Sealing mechanism for a cylindrical container opening using a cap having a cap body and an upper lid

A sealing mechanism for a container opening comprising:

• a cylindrical opening disposed on a container body;
• and
• a cap for sealing the cylindrical opening, wherein the cap comprises:
• a cap body having a cylindrical shape with open ends and a sidewall for covering the outer surface of the cylindrical opening, and provided with a thread portion disposed on an inner surface of the cap body for engaging with a thread portion disposed on the outer surface of the cylindrical opening, and capable of moving up and down while rotating around the outer surface of the cylindrical opening;
• and
• an upper lid for closing one of the open ends of the cap body, and adhering to an open end surface of the cylindrical opening with an inner sealing element to seal the cylindrical opening,
• wherein the inner sealing element is a composite film provided with a plastic film layer for fusibly bonding to the upper lid, an intermediate layer, and a heat seal layer for fusibly bonding to the cylindrical opening,
• wherein the cap body and the upper lid are adjacent to each other and the cap body can be rotated without rotating the upper lid,
• wherein a recessed portion around an outer circumferential surface of the upper lid and a protruding portion extending radially inward from the sidewall of the cap body are engaged, and
• when the cap body rotates around the outer surface of the cylindrical opening to move the cap body away from the container body, a first abutting surface of the protruding portion and a first abutting surface of the recessed portion are abutted to each other with surface-to-surface contact, and when the cap body rotates around the outer surface of the cylindrical opening to move the cap body towards the container body, a second abutting surface of the protruding portion and a second abutting surface of the recessed portion are abutted each other with surface-to-surface contact,
• wherein a width (L1) of the first abutting surface of the recessed portion in the radial direction is larger than a width (L2) of the second abutting surface of the recessed portion in the radial direction, and
• when the cap body is moved away from the container body, the cap body slidably abuts on the upper lid, and pushes up the upper lid to open the cylindrical opening, and when the cap body is moved towards the container body, the cap body abuts on the upper lid and pulls down the upper lid to re-seal the cylindrical opening.