Monday, July 18, 2011

Liner Basics

For those who are inexperienced, picking a liner material can give you a headache, though this may be one of the more important packaging decisions you make.  A properly sealed liner can ensure freshness of the product and sustain it's shelf life.  Not any one liner can work for all products.  Because the liner comes in direct contact with the product, much attention should be paid to compatibility.  There are many liner types to choose from and from those types (especially induction liners) there can be many options among them.  Since we're starting with the basics, I will give you a rundown of the three most common liner types.  We'll save the specifics for another learning session.

Pressure Sensitive

Composed of polystyrene foam, this liner is pressure activated to seal to the container. Using an adhesive, the liner adheres to the container when the closure is screwed tight.  When the closure is removed, the liner remains sealed the the container.  Mainly used for dry products and can be used on Glass or plastic.



This is a three layer liner with HDPE outer surfaces and a foam inner cushion.  It is commonly used for liquids but can also be used for dry goods and semi-solids (creams).  This liner usually comes inside the closure from the manufacturer and remains in the top inside of the closure when removed from the container.  Because it has the inner foam cusion it presses into the top of the bottle when sealed and prevents leakage.

Heat Induction liners

Heat Induction liners leave a layer of aluminum foil on the container when the closure has been sealed to the container and heated.  It is important to pick an induction liner that is compatible with the material the container is made of.  There are options for how the liner will then be removed from the container such as clean peel, easy entry and tamper evident.  Heat Induction liners can also be used with additional liners such as PE foam or F-217. Since the induction liner is disposed of when the closure is removed, you may need an addition liner which will remain in the top of the closure to ensure a proper seal everytime the closure is removed and replaced.