Material Structure and Thickness of aluminum foil lid

What is aluminum foil lid?

An aluminum foil lid is a thin cover refers to pre-cut individual lids that are used to seal packaged goods in cups and other containers. It’s commonly found in food packaging, and industrial applications.

Main features of aluminum foil lid:

aluminum(often 30–50 micron thick) laminated and embossing with other materials for strength or barrier properties.

Can be a flat disc, a shaped pre-formed lid, or a peelable heat-sealed foil that adheres to a container rim.

Keeps food and beverages fresh by creating a barrier to air, moisture, and contaminants.

Blocks light, oxygen, and odors; provides a hygienic seal.

Some foil lids show visible damage if opened, improving product safety.

What does the material structure of aluminum foil lid refer to?

Aluminum foil lid is a type of flexible packaging product. Unlike other flexible packaging products, their material structure is relatively simple, consisting of a lamination of PET/aluminum and different types of plastic films. This is one of the factors determining the price of aluminum foil lid.

What are the commonly used material structure combinations for aluminum foil lid and what are their adaptability?

Simply put, the material structure of aluminum foil lid can be divided into three layers: the “printing layer,” the “barrier layer,” and the “sealant layer.” The “printing layer” is always made of PET, the “barrier layer” is always made of aluminum, and the “sealant layer” can be made of various plastic films, each of which must be compatible with the material of the container being sealed.

PET/AL/PP

aluminum foil lid with this material structure are suitable for containers made of PP. They are categorized into standard and pasteurized grades (indicating whether the PET/AL layers can withstand pasteurization at temperatures below 100°C).

PET/AL/CPS

aluminum foil lid with this material structure are suitable for containers made of PS.

PET/AL/CPE

aluminum foil lid with this material structure are suitable for containers made of PE.

PET/AL/PVC

aluminum foil lid with this material structure are suitable for containers made of PE.

What does the thickness of the material structure in aluminum foil lid refer to?

It refers to the total thickness of the “printing layer”, “barrier layer” and “sealant layer”. It can be obtained by measuring with a caliper at any position on aluminum foil lid. For example, if the measured data is 125 microns, then the net thickness should be 120 microns, because the remaining 5 microns is the thickness of the composite glue and solvent between the layers after drying, which does not need to be included.

How is the thickness of aluminum foil lid material structures determined?

Generally speaking, the thickness of aluminum foil lid before surface embossing is between 30-50 microns, and after embossing it becomes between 110-150 microns.

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