Pre-slit donut break seal

A method of making a seal, the method comprising:

• dispensing in horizontal alignment a foam sheet comprising a thermoplastic polymer, the foam sheet having preformed openings;
• dispensing in horizontal alignment a fluoropolymer film adjacent the foam sheet;
• heating the foam sheet and the fluoropolymer film with an open flame, positioned between the foam sheet and the fluoropolymer film;
• pressing the foam sheet to the fluoropolymer film to form a construct without intervening layers between the foam sheet and the fluoropolymer film;
• cooling the construct;
• and
• cutting a seal body from the construct, the seal body comprising a foam layer and a fluoropolymer film layer, a preformed opening defining an inner contour of the foam layer, the seal body having an outer contour, the fluoropolymer film layer extending inwardly from the outer contour beyond the inner contour.

A container comprising:

• a vessel having an opening;
• and
• a seal covering the opening in the vessel, the seal comprising a foam sheet having first and second major surfaces and having an outer contour and an inner contour, the inner contour defining an opening, the foam sheet comprising a thermoplastic polymer;
• and
• a film directly contacting the first major surface of the foam sheet without intervening layers, the film extending inwardly beyond the inner contour and the film comprising a fluoropolymer.