Abstract: Container closure, such as is suitable for being mounted in the exit aperture of the container and hermetically closing the exit aperture, and which comprises a first inflatable part (1) and a second part (3) suitable for being secured in the exit aperture, and means of separation (7) suitable for preventing a liquid held in said interior of said container from passing to said first inflatable part (1). The means of separation (7) can comprise a semi-permeable filter (8), suitable for allowing the passage of gases and for preventing the passage of liquids, or a hermetic division.