The encyclopedia · Product & Design · Product decision · 1946-1949
Earl Tupper's 'burping' lid made plastic airtight by flexing, not snapping
Tupper's oddly flexible lid sealed a bowl air- and water-tight when you pressed a corner and 'burped' the air out.
Tupperware · DuPont
the move
After the war Tupper Plastics made beads, cigarette cases and soap dishes. In 1946 Tupper got raw polyethylene from DuPont; the company believed the resin could not be moulded, but he worked out the formulation and made a container out of it.
The container's genius was the lid. Because it was flexible, pressing the centre forced the air out through a narrow gap, and the soft plastic resealed against the rim as it sprung back. The result was an airtight, watertight bowl that anyone could seal with one press.
He filed a patent on 2 June 1947 for an open-mouth container with that nonsnap closure, and the patent for the airtight container with its 'burping seal' was granted in 1949.
why it works
- The flexible lid vents the air on closing, then the returning shape creates the seal.
- Plastic is lighter and shatterproof compared with the glass and metal it replaced.
- The self-sealing design meant ordinary customers could make an airtight seal without instruction.
what transfers
Sometimes the winning move is a material the incumbent has rejected. A lid that seals by breathing out and then holding a gentle vacuum is simpler and more effective than a stiff, precise snap-fit.
what came after
Tupper's durable, lightweight containers found their real market not on store shelves but at the home parties that Brownie Wise built around them. The burping seal that made the product work became the backbone of the Tupperware party system and its worldwide direct-sales empire.
references
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