Selecting the appropriate closure for your final package includes selecting the appropriate cap liner. Cap liners may be used to offer a tamper-evident seal, or as an additional oxygen barrier to extend the shelf life of your product. Because each liner is designed to serve a particular purpose, it is important to make sure the product you are packaging is compatible with the liner you select.
Pulp and Poly #
Pulp and Poly liners are made from 2 layers: pulp or paperboard, coated with a thin plastic film. The pulp layer lines the cap, while the plastic layer (usually PVC) faces the product and land of the bottle. This liner is good for liquids, oils or powders, including soaps or cosmetics.
PE Foam #
Polyethylene (PE) foam liners may be one layer or 3 layers (with a layer of PE foam between two layers of PE film). The PE foam allows for a compressible seal, although it is not airtight. Because there is no paperboard or pulp, the liners are dust free. PE foam liners are frequently used for personal care products, pharmaceutical, or some medical applications.
Induction liners have a foil laminate layer that seals with heat. Induction liners are sealed after the bottle is filled using a heat induction machine, creating a tamper evident seal. Induction liners are identified by the type of container they are compatible for sealing with, like a PE induction liner or a PET induction liner. For example, if a PET induction liner is paired with an HDPE bottle, the liner will not create an airtight seal.
Pulp and Foil #
Pulp and foil liners work well for foods, powders or essential oils. A layer of aluminum is sandwiched between a pulp layer and a plastic film layer. The film layer faces the product, while the pulp rests against the cap.
Pressure Sensitive #
Pressure sensitive liners have a layer of adhesive facing the bottle that activates with pressure. The adhesive sticks to the land of the bottle or jar when the cap is closed. Unlike induction lining, this does not create an airtight or tamper evident seal. However, pressure sensitive seals do help to prevent leaking, and are frequently used for powders or creams.
Liner Shapes #
The different liner shapes are normally used for heat induction liners. Tab liners have a tab for the user to peel the liner back; the tab can lay on the side of the bottle’s thread or be on top of the liner. Tri-tab liners have three tabs off the sides for the customer to peel the liner off the bottle. Lift ‘n Peel liners have a half circle on top to grip from.
Customizing your Liner #
Print customization is possible with the top layer of heat induction liner. Logos, a brand name, or simple messaging may be printed.