MXPA96004148A - Process for molding a hollow profile heap on an article of type of lam - Google Patents

Abstract

When a frame-type hollow profile strand is extruded onto a glass sheet (1), the transitional region of the start and end of the extruded strand is reshaped with the aid of an injection mold (13). At the location to be reshaped, first the entire irregularly molded portion is mechanically removed. Then, a wax core is pushed into the hollow space of the two mutually adjacent end portions of the hollow profile strand. The injection mold (13) is then put in place, and the hollow profile strand is completed at this location by injection of a healing elastomer. Subsequently, the portion of the profile strand thuscompleted is heated to such a degree that the core melts and the wax is distributed as a layer (22) on the bottom of the hollow space (

Description

PROCESS FOR MOLDING A HOLLOW PROFILE OF A SHEET ON AN ARTICLE OF TYPE OF SHEET DESCRIPTION OF THE INVENTION The invention relates to a process for molding a hollow profile strand of an extrudable elastomer over the peripheral region of a sheet-like article. It is known to provide sheet-like articles on the periphery with a hollow profile strand of a permanently flexible polymer, since the hollow profile strand is extruded directly onto the article from an extrudable elastomer that adheres to the article. For example, EP 0188391 Bl describes an adhesive bond for the adhesion of a glass sheet to a window frame, wherein the adhesive strand consists of a permanently flexible polymer and has a continuous hollow space. In this case, the hollow space aims to facilitate the removal of the glass sheet, if this is necessary. For this purpose, the hollow space is filled with a free, pressurized fluid medium, by means of which the polymer strand is deformed and the glass sheet is forced out of the frame. The polymer strand can then be cut into a simple shape with a cutting tool.

In this way, it is possible, with the aid of the extrusion process described in EP 0188391 Bl to extrude on a sheet type object, for example on a glass sheet or on a component consisting of any other material, such as on a window frame, or on the leaf of a door, on a cover or the like, a hollow profile thread of an elastomer, which aims to perform a sealing function. This is because the tubular profiles of an elastomer are particularly suitable for sealing functions. If a enclosed frame is to be extruded onto a sheet type article, it is necessary to reshape the transitional region between the beginning and the end of the extruded polymer strand. A known process of this, from EP 0524060 Al provides for a locally limited portion of the polymer strand to be mechanically removed in the region of the transition after curing the polymer strand and, with the aid of a similar process of injection molding, for this region of the article is going to be surrounded by a two-part mold and the polymer strand will be completed by injection into the mold of a relatively fast healing polymer, which enters a permanent bond with the two end regions of the polymer profile and with the surface of the sheet type article.

If the extruded profile strand is a hollow profile strand, which also aims to retain the flexibility of the tubular profile at the transitional location between the beginning and the end of the extruded polymer strand, the known process can not be used to return to mold the transitional region. This is due, to produce a hollow profile, the injection mold has to be provided with a core. However, after carrying out the operation of remodeling, a core can not be removed, then the tube is completely closed. The invention is based on the object of providing a process for molding a hollow profile strand of an elastomer, which is also capable of extruding an enclosed frame, comprising a hollow profile, on an article and of performing a necessary hollow profile strand in certain locations, so that the elastic deformability of the hollow profile is also retained in the re-cast location. The process according to the invention for achieving this object is distinguished in that a locally limited portion of the cured profile strand is mechanically removed, at least partially, at a location of a hollow profile strand to be reshaped, a core connecting the end portions between them is pushed into the space of the two mutually adjacent outer portions of the hollow profile strand, the part of the article that has the region to be molded is surrounded by an injection mold and the hollow profile strand is completely in this location by injecting a healing elastomer into the injection mold, and subsequently the core is destroyed in such a way that the core material is distributed in the hollow space of the profile strand. The destruction of the core, in this case, is going to be carried out so that the inner wall of the hollow space in the region of the inserted core is exposed to at least a certain degree that the tubular profile is given an adequate elasticity, also in this Location. In principle, the process according to the invention can be carried out in several ways. For example, it is possible to use a core comprising a small thin-walled tube of a brittle material and to destroy this core in a mechanical form, for example by applying pressure to the profile portion that is reshaped. The fragments of the small tube thus produced remain in the hollow space of the tubular profile, without influencing the serviceability of the sealing profile in a harmful manner. Such cores may consist, for example, of a brittle ceramic or of a brittle and brittle polymer or of a ceramic or plastic foam type material.

According to another embodiment of the process according to the invention, a core of a low melting material is used, which is destroyed by subsequent heating after the end of the hollow profile strand. The heating of the core, following the current reshaping operation, is in this case taking dependence on the material used in the particular case for the core, so that the core is completely melted and the molten core material is distributed over a section as long as possible in the lower part of the hollow space, so that at least the upper part of the tubular sealing profile is given the required elasticity so that it is capable of performing the sealing function in this location, too. To extrude a hollow profile strand onto a sheet type article, both reaction systems and thermoplastic elastomer systems can be used. Since the embodiment according to the invention with the mechanical destruction of the core is suitable for both systems, in this form, the embodiment according to the invention with thermal destruction of the core is preferably suitable for hollow profiles from a system of reaction, since in the case of a thermoplastic elastomer system there is a risk that when heated to destroy the core, the elastomer profile itself will also be affected. Although in this case, the destruction of the core by thermal means is possible in principle, the degree and duration of the heating must then be matched precisely to the materials used in the particular case. The process according to the invention with the thermal destruction of the core can be used with particular advantage in cases where the reaction systems, in which the polymerization reaction is accelerated by supplying heat, are used so that the transitional regions are recast, with the result that the thermal energy initially supplied causes the molded part to become dimensionally stable and subsequently cause the core to melt. The heat supply required to melt the core material takes place by means of the hot injection mold. However, if the heating of the reshaped profile portion effected by the injection mold is not suitable for melting the core, the heating necessary for melting is carried out by a subsequent heat exposure when the injection mold has been removed again from the profile thread. Suitable, in particular as the material for cores of fusion materials are hard paraffins and waxes with a high melting point. Both hard waxes and waxes with a high melting point are available with different melting temperatures, with the result that the materials suitable for the individual case can be selected from this group of materials without any problem. The hard paraffins are corriereially available, for example with melting temperatures of about 50 to 130 ° C and the waxes are commercially available with melting temperatures of about 50 to 200 ° C. If appropriate, the appropriate material in the individual case will be determined by analysis. But not without saying that other materials can also be used, with a low melting point, for example metal alloys with low melting point or suitable thermoplastics. An exemplary embodiment of the invention is described in more detail in the following with reference to the drawings, in which: Figure 1 shows a sealing frame, comprising a hollow chamber profile, extruded on the peripheral region of a glass sheet, in the transitional region of the beginning and end of the extruded profile strand; Figure 2 shows the transitional region shown in Figure 1 after the mechanical removal of the hollow profile portion and the insertion of a nucleus; Figure 3 shows a section through the mold by injection to reshape during the operation for reshaping, and Figure 4 shows a section through the injection mold for reshaping after core fusion. In the sample drawings, the peripheral section of a glass sheet 1, which is provided with a tubular hollow chamber profile 2 running around one of its surfaces along its periphery. The glass sheet 1 is shown as a monolithic glass sheet, but it is obvious that it can also be a multilayer laminated glass sheet. Usually, such glass sheets, as used for example as automotive glass sheets, are provided in the peripheral region with an opaque layer 3 of a baked finish frame, which has the task of protecting the profile frame against UV rays. The hollow chamber profile 2 is extruded with the aid of an extrusion process directly on the glass sheet 1 or on the opaque layer 3. If appropriate, the extrusion process is preceded by a pretreatment of the glass or glass surface. the surface of layer 3 and / or coating with a suitable adhesion promoter. The corresponding extrusion processes are known and apart from EP 0188391 Bl, already mentioned at the beginning, they are described, for example, in EP 0121481 Bl and in EP 0524092 Bl. For this purpose, the extrusion die is placed on the glass sheet at location A, taken along the periphery of the glass sheet and, after going around the glass sheet and reaching location A, the glass sheet is raised and at the same time the volume flow of the polymer in the extruded state is interrupted. At location A, where the beginning and the end of the extruded hollow chamber profile strand coincide, an irregularly molded accumulation 4 of the polymer is inevitably formed, and it is inevitable that the continuous hollow space 5 of the profile strand be closed . Once the profile frame of the hollow chamber 2 has been produced in this way by extruding on the glass sheet 1, the profile of extruded polymer 2 is allowed to cure to such a degree that it can be divided cleanly, without presenting plastic deformations, thus occurring in the cut locations. Then, the profile thread 2 is cut with a suitable cutting tool along the planes S, in each case in a location in which the profile thread 2 has a satisfactory cross section. Similarly, the lower part of the profile thread 2 is cut in a plane running parallel to the surface of the glass just above the surface of the glass, so that the lowermost layer 6 remains as a layer of thin polymer with a high adhesion on the surface of the glass or on the opaque layer. Instead of using suitable cutting tools, the removal of the cured polymer composition in this transitional region can also take place with the aid of a planing or grinding tool suitable for this purpose. If appropriate, the lower part 6 can also be completely removed. However, since under these circumstances it is difficult to remove the fully cured polymer composition from the layer 3 without damaging the layer 3, which can then possibly be seen through the glass sheet 1, it is advantageous to leave the layer lower 6 of the extruded profile strand on the glass sheet. When the profile thread 2 on the glass sheet 1 has been prepared in the manner described, if appropriate, the dividing surfaces are treated with one or more suitable adhesion promoters, depending on the type of materials used in the individual case. Next, a core 10 of a suitable hard hard wax or paraffin, the diameter of which corresponds to the internal diameter of the hollow space 5 and which is a little larger than the distance between the two cutting lines S, is pushed into the hollow space 5 of the profile 2 thread on both sides.

As shown in Figures 3 and 4, subsequently the transitional piece between the two ends of the profile strand is filled by injecting a suitable elastomer with the aid of an injection mold. The injection mold comprises a support plate 12, as a support and for placing the glass sheet 1, and the actual injection mold 13. The injection mold 13 has the cavity 14 calibrated open downwards, the cross section of which corresponds to the external cross section of the profile thread 2. The two sealing strips 16, which join the cavity 14 on the part of below the injection mold, they seal the hollow space to be closed against the glass surface and / or against the layer 6. The injection mold 13 is further provided with an injection opening 17 and also with holes 18 , in which, for example, electrical heating resistors are arranged. During the injection operation, the temperature of the injection mold 13 is actually regulated by the electrical heating elements at a certain level, which is a little above the melting temperature of the core 10. The heat radiation emitted by The surfaces of the mold is not sufficient, however, to melt the core material. Even during the same injection operation, the core 10 is not heated to its melting temperature, since the injected polymer has a relatively low temperature during injection and initially has an insulation layer corresponding to the mold surface of a temperature highest. Only after the end of the injection operation, when the mold 20 has been heated that it is molded again by direct contact with the mold surface of the cavity 14, is the heat transferred to the core 10. Before the core 10 is melted and distributed in the form of a more or less thin layer 22 on the bottom of the hollow space 5, however, the heating has resulted in the polymerization reaction of the mold 20, which at the beginning of the melting operation of the core 10 solidified at least to a certain degree retaining its desired shape. When the core 10 has melted and the polymerization reaction is over, the injection mold 13 is removed, and the glass sheet is taken from the support plate 12.

Claims (11)

1. A process for molding a hollow profile strand of an extrudable elastomer over the peripheral region of a sheet type article, characterized in that a locally limited portion of the cured profile strand is mechanically removed, at least partially, to a location of the hollow profile strand to be reformed, a core connecting the end portions therebetween, is pushed into the hollow space of the two mutually adjacent end portions of the hollow profile strand, the part of the article having the region that it is going to be reshaped surrounded by an injection mold and the hollow profile strand is completed at this location by injecting a healing elastomer into the injection mold, and subsequently the core is destroyed in such a way that the core material is distributed in the hollow space of the profile thread.

2. The process in accordance with the claim 1, characterized in that a core of brittle, brittle material is used, which is destroyed and reduced in size by the action of mechanical forces on the hollow profile portion that are re-molded.

3. The process according to claim 2, characterized in that a core comprising a small thin-walled tube is used.

4. The process in accordance with the claim 2, characterized in that a core of a foam-type material is used.

5. The process according to claim 1, characterized in that a core of a low melting material is used, which is melted by the subsequent heating of the recessed hollow profile portion.

6. The process in accordance with the claim 5, characterized in that a hard paraffin core having a melting temperature of between 50 and 130 ° C is used.

7. The process according to claim 5, characterized in that a core of a high melting wax having a melting temperature of between 50 and 200 ° C is used.

8. The process according to one of claims 1 to 7, characterized in that a single-component or multi-component reaction system is used as the curing elastomer for the termination of the hollow profile thread with the aid of the injection mold .

9. The process in accordance with the claim 8, characterized in that by using a reaction system, the curing reaction which is accelerated by exposure to heat.

10. The process according to one of claims 1 to 5, characterized in that the heating to melt the core takes place with the help of the hot injection mold.

11. The process according to one of claims 1 to 5, characterized in that the heating to melt the core is carried out after demolding the profile thread that was re-molded.