Invention and Engineering

Bottle cap

A bottle cap or bottle top is a common closure for the top opening of a bottle. A cap is sometimes colorfully decorated with the logo of the brand of contents. Metal caps with plastic backing are used for glass bottles, sometimes wrapped in decorative foil. Metal caps are usually either steel or aluminum, and of the crown cork type. Flip-top caps (like flapper closures) preceded such caps. Plastic caps are used for plastic bottles, functioning as screw caps, or plastic caps may have a pour spout rather than being detachable. Plastic caps are commonly made from polyethylene or polypropylene, and caps for plastic bottles are often made of a different type of plastic from the bottle. A cork stopper is another type of closure for the top of a bottle.

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See also

• ▸Buda Engine Co.
• ▸Geology of Arizona
• ▸Indian locomotive class WM

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