Choosing the right base film directly determines packaging barrier performance, strength and suitability. Below is a concise breakdown of 7 core materials widely used in custom flexible packaging.

1. OPP / BOPP (Oriented / Biaxially Oriented Polypropylene) High transparency, good stiffness, excellent printability and moisture resistance, cost-efficient. Typical use: Surface printing layer for snacks, candies, biscuits and labels; usually laminated with CPP for heat sealability.

2. CPP (Cast Polypropylene) Superior heat sealability, good heat and oil resistance, high clarity. Typical use: Inner sealing layer for BOPP/CPP structures, standard for dry food, snacks and seasoning sachets.

3. PET (Polyethylene Terephthalate) High tensile strength, great dimensional stability, heat-resistant, precise print registration, good oxygen/moisture barrier. Typical use: Outer printing layer for retort pouches, coffee bags, pet food and cosmetic packaging; base film for metallized VMPET.

4. PE (Polyethylene) Excellent heat sealability, good flexibility and cold resistance, low cost, available in multiple densities. Typical use: The most widely used inner sealing layer for vacuum bags, frozen food and daily chemical packaging.

5. NY / PA (Nylon / Polyamide) Outstanding puncture and tear resistance, excellent low-temperature toughness and oil resistance. Typical use: Frozen meat, heavy-duty vacuum bags, retort pouches and oily food packaging, used as a middle functional layer.

6. AL (Pure Aluminum Foil) 100% barrier to light, oxygen, moisture and odor; excellent temperature resistance, premium metallic finish. Typical use: High-barrier core layer for pharmaceutical packaging, valved coffee bags and long-shelf-life food products.

Common Laminated Structures

· BOPP/CPP: For dry snacks, candies and general dry food

· PET/PE: For standard vacuum bags, frozen goods and daily chemicals

· PET/AL/PE: High-barrier solution for coffee, dried meat and condiments

· NY/PE: Puncture-resistant for frozen meat and heavy-duty packaging

· PET/NY/AL/PE: Maximum performance for retort pouches and pharmaceutical packaging

We customize material structures based on your product needs, shelf life and budget. Contact us for a professional recommendation and free quote.