Production process of a seal

摘要

Process for the production by extrusion of a seal for jars of preserves and similar containers, especially made of glass, of the type consisting of a flexible rubber washer provided with an outer lateral gripping projection and with a line of least resistance formed on the seal between the junction of the projection with the washer and the inner periphery of the latter. The process according to the invention is characterised in that the seal is produced by the simultaneous extrusion of a main rubber mass and of a small quantity of crude rubber having a lower tearing strength than the main rubber mass, this small quantity of crude rubber being guided in the main rubber mass so as to be arranged between the junction (4, 11) of the projection (3, 10) with the washer (1, 9) and the inner periphery (6, 18) of the latter. The invention is used for the sealing of jars of preserves. IMAGE