Abstract: A synthetic resin cap mounted on a lip section of a container filled with a carbonated beverage includes a top plate section and a cylindrical section extending downward from a circumferential edge of the top plate section. An annular inner seal projection fitted into the lip section and an outer seal projection abutting an outer surface of the lip section are formed at an inner surface of the top plate section. An annular abutting convex section abutting the inner surface of the lip section is formed at an outer surface of the inner seal projection. The outer seal projection has an inner surface having an inner diameter reduced toward a distal end, and a minimum inner diameter section, which is a lower end of the inner surface, abuts the outer surface of the lip section at a position spaced apart from an opening end section toward a container main body.

Abstract: A synthetic resin cap comprises: a cap body having a top plate and a cylinder that is vertically lowered from the peripheral edge thereof; and a liner provided on a lower surface of the top plate. The liner has a flat plate; an inter-seal projection that contacts an inner-edge side of an opening end and has an outer-seal projection that contacts an outer-edge side of the opening end. An outer edge of the liner is spaced apart from the cylinder at an internal side and is formed to ensure a space between the outer edge and the cylinder. The outer diameter of the outer-seal projection is smaller than an outer diameter of the opening end.

Abstract: A synthetic resin cap comprises: a cap body having a top plate and a cylinder that is vertically lowered from the peripheral edge thereof; and a liner provided on a lower surface of the top plate. The liner has a flat plate; an inter-seal projection that contacts an inner-edge side of an opening end and has an outer-seal projection that contacts an outer-edge side of the opening end. An outer edge of the liner is spaced apart from the cylinder at an internal side and is formed to ensure a space between the outer edge and the cylinder. The outer diameter of the outer-seal projection is smaller than an outer diameter of the opening end.

Abstract: A synthetic resin cap mounted on a lip section of a container filled with a carbonated beverage includes a top plate section and a cylindrical section extending downward from a circumferential edge of the top plate section, wherein an annular inner seal projection fitted into the lip section and an outer seal projection abutting an outer surface of the lip section are formed at an inner surface of the top plate section. An annular abutting convex section abutting the inner surface of the lip section is formed at an outer surface of the inner seal projection. The outer seal projection has an inner surface having an inner diameter reduced toward a distal end, and a minimum inner diameter section, which is a lower end of the inner surface, abuts the outer surface of the lip section at a position spaced apart from an opening end section toward a container main body.

Abstract: The present invention provides a synthetic resin cap comprising: a cap body (4) having a top plate portion (2) and a cylinder portion (3) hanging from a circumferential edge portion (2b) thereof; an annular inside seal projection (12) to be fitted to a container mouth portion (21); a connector portion (15) formed between the top plate portion (2) and the inside seal projection (12); and an outside thin wall portion (16) formed on the top plate portion (2), and provides a closing device using thereof, and a container-packed beverage. When the internal pressure of the container has risen, the top plate portion (2) is deformably swelled upward, and an inward tensile force is applied to the inside seal projection (12) by the connector portion (15).