| 摘要 |
A thermoplastic heat seal is created between a polymeric shrink film and a polymeric surface of an open top container. Radiant energy is uniquely focused on the periphery of the film that has been at least partially modified to absorb it. Sufficient heat is generated to not only soften the film needed to effect a thermoplastic heat seal but also to simultaneously shrink the film, urging it towards the rim of the container. The shrinking force of the film provides the required pressure needed to complete the thermoplastic bond. An effective spill resistant lid that can withstand the heat and steam of hot beverages is now possible. Also disclosed is a polymeric lid adapted to provide access means to a hot beverage. This includes a pull tab created by at least partially eliminating radiant energy absorbing material in an extremity of the polymeric film. Also disclosed are novel means to efficiently transport and position a thin, pliable and limp material. |
