Plastisol is a common liner that is used for applications such as food canning and vacuum packing, because it provides a tamper evident and hermetic seal (or airtight seal.) When you open a metal closure and hear the “POP” noise, you know you have opened a plastisol lined closure.
How is a Plastisol Liner Made?
Plastisol liners begin as a liquid. After the metal closure is formed, the plastisol material is injected on the interior surface of the metal cap in a ring-like pattern. The metal caps then pass through an oven at specific time and temperature, causing the liquid to solidify and create an airtight seal. Through the process of filling, capping, and cooling, a vacuum can be drawn.
Things to be aware of.
Plastisol lined caps are paired with containers, such as hot fill food products, that can withstand high heat temperatures up to 212 degrees, or boiling. When pasteurizing products, plastisol liners can withstand 212 degrees for up to one hour. If you are looking to can your products, it is recommended to use retort plastisol liners because they can resist higher temperatures.
The table below is used as general guidelines for different types of plastisol liners and their associated properties / tolerances.