What are bottle caps made of?

Bottle caps have been around since 1800. The first patent was created in 1892 by William Painter. The first caps required the use of a bottle opener. Lids are used to keep drinks from spoiling. They are used in various types of bottles and made of different materials.

Materials in bottle caps

The most common type of bottle cap is plastic. Plastic bottle caps are made from polyethylene terephthalate. This is a thermoplastic polymer resin that is part of the polyester family. This type of plastic is widely used in beverage and food containers. Depending on the processing method, this material can be transparent, opaque or white. This type of plastic is generally abbreviated as PET. It’s a different plastic from the one the bottle is made of. Metal caps are made of steel.

How caps are made

Plastic caps are created by injection molding. The plastic ingredients are put through a machine that heats and mixes them, and then injected into a mold cavity. In the mold cavity, the mixture cools and hardens into the shape of the mold. Metal caps are molded with a machine that creates the curves along the edges. Some metal caps have an additional plastic coating over them.

Features

Most bottle caps have company logos printed on them. Plastic caps are used on plastic bottles and metal caps on glass bottles. Slots are usually made on the inside of screw caps. Old metal caps require a bottle opener to remove. Some caps are hinged on the bottle. Often companies print code or game information inside the lids for contests. Some companies, print educational information inside their own.

Uses for bottle caps

Bottle caps are used to seal and keep drinks or liquids cool. They can also be recycled, which is beneficial for the environment. These caps are even considered currency in certain video games, such as Fallout. They can be used in craft projects. You can create different images by arranging colored metal lids on a cork board. Or you can glue several joints in a shape of your choice to make trivets. They can even be collectibles.

History

The first bottle caps were created in February 1892 by William Painter. They consisted of metal caps with 24 teeth and a cork with a paper backing separating the metal cap from the liquid contained in the bottle. They required the use of a bottle opener to pop them. Metal caps now only have 21 teeth, with no cork to separate them. Twist caps were introduced in the 1960s in Germany. They are sealed in bottles with grooves and no longer over a flange. These caps do not require the use of a bottle opener.