Patent ID: 7837927

Claim:
A method of producing an air inlet in a multi-walled container of the type consisting of an outer rigid casing inside which is placed a flexible pocket intended to contain a product and in association with a withdrawal member without air inlet, such a container being obtained in a mold by blow-molding coextrusion of a parison formed of a main outer layer made of relatively rigid plastic intended to form the outer rigid casing and a secondary inner layer made of relatively flexible plastic intended to form the flexible pocket, said layers having no adhesion between them so as to delaminate without difficulty, after the creation of a sprue in a portion of the parison during the blow-molding coextrusion operation, then removal of the sprue thus formed and finally the creation of an air inlet between the flexible layer and the rigid layer of the parison, the air inlet being obtained by making in the mold in at least one pinch zone of the parison a reservation intended to obtain a protrusion of said parison, the height of the protrusion being such as to allow at its end a first shearing operation at the sprue having the effect of fusing by crushing in this zone, two walls consisting of the outer layer with two walls consisting of the inner layer a second operation of cutting off the protrusion by means of a cutting tool, after opening of the mold and reworking of the container by rework templates, and a third operation, subsequent to or simultaneous with the second operation, consisting of initiating the delamination of the layers from one another by means of a mechanical means, wherein the initiation of the delamination is realized by exerting an axial force on the protrusion in a zone close to the latter.