BRIEF DESCRIPTION OF THE FIGURES
Further features, details and advantages of the present disclosure will be explained with reference to an embodiment shown in the drawing. There are shown:
FIG. 1 is a schematic representation of a mold for the forming of a breast prosthesis with an inserted film pouch in which only the outer layer is filled with silicone in accordance with an intermediate step of the method in accordance with the present disclosure;
FIG. 2 is a representation in accordance with FIG. 1 in which the second chamber is also filled; and
FIG. 3 is a schematic representation of a mold for the forming of a breast prosthesis with an inserted film pouch in which only the outer layer is filled with silicone in accordance with an intermediate step with a cavity of the method in accordance with the present disclosure shaped similar to a membrane.
DETAILED DESCRIPTION
On the manufacture of the breast prosthesis in accordance with the present disclosure, a film pouch is welded first from at least three film layers. To the extent that three film layers are used, two chambers are formed. Alternatively, however, four film layers can also be welded together so that three chambers are created. The film used comprises polyurethane in a thickness of typically 40 μm to 100 μm. The welding of the film layers takes place by thermal welding, RF welding or laser welding. This film pouch is inserted into the prosthesis mold. In FIG. 1, the prosthesis mold is shown schematically. It comprises two mold halves 10 and 12. The precise design of the mold does not have to be explained here since it forms part of the prior art.
The films are initially not completely welded around the periphery so that there is still an inlet opening present here to fill in the silicone mixture. The first chamber, which is designated by 14 in FIG. 1, is filled first via the opening. A mold half 12 having a deep cavity is inserted into the mold to form the first chamber. The silicone layer contained in the first chamber is cross-linked either at room temperature or in a short furnace path, for example at 100° C., in a few minutes. The silicone used in the first chamber is formulated such that it cross-links at least so much at room temperature within a few minutes that the desired layer thickness and layer distribution is maintained in the further production steps. The cavity of the mold half 12 is configured such that only a hollow space remains free for the thin layer in this tool. The silicone in the first chamber is a silicone rubber which cross-links in an addition process without cleavage products. The softness is measured in penetration units and, in the normal case, lies between 170 and 230 units.
After forming an outer first silicone layer preferably having a thickness between 2 and 10 mm, the second chamber representing the main chamber is filled. Here, a light silicone, that is a mixture of silicone and hollow sphere material, is filled in. Subsequently, a new mold half, as shown in FIG. 2, namely a shallow form half 16 is placed on. This mold half is configured such that the second chamber is surrounded by the light silicone. This second chamber is designated by 18 in FIG. 2. The mold prepared in accordance with FIG. 2 subsequently runs through the main furnace process. The temperature in the furnace process is primarily based on the softening temperature and the softening times of the polyurethane film forming the pouch. The temperature is set such that a permanent plastic deformation is achieved in the polyurethane film; however, without the film being thermally damaged. Film temperatures of approx. 130° C. are usually set here.
After this production step, the prosthesis is taken out of the mold and the overhanging film is cut off, for example with a sharp knife, scissors or a stamping tool.
An alternative procedure is shown in FIG. 3. A membrane-like cavity 20 is present here whose shape is similar to a film layer which was deformed by vacuum or air pressure. The method used here substantially corresponds to the previously described method. It proves to be problematic in the previously described method to maintain the vacuum with high precision. This is made more difficult when the film layers become softer due to heating. The use of the membrane-like cavity makes it possible to maintain the contour in a defined state.
The present method has the advantage with respect to the manufacturing process using a deep cavity that the filling volume can be varied. The membrane-like cavity also does not have to be made so precisely as with a deep cavity. However, the mold must be positioned horizontally until the first layer has been sufficiently fully vulcanized.
It is also possible with the process to produce a third chamber on the side facing the body. The third chamber can be filled close in time to the first, outer chamber and can be fully vulcanized, at least in part, together or can be produced in two separate filling and vulcanization steps. Subsequently, the middle chamber is filled with light silicone and is fully vulcanized.
The third chamber can, however, also be configured as an extremely soft layer as described in EP 0 320 590 (Mulligan). Either the middle chamber is filled with light silicone and the rear chamber is filled close in time with extremely soft silicone and fully vulcanized together or they are filled and fully vulcanized in separate steps.
Patent Application
20070267131
