Flexible Packaging Materials Explained: PET, AL, NY, PE and More

Flexible packaging films are laminates — multiple layers, each with a specific job. Here is what each common layer does.

PET (Polyester)

The outer printable layer. PET is stiff, clear and heat-resistant, providing structure and a print surface. It makes pouches feel crisp and premium.

Aluminum Foil (AL)

The ultimate barrier. Foil blocks 100% of light, oxygen and moisture. It is the choice for coffee, tea, retort foods and anything needing 12-24 month shelf life. Foil also gives metallic printing effects.

NY (Nylon / PA)

Nylon adds puncture resistance and cold resistance, which is why it appears in frozen food and vacuum packaging. It also improves clarity and gloss.

PE / LLDPE / RCPP (Sealant Layers)

The food-contact inner layer that melts to form seals. LLDPE offers strong seals with low-cost processing; RCPP withstands 121°C retort. The sealant layer determines your sealing temperature window.

VMPET (Metallized PET)

A PET film with a thin metal coating — 90% of foil's barrier at lower cost and lighter weight. The standard choice for snacks and dried foods.

How to combine them

Typical structures: PET/AL/PE for maximum barrier, PET/VMPET/LLDPE for snacks, PA/PE for frozen, PET/AL/NY/RCPP for retort. Your product's moisture sensitivity, oil content and shelf life target determine the stack-up. We will recommend the optimal structure free of charge — ask us here.