Capsule for closing a container

A closure capsule for closing a container, comprising:

• a cap (2) that can be associated with a container and comprising a frangible mouth (20);
• a cutter (3) comprising a cutting edge (30) designed to open said frangible mouth (20) which assumes a first configuration in which it is intact and a second configuration in which it is open;
• the cutter (3) also comprising a widening zone (31), wherein, as it moves away from the cutting edge (30), the transversal section of the cutter (3) increases;
• a covering (4) of the cap (2) and the cutter (3);
• in the first configuration at least the cap (2) and the cutter (3) define a tank (8) for containing a product destined to be dropped into the container in said second configuration;
• transmission means (5) for transmitting a rotary component from the covering (4) to the cutter (3);
• characterised in that it comprises moisture absorbing means (10) which overlap at least a portion of said cutter (3);
• said moisture absorbing means (10) comprising a tubular portion (101) which superposes internally of the cutter (3) and has a widening (102) of a section thereof which follows said widening zone (31) of the cutter (3);
• the tubular portion (101) has a thickness smaller than 3 millimetres.