| 摘要 |
A platen including an annular surface adapted to heat seal a piece of film to the lip of a cup, and a central projection which is hotter than the annular surface to cause greater shrinkage in a central portion than in the surrounding portion of the sealed piece of film. This shrinkage of the central portion and the resultant gathering of the surrounding portion results in a planar central portion of the sealed film with radially projecting ridges and grooves around its periphery. The ridges and grooves draw visual attention to the central portion and features, such as perforations for a straw-hole, located therein. |
