absorbed by the strip in the form of a certain mixture molten material from the retainer and the strip.

 Particularly favorable results are obtained with a retaining element which, after treatment with a heating plate comprising a plurality of recesses, has numerous elevations. At the level of the surfaces of the raised areas themselves, no material penetrates into the porous strip, so that these locations are particularly suitable for sizing.

 In the center of the retaining element which is not yet provided with the porous strip, there may be provided a centering hole or centering hole to facilitate the introduction of a tool, and one or more slots intended for the introduction of a tool, for example parallel slots, passing through the center of the surface of the retainer. This means makes it possible, even after the resistant fixing of the porous strip, to very easily introduce a tool intended to generate a rotational movement Chamfers provided additionally, preferably at the level of the upper edges of the slots and of the centering bore, prevent that this surface structure be closed or filled during the installation of the nonwoven and facilitate the coupling of the drive tool, whether or not with nonwoven. This also applies when the slot is made with a width which is approximately twice that of the blade of the drive tool, which is however at least mm wider. By providing one or more through slots on the surface in conjunction with the centering hole, reliable access is created for a drive tool, for example a drill with adapter.

By this means, it is possible to generate a sufficiently high rotational speed of the retaining element in order to allow the penetration of the retaining element into the building element, as described in DE-OS 41 41 616, and obtain a friction fusion to establish a connection between the elements. A particular advantage lies in the fact that the slots and the centering hole simultaneously cause better penetration of the adhesive from the porous strip fixed on the retaining element, and a discharge or absorption of the excess adhesive. When mounting the retaining element, the porous strip may be partially degraded, deteriorated or torn off. The absorption of the glue (liquid / paste) is not necessarily altered by this fact, it is even obtained better penetration and bonding.

 A typical material for the retainer is polypropylene, which is generally not very sticky.

For the porous strip to be applied and then to be bonded to the plastic retaining element, a nonwoven with a polyester or felt texture is notably taken into account. The plastic construction element, into which the retaining element according to the invention is inserted, is frequently made of identical material.

 For reasons of production technique, it is advantageous that the upper and lower faces of the plastic body of the retaining element are arranged in the same way. When fusing the plastic retainer into the plastic construction member, raised or depressed areas on the underside of the retainer are generally advantageous. These elevations or recesses can for example also be executed in the form of an inscription or a logo of a firm. A star-shaped surface structure makes it possible, for example, to eliminate the abrasion generated during the friction insertion of the retaining element.

 For an optically pleasing arrangement of a composite material consisting of a plastic building element and a retaining element, the surfaces of the latter can be aligned with one another or flush. Such a structure is more particularly suitable for the application of another layer on the composite material, for example a backing.

 Thanks to the specific arrangement, according to another aspect of the invention, of the underside of a plastic retaining element which is intended for integration and insertion by fusion into a construction element made of plastic, or by welding the two elements, a particularly easy insertion and a reliable fusion effect can be obtained. The fact that substantially horizontal slots, which extend substantially in the direction transverse to the direction of rotation, are provided on the underside of the retaining element, favorably and effectively influences the insertion properties of the retaining element in the building element. Radial recesses of this type on the underside of the retaining element, as is for example the case for a star shape, but also for an appropriate spiral shape, allows the absorption of particles of abrasion produced Far friction between the retainer and the building element. This means enables the reliable insertion of the retaining element by friction fusion, even in the case of materials as critical as light PVC or polystyrene foams. Slots with a width of the order of 1 to 2 mm and a depth of the order of 2 mm, for example, are well suited for a retaining element with a diameter of 30 mm and a height of 15 mm.

 The underside of the retaining element advantageously consists of a ring, and in particular prefer several concentric rings, which have recesses or slots. The slots made on several rings preferably form one or more slots interrupted by the spaces existing between the walls of the rings, extending over the entire underside of the retaining element.

 During the insertion by rotation of the retaining element, these rings ensure a certain stability and thus prevent an offset of the retaining element, which allows a safe and targeted installation in the construction element. The fact that the underside of the retaining element is not made of solid material facilitates insertion into the building element. The particularly important point is however the additional resistance of the connection which can be obtained with the rings between the retaining element and the building element. It has indeed been found that a particularly good fusion connection, between the retaining element and the construction element, is established precisely at the edges or ribs of the underside of the construction element. , which are frequently rounded. The resistance of the bond between the elements is essentially determined by this area. By providing additional edges at the underside of the retaining element by means of annular walls, which act in the building element, the quality of the bonding resistance between the retaining element and the construction is influenced very favorably. Indeed, thanks to the ring or rings it is obtained a heat concentration which allows a targeted fusion.

By providing recesses or grooves in the rings, a retaining element thus designed can also be anchored in a particularly reliable manner in plastic construction elements made of critical material, namely a material which is brittle and which fragments during the insertion by rotation of the retaining element and thus releases powder or particles, such as for example light foams of
PVC or polystyrene. Indeed, the particles generated by friction, which hinder the formation of fusion, are evacuated from the marginal zones of the rings during insertion by rotation of the retaining element by the recesses made in the rings of the lower face of the retainer. The particles are thus collected, either in the recesses themselves, or in the intermediate spaces between the rings.

 The upper face of the retaining element may in particular be designed in the same way as that of the retaining element described in the introduction, in particular be provided with drive slots and be of identical design to the lower face of the retainer. In addition, and as described above, a porous strip can be applied to the surface of the retaining element to make it sticky.

Other advantages, features and possibilities of application of the present invention arise from the following description of embodiments in relation to the drawings, in which
Figure 1 shows a retainer
having a porous strip connected
by points in several places of
the surface,
Figure 2 is a sectional representation of a
retainer which, following the
fixing the porous strip
performed by heating, formed a
surface structure with
elevations,
Figure 3 is a top view of an element
restraint according to FIG. 2,
Figure 4 shows a retainer
with ribs or
grooves extending parallel to
the surface of the retainer,
FIG. 5 represents a retaining element of which
the surface has a drilling of
centering and a slot, Figure 5a
being a vertical section of
the retainer,
FIG. 6 represents a composite material with
honeycomb structure consisting of
retainer and an element of
plastic construction
according to the invention, the element of
restraint being glued, and
Figure 7 is a bottom view of an element
plastic retainer which
has a bottom side
specially adapted for insertion
by fusion in an element of
plastic construction.

 FIG. 1 represents a retaining element 1 of plastic material on which is being fixed a porous strip 2 by means of a heating device 3. The heating device 3 comprises points or ribs which heat the surface the retaining element 1 through the porous strip 2 and generate a fusion. This fusion penetrates into the porous strip at the locations concerned and ensures at these locations a solid fixation between the porous strip 2 and the retaining element 1. Unlike the remaining areas of the porous strip, the areas of the porous strip into which penetrates melted plastic is less suitable for sizing. Since sufficiently large zones are however provided in the strip 2, into which the molten material 8 does not penetrate, the retaining element 1 shown is remarkably suitable for subsequent gluing. For the installation of the porous strip 2 it is in principle possible, either to first heat the surface of the retaining element and then to apply the strip 2, or to heat the surface of the retaining element already provided with band 2.

 For subsequent gluing, it is particularly advantageous to have a surface structure which, as shown in FIG. 2, can receive glue deposited on raised surfaces 4 which is distributed by pressure during the application of a layer to stick. FIG. 2 shows several elevations which are generated simultaneously with the fixing of the porous strip as an intermediate layer to be bonded. The heating device 3 shown is produced in the form of a heating plate comprising several orifices. During the previous application of the heating plate 3 on the retaining element 1 provided with the porous strip 2, of the molten plastic stems.

formed on the surface of the retainer. Molten material has in this case penetrated into the orifices of the heating plate 3 and thus formed raised areas 4. These raised areas 4 protrude from the surface of the retaining element by an order of magnitude of about 1 mm. No molten material enters the porous strip at the surfaces of the raised areas 4 themselves, because the locations in the zone of the orifices of the heating plate 3 are not heated.

On the other hand, the molten material 8 penetrates in a particularly intense way into the porous strip 2 at the periphery of the raised areas, in particular at the level of the upper edges of the latter. In the hollows and in the areas surrounding the elevations, the porous strip is thus firmly connected to the surface of the retaining element. At the surfaces of the raised areas 4 which are not impregnated with the molten material, the retaining element thus obtained is remarkably suitable for sizing. The surface structure of the resulting retaining element is shown in FIG. 3. This figure shows that a plurality of surface elevations constitutes a suitable base for making a bonded bond with an object to be attached or fixed to it. .

 Figure 4 shows a retaining element 1 which has three parallel ribs 4. The porous strip 2 was applied to its surface. Then the ribs 4 protruding from its surface were heated by means of the heating plate 3. Molten material 8 can therefore be generated and penetrate into the porous strip 2 only at the level of these ribs 4. During this process and in to the extent that this is desired, a certain leveling of the surface can be simultaneously obtained by the fusion of these ribs 4. Since the hollows in the surface of the retaining element are not heated by means of the smooth heating plate , the porous strip 2 remains substantially free of molten material at this location and is suitable for sizing.

The insertion by rotation of the retaining element 1 of plastic material into a construction element 6 of thermoplastic material is facilitated since, as shown in FIG. 5, means are provided on the surface of the retaining element 1 for the introduction of a corresponding tool. The retaining element according to FIG. 5 has a central centering hole 9 and a surface slot or groove 5 passing through the center of the retaining element 1. Thanks to these arrangements, it is possible to create a particularly safe introduction and reliable for a tool which is produced in the form of a blade comprising in the middle a projecting part. A tool of this type can for example be used in a drill. The retaining element 1 can be inserted and fixed in the plastic construction element 6 both before and after the fixing of the porous strip 2. In the latter case in particular, it is advisable to provide the slot 5 and the centering hole 9 of a chamfer, as shown in Figure 5a, or to provide in an upper part a larger diameter of the centering hole 9 (not shown). This means facilitates the installation of the tool.

 FIG. 6 illustrates an example of use of the retaining element 1 which can be glued. This representation shows a composite material which consists of a retaining element 1 to which a nonwoven of polyester texture is applied, and of a construction element 6 of plastic material having a honeycomb structure. Not only the plastic of the retaining element, but also the material of the building element 6, are made of polypropylene. In this case, the nonwoven has been chosen with a thickness such that, when it is fixed to the surface of the retaining element, the molten material penetrates it only approximately up to half. The retaining element is inserted and fixed in the plastic construction element 6 by means of friction welding. Thanks to the insertion by rotation of the retaining element 1 into the construction element 6 by means of a start of fusion of the respective friction surfaces, a welded connection has been established between the two elements at the level of the zones 14. An adhesive 13 is applied to the nonwoven 2, which glues the material 7 deposited on the retaining element 1. The construction element thus prepared is then used for cooling cells, bodies of motor cars, in the naval and aeronautical construction, the retaining elements being for example used for the fixing of door elements or for the connection of different panels.

 Figure 7 is a bottom view of a plastic retaining element 1, which has been specially adapted for insertion and fusion in a plastic construction element 6. The retaining element 1 comprising the three concentric rings 10 penetrates much more easily into a plastic building element than a retaining element whose underside is made of a solid and flat material. The rings 10 exert a certain centering effect during the insertion by rotation of the retaining element 1, so that the retaining element can more difficult be offset from the desired insertion point. The rings 10 above all ensure a particularly judicious formation of molten material at the level of the rings, which at the bottom come into contact with the material of the building element through their edges. The fixing in the building element is therefore particularly resistant.

Depending on the materials of the retaining element 1 and the construction element, a mixture of molten materials of the two elements is established regularly at these locations, so that a welded connection is obtained during cooling. There are also recesses 11 in the rings 10. By this means, powder or particles generated during the insertion of the retaining element 1 into a construction element can be evacuated from the marginal zones, and the potential molten material is significantly improved at the level of the retaining element 1 or the building element. This means makes it possible in particular to also achieve a good welded connection of the two elements in a PVC foam, in the case of which abrasion particles are generated to a significant degree during the insertion by rotation of the retaining element 1 The two faces of the retaining element can be designed in an identical manner and this mainly since, as described in this example, the recesses 11 form a slit on the surface. Such a slot on the surface of the retaining element 1 can in fact be used for the installation of a drive tool. Besides, and as described above, it is also possible to apply a porous strip to this surface structure.

Claims (48)

 1. Retaining element (1) made of plastic intended to be integrated and inserted by fusion into a building element (6), preferably made of thermoplastic material,  characterized by  a retaining element (1), and  a porous strip (2) firmly connected to the upper face of the latter by the absorption of molten material from the retaining element (1), in particular a nonwoven or a porous membrane.  2. plastic retaining element according to claim 1, characterized in that the junction between the integrated retaining element (1) and the construction element (6) consists of a mixture of molten material solidified from the two elements.  3. plastic retaining element according to claim 1, characterized in that the porous strip (2) is only firmly connected to the retaining element (1) by a part of its surface.  4. Plastic retaining element according to any one of the preceding claims, characterized in that the porous strip (2) is substantially firmly connected in points to several surface areas of the retaining element (1).  5. plastic retaining element according to any one of the preceding claims, characterized in that the porous strip (2) is securely connected to the raised surfaces (4) of the retaining element, the remaining surface of the retaining element being substantially free of a solid connection with the porous strip (2).  6. plastic retaining element according to claim 5, characterized in that the elevations (4) are arranged as ribs extending parallel to the surface of the retaining element.  7. plastic retaining element according to any one of the preceding claims, characterized in that, on elevations (4) formed on the retaining element (1) during the fixing of the strip (2), the porous strip (2) is substantially free of a solid connection with the retaining element (1), the porous strip (2) enveloping the elevations (4) laterally and applying by a solid connection against the retaining element (1) in the recesses of the surface of the retainer.  8. Plastic retention element according to any one of the preceding claims, characterized by a hole or centering hole (9) intended for the introduction of a tool to generate a rotational movement.  9. plastic retaining element according to any one of the preceding claims, characterized by a slot (5) passing through the center of the surface of the retaining element, intended for the introduction of a tool for generating a rotational movement.  10. Plastic retaining element according to any one of the preceding claims, characterized by eccentric holes intended for the introduction of a tool to generate a rotational movement.  11. plastic retainer according to any one of the preceding claims, characterized in that recesses in the surface of the retainer are designed as parallel or star-shaped grooves.  12. plastic retaining element according to claim 10, characterized in that the parallel grooves are designed as slots (5) intended for the introduction of a tool to generate a rotational movement.  13. plastic retaining element according to any one of claims 8 to 11, characterized in that the slot (s) (5) and / or the centering bore (9) comprise a chamfer.  14. plastic retaining element according to any one of claims 8 to 12, characterized in that the centering bore (9) and / or the slot (5) are covered by the porous strip (2).  15. plastic retaining element according to any one of the preceding claims, characterized in that the retaining element (1) essentially consists of a polyolefin, in particular polyethylene, polypropylene, preferably of polypropylene or polystyrene or polyvinyl chloride.  16. plastic retaining element according to any one of the preceding claims, characterized in that, at least on the upper face opposite the retaining element (1), the porous strip (2) has a melting point higher than the material of the surface of the retainer (1).  17. plastic retaining element according to any one of the preceding claims, characterized in that the porous strip (2) has the same melting point as the material of the retaining element (1)  18. plastic retaining element according to any one of the preceding claims, characterized in that the porous strip (2) consists of a nonwoven.  19. plastic retaining element according to any one of the preceding claims, characterized in that the nonwoven consists of a texture, a fabric, a felt or a nonwoven material, in particular d '' a polyester texture.  20. Retaining element according to any one of the preceding claims, characterized in that the porous strip (2) consists of fibers of polyester, glass, polyamide, polypropylene, polyphenylene sulfide, preferably polyester.  21. Plastic retaining element according to any one of the preceding claims, characterized in that the retaining element (1) has the shape of a cylinder with a circular base.  22. Plastic retention element according to any one of the preceding claims, characterized in that the underside of the retention element has a substantially horizontal slot, which extends substantially in the direction transverse to the direction of rotation.  23. Selor plastic retainer. any one of the preceding claims, characterized in that the underside of the retaining element comprises concentric rings (10).  24. Plastic retaining element according to any one of the preceding claims, characterized in that the concentric rings (10) have recesses (5).  25. plastic retaining element according to any one of the preceding claims, characterized in that the recesses (5) in the concentric rings (10) are designed for the introduction of a tool intended to generate a rotational movement .  26. plastic retaining element according to any one of the preceding claims, characterized in that the lower face of the retaining element is designed in the same way as the upper face of the covered retaining element (1) by the porous strip (2).  27. Plastic retaining element according to any one of the preceding claims, characterized in that the slot (s) (5) extend vertically through the assembly of the retaining element (1).  28. Plastic retention element intended to be integrated and inserted by fusion into a plastic construction element, characterized in that, at least on its underside, a retention element (1) has a slot (5) substantially horizontal, which extends substantially in the direction transverse to the direction of rotation, which is intended to collect the abrasion generated during insertion by rotation in a building element (6) made of plastic.  29. Plastic retaining element according to the preceding claim, characterized in that at least one slot (5) or a groove passes through the center of the lower face of the retaining element.  30. Plastic retaining element according to the preceding claim, characterized in that slots (5) or grooves extend in the shape of a star on the underside of the retaining element.  31. Plastic retaining element according to any one of the preceding claims, characterized in that several parallel slots (5) are formed on the underside of the retaining element.  32. Plastic retaining element according to any one of the preceding claims, characterized in that a retaining element (1) has concentric rings (10) at least on its underside, the outer ring at least comprising preferably one or more recesses (5) in the form of a slot.  33. Plastic retaining element according to the preceding claim, characterized in that each of the concentric rings has recesses (5) in the form of a slot, the recesses (5) being oriented so that at least one results continuous slit (5) which is interrupted by the empty spaces existing between the rings.  34. Plastic retaining element according to the preceding claim, characterized in that the two surfaces are of identical design.  35. Composite material comprising  a) a building element (6) in material  plastic,  b) one or more retaining elements according to  any of the claims relating to  the retainer.  36. Composite material according to claim 35, characterized in that there is a fusion connection between the retaining element (1) and the construction element (6) made of plastic.  37. Composite material according to one of the preceding claims concerning the composite material, characterized in that the exterior surfaces of the retaining element (1) and of the construction element (6) are flush.  38. Composite material according to one of the preceding claims relating to the composite material, characterized in that the porous strip (2) is disposed on the construction element (6) made of plastic.  39. Composite material according to one of the preceding claims concerning the composite material, characterized in that, at least in the core, the construction element (6) made of plastic material has a foam or cellular structure.  40. Composite material according to claim 34, characterized in that the cells of the honeycomb structure of the construction element (6) are substantially oriented perpendicular to its surface.  41. Composite material according to one of the preceding claims relating to a composite material, characterized in that the building element (6) made of plastic material is essentially made of one of the materials that are polyvinyl chloride, 1 'Sd3S, ie polypropylene, polyethylene, polycarbonate, polystyrene, partially crosslinked polyurethane.  42. Process intended for the manufacture of a sizing retainer made of plastic material, comprising the following phases  - application of a porous strip (2) on the  surface of a retaining element (1), in particular  a nonwoven or a porous membrane,  - heating the surface of the retaining element  to generate a plastic fusion,  especially by means of a treatment  thermal or ultrasonic,  - connection of part of the porous strip (2)  with the melt in order to establish a  solid bond between the surface of the element of  retaining and the porous strip (2) forming a  bonding area on the surface of the element  plastic retainer, which consists  at least part of the porous strip (2).  43. Method according to the preceding claim, characterized in that the surface subjected to a start of melting of the retaining element (1) provided with the porous strip (2) is pressed against a sheet generating a surface structure, comprising in particular recesses or holes or orifices, preferably a heating plate, and in doing so connects the strip, at least in a partial area, to the -surface structured as a consequence of the retaining element (1).  44. Method for manufacturing a plastic building element (6) to which the retaining element is fixed, characterized in that an element is connected to the plastic building element (6) retaining device (1) according to any one of the claims relating to plastic retaining elements, or a plastic retaining element manufactured according to any one of the claims relating to the method of manufacturing sizing retaining elements, by the establishment of a welded connection generated by friction heat between the retaining element (1) of plastic material and the construction element (6) of plastic material.  45. Method for gluing a plastic retaining element, characterized by establishing a bonded connection between a material (7) to be glued and the porous strip (2) of a plastic retaining element according to one any one of the claims for plastic retainers or a plastic retainer made according to any one of the claims for the method of making glued retainers.  46. Method for integrating a plastic retaining element (1) according to any one of claims 28 to 34 in a plastic construction element (6) which has, at least in the core, a foam or cellular structure, characterized in that the retaining element (1) is pressed on the construction element (6) and rotated relative to the construction element (6) at a speed such that the retaining element (1) penetrates into the construction element (6) by forming molten material at the level of the concentric rings (10), the particles generated by the friction being evacuated by means of recess (s) ) (5).  47. Method according to the preceding claim, characterized in that the construction element (6) made of plastic material consists, at least in the core, of thermoplastic material, and that at the transition points between the retaining element ( 1) and the construction element (6) the molten materials (8) of the two elements mix and weld the two elements together after the retaining element (1) has stopped.  48. Method according to claim 44 or 45, characterized in that the building element (6) made of plastic material consists of one of the materials that are polyvinyl chloride, ABS, polystyrene, polypropylene, polyethylene, partially crosslinked polyurethane.