Screw cap

A method of manufacturing a screw cap,

• wherein the screw cap comprises:
• a top surface;
• and
• a side surface continuously extending downward from the top surface,
• wherein the side surface comprises a tapered surface tapered toward a bottom of the screw cap such that a width of the screw cap is tapered toward the bottom of the screw cap,
• wherein an upper edge of the tapered surface is located at an intermediate portion of the side surface in an up-and-down direction,
• the method comprising:
• preparing a mold frame comprising an upper mold frame and a lower mold frame;
• combining the upper mold frame and the lower mold frame together such that a bottom surface of the upper mold frame abuts against a top surface of the lower mold frame;
• forming the screw cap by introducing a plastic material into a space in the combined upper mold frame and lower mold frame,
• wherein the space has a shape conforming to the screw cap;
• and
• wherein a boundary between the abutting bottom surface of the upper mold frame and the top surface of the lower mold frame is aligned with the upper edge of the tapered surface of the screw cap in a side view of the screw cap;
• and
• opening the combined upper mold frame and lower mold frame.

A mold frame configured to manufacture a screw cap, comprising:

• an upper mold frame including an upper cavity inside thereof;
• and
• a lower mold frame including a lower cavity inside thereof,
• wherein the upper mold frame and the lower mold frame are configured to abut each other such that the upper cavity faces the lower cavity, and a bottom surface of the upper mold frame abuts against a top surface of the lower mold frame,
• wherein the lower cavity includes a side surface comprising a tapered surface tapered toward a bottom of the lower cavity such that a width of the lower cavity is tapered toward the bottom of the lower cavity, and
• wherein a boundary between the abutting bottom surface of the upper mold frame and the top surface of the lower mold frame is aligned with an upper edge of the tapered surface of the lower cavity in a side view of the mold frame.