Container provided with an invertible diaphragm and a central portion of greater thickness

Container (1) made of a plastic material, provided with a base (7) including a standing ring (8) forming a support flange (9) and a diaphragm (11) extending from the standing ring (8) to a central portion (10), said diaphragm (11) being capable of standing in an outwardly-inclined position,

• wherein the diaphragm (11) connects to the standing ring (8) at an outer junction (12) forming an outer articulation of the diaphragm (11) with respect to the standing ring (8);
• wherein the diaphragm (11) connects to the central portion (10) at an inner junction (13) forming an inner articulation of the diaphragm (11) with respect to the central portion (10);
• whereby said diaphragm (11) is invertible with respect to the standing ring (8) to an inwardly-inclined position;
• whereby the central portion (10) has a thickness greater than the diaphragm (11), wherein the central portion (10) has an annular section (21) of greater thickness adjacent to the inner junction (13), the central portion (10) having a central recess (22) thinner than the annular section (21) and protruding upwardly from an inner edge of the annular section (21).