Synthetic resin cap, closing device, and container-packed beverage

A closing device comprising a container and a synthetic resin cap that is attached to an opening of the container,

• wherein the synthetic resin cap has a cap body having a top plate and a cylindrical section extending downward from the periphery of the top plate, a circular inner seal projection formed on an inner surface of the top plate and fits into a container opening, and a circular opening edge seal projection formed on the inner surface of the top plate and contacts an opening edge of the container opening,
• wherein the opening edge seal projection bends and deforms in an expanding radial direction until contacting the cap body at the time of attaching the synthetic resin cap to the container opening, and
• wherein a positioning protrusion is provided on the top plate and contacts the opening edge when the opening edge seal projection bend and deformed until contacting the cap body.

A container-filled beverage in which a beverage is filled in a closing device that comprising a container and a synthetic resin cap attached to an opening thereof,

• wherein the synthetic resin cap has a cap body having a top plate and a cylindrical section extending downward from the periphery of the top plate, and a circular inner seal projection formed on an inner surface of the top plate and fits into a container opening, and a circular opening edge seal projection formed on the inner surface of the top plate and contacts an opening edge of the container opening,
• wherein the opening edge seal projection bends and deforms in an expanding radial direction until contacting the cap body at the time of attaching the synthetic resin cap to the container opening, and
• wherein a positioning protrusion is provided on the top plate and contacts the opening edge when the opening edge seal projection bend and deformed until contacting the cap body.