Method and device for forming plastic cellular material in a mold from a foamable liquid reaction mixture
AssigneeIndustries et Techniques d'Ameublement
InventorAndre Contastin
Life of this patent
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Abstract
In the course of this method, an amount of expansible mixture is poured into a mould, after which the mould is obturated by means of a plug. A vacuum is created in the chamber of the mould by way of the plug so as to cause the foaming of the mixture. The vacuum is maintained for a period after the foamable mixture has filled the whole of the volume of the mould. At the end of the polymerization of the foamable mixture, the vacuum may be re-applied in the mould, preferably for several cycles, so as to cause the cells of the foam obtained to burst.
Claims15
Method for producing an object having a cellular structure in a mold, comprising two pivotally connected half-shells having a common joint plane and each having a shape corresponding to a part of the outer shape of the object to be produced, one of said half-shells having at least an aperture therein, said method comprising pivotally joining said half-shells together along said joint plane so as to form a closed mold cavity, pouring through said aperture a liquid mixture which is the precursor of a polymer material to be foamed to produce the finished object, said mixture being free from any blowing agent acting by evaporation, thereafter momentarily obturating said aperture, subsequently applying a vacuum through said aperture for establishing and maintaining a subatmospheric pressure in said mold cavity so as to allow the expansion of said mixture, said vacuum being maintained from the time of obturation until the foamed mixture is polymerized, releasing the vacuum from the mold and stripping the object from the mold.
Device for producing objects having a cellular structure comprising at least one mold having two flanged half-shells capable of being assembled on a joint plane, means defining in the mold an aperture by way of which aperture there is introduced in the mold a foamable liquid precursor of a polymer material for producing the finished object, a removable plug cooperative with the aperture, the plug comprising a tubular member defining an inner chamber and having an open end portion which is engagable in the aperture, the open end portion of the tubular member defining a valve seat, a valve closure member cooperative with the seat for closing said end portion, control means for directing movement of the closure member between a closed and an open position wherein said closure member respectively engages and disengages said seat, means located in the wall of one of said two half-shells and capable of detecting a level of the foam expanding in said mold and sending a signal to said control means for actuating said closure member when the foam reaches said level.
Dependencies are inferred from the claim text.