Closure device for a container for liquids

Closure device for a container for drinking liquids, comprising:

• an elastically deformable membrane which has:
• a main body configured to be placed to close an opening of a container for liquids, delimited by an opening edge, the main body comprising a connection portion and an impervious main wall protruding from the connection portion, the main wall having a free edge opposite the connection portion,
• a lower body projecting from the connection portion of the main body and comprising a retaining flange adapted to engage with the edge of the container to constrain the membrane to the container, the lower body comprising a plurality of openings for the passage of liquids,
• wherein the free edge is configured to elastically deform when subjected to a suction action of a user, to put an environment inside the container in fluid communication with an environment outside it and allow liquids to exit from the openings,
• wherein the membrane is configured to elastically switch between a resting configuration, in which the free edge of the main body is spaced from the retaining flange of the lower body, and a working configuration, in which the free edge of the main body is close to the retaining flange of the lower body.